session viii concepts and principles of the …session viii concepts and principles of the...

HS 178 R1/02

Three Hours and Twenty Minutes

SESSION VIII

CONCEPTS AND PRINCIPLES OF THE STANDARDIZED FIELD SOBRIETY TESTS (SFST)

HS 178 R1/02

SESSION VIII CONCEPTS AND PRINCIPLES OF THE STANDARDIZED FIELD SOBRIETY TESTS(SFST) Upon successfully completing this session, the student will be able to: o Discuss the development and validity of the research and the standardized elements,

clues and interpretation of the three standardized field sobriety tests. o Discuss the different types of nystagmus and their effects on the Horizontal Gaze

Nystagmus test. o Discuss and properly administer the three standardized field sobriety tests. o Discuss and recognize the clues of the three standardized field sobriety tests. o Describe in a clear and convincing manner and properly record the results of the

three standardized field sobriety tests on a standard note taking guide. o Discuss the limiting factors of the three standardized field sobriety tests. CONTENTS SEGMENTS LEARNING ACTIVITIES A. Overview: Development and Validation o Instructor-Led Presentation

B. SFST Field Validation Studies o Instructor-Led Demonstration C. Horizontal Gaze Nystagmus o Student Practice Session and

DemonstrationD. Vertical Gaze Nystagmus E. Walk-and-Turn

F. Combining the Clues of the Horizontal Gaze Nystagmus and Walk-and-Turn G. One-Leg Stand H. Limitations of the Three Tests I. Taking Field Notes on the Standardized Field Sobriety Tests

Display Slide VIII-O (Session Objectives)

Aides Lesson Plan Instructor Notes

HS 178 R1/02 VIII-1

3 Hours 20 Minutes

VIII CONCEPTS ANDPRINCIPLES OF THESTANDARDIZED FIELDSOBRIETY TESTS (SFST)

15 Minutes

A. Overview: Developmentand Validation

DisplayOverheadVIII-1

1. For many years law enforce-ment officers have utilizedfield sobriety tests todetermine the impairment of aperson's driving due to alcoholinfluence. The performance ofthe person on those fieldsobriety tests was used by theofficer to develop probablecause for arrest and as evi-dence in court. A wide varietyof field sobriety tests existedand there was a need todevelop a battery ofstandardized valid tests.

Point out to students thatNHTSA contracted with theSouthern California ResearchInstitute (SCRI) in 1975 todevelop these field tests. SCRI published the followingthree reports:

California: 1977 (Lab)California: 1981 (Lab andField)Maryland, D.C., V.A., N.C.,1983 (Field)

DisplayOverheadVIII-1A

2. Beginning in late 1975, exten-sive scientific research studieswere sponsored by NHTSAthrough a contract with theSouthern California ResearchInstitute (SCRI) to determine -which roadside field sobrietytests were the most accurate.


HS 178 R1/02 VIII-2


3. SCRI traveled to law enforce-ment agencies through theUnited States to select themost commonly used fieldsobriety tests. Six tests wereused in the initial stages ofthis study.

4. Laboratory research indicatedthat three of these tests, whenadministered in a standardizedmanner, were a highly reliablebattery of tests for distin-guishing BACs above 0.10:

o Horizontal Gaze

Nystagmus (HGN)o Walk-and-Turn (WAT)o One-Leg Stand (OLS)


5. NHTSA analyzed thelaboratory test data and found:

o HGN, by itself, was 77%accurate.

o WAT, by itself, was 68%accurate.

o OLS, by itself, was 65%accurate.

o By combining the results ofHGN and WAT, an 80% ac-curacy rate can beachieved.


6. The final phase of this studywas conducted as a fieldvalidation.


HS 178 R1/02 VIII-3


o Standardized, practical andeffective procedures weredeveloped.

DisplayOverheadVIII-4B

o The tests were determinedto discriminate in the field,as well as in the laboratory.

7. The three standardized testswere found to be highlyreliable in identifying subjectswhose BACs were above 0.10. The results of the studyvalidated the SFSTs.

15 Minutes

B. SFST Field ValidationStudies


1. Three SFST validation studieswere undertaken between 1995and 1998:

o Colorado - 1995o Florida - 1997o San Diego - 1998

See Attachments D, E, and F.


2. The Colorado SFST validationstudy was the first full fieldstudy that utilized law enforce-ment personnel experienced inthe use of SFSTs.

o The original SCRI studyutilized only a fewexperienced officers inDWI enforcement in both alaboratory setting and fieldsetting.


HS 178 R1/02 VIII-4

o Based on the 3-test battery (HGN, WAT, OLS),correct arrest decisionswere made 93% of the time.Substantially higher thanthe initial study results.

3. The Florida SFST field valida-tion study was undertaken inorder to answer the question ofwhether SFSTs are valid andreliable indices of the presenceof alcohol at 0.08 levels andabove when used underpresent day traffic and lawenforcement conditions.


o Based on the 3-test battery(HGN, WAT, OLS), correctdecisions to arrest weremade 95% of the time.

o This study has shown thatthe SFST 3-test battery isthe only scientificallyvalidated and reliable method for discriminatingbetween impaired andunimpaired drivers.

4. The San Diego SFST field vali-dation study was undertakenbecause of the nationwidetrend towards lowering theBAC limits to 0.08. Thequestion to be answered was“does SFST discriminate atBAC’s below 0.10".


HS 178 R1/02 VIII-5


o Based on the 3-test battery(HGN, WAT, OLS), arrestdecisions were supported91% of the time at the 0.08BAC level and above.

o HGN is still the most reli-able of the 3-test battery.

This study provided thefirst indications supportingarrest decisions at 0.08BAC. The study alsosuggests that HGN canprovide valid indications of0.04 BAC and above.

Note: Refer to Session VIII,Attachment B for informationregarding all SFST researchstudies.

1 Hour 15Minutes

C. Horizontal GazeNystagmus

1. Review of definition.

a. Involuntary jerking of theeyes, occurring as the eyesmove toward the side.


b. In addition to beinginvoluntary:

o person is usuallyunaware that it ishappening.

o person is powerless to

stop it or control it.

2. Key Summary Point.

a. Alcohol and certain otherdrugs cause HorizontalGaze Nystagmus.


HS 178 R1/02 VIII-6


3. Categories of Nystagmus.

a. Horizontal GazeNystagmus is not the onlykind of nystagmus.

b. There are other circum-

stances under which theeyes will jerk involuntary.

c. It is important to knowsome of the other commontypes of nystagmus, to beaware of their potentialimpact on our field sobrietytests.

d. Nystagmus of several dif-ferent origins may be seen. There are three generalcategories of nystagmus:

(1) Vestibular Nystagmusis caused by movementor action to thevestibular system.

Reveal the first category onSlide VIII-10.

(a) Types of vestibularnystagmus:

Rotational Nystag-mus occurs whenthe person is spunaround or rotatedrapidly, causing thefluid in the innerear to be disturbed.

Point out that the vestibularsystem is a sense organlocated in the inner ear. Itprovides information to thebrain, and consequently to theeyes about position andmovement of the head tomaintain orientation andbalance of the body.

If you were able to observe theeyes of a rotating person, theywould be seen to jerknoticeably.


HS 178 R1/02 VIII-7

Post RotationalWhen the personstops spinning, thefluid in the innerear remains dis-turbed for a shortperiod of time, andthe eyes continue tojerk.

Also indicate that these typesof nystagmus will notinterfere with the horizontalgaze nystagmus test due tothe conditions under whichthey occur.

To illustrate rotational andpost rotational, swirl a halfglass of water several times. Stop swirling glass, water willcontinue to spin for a shortperiod of time.

Caloric Nystagmusoccurs when fluidmotion in the canalsof the vestibularsystem is stimula-ted by temperatureas by putting warmwater in one earand cold in theother.

Positional AlcoholNystagmus (PAN)occurs when a for-eign fluid, such asalcohol, that altersthe specific gravityof the blood is inunequal concentra-tions in the bloodand the vestibularsystem.

NOTE: The originalresearch does notsupport the administra-tion of HGN to someonewho is lying down.

This causes the vestibularsystem to respond to gravityin certain positions, resultingin nystagmus.

There are two types of PAN:

PAN I-occurs when thealcohol concentration in theblood is greater than the innerear fluid. PAN I occurs whileBAC is increasing.


HS 178 R1/02 VIII-8

PAN II - occurs when thealcohol concentration in theinner ear fluid is greater thanin the blood. An example ofPAN is the spinning of a roomwhen a person lies down afterconsuming alcohol. This oc-curs while BAC is decreasing.

(2) Nystagmus can alsoresult directly fromneural activity:

Reveal the next category onSlide VIII-10.

Optokinetic Nystagmusoccurs when the eyesfixate on an object thatsuddenly moves out ofsight, or when the eyeswatch sharply contrast-ing moving images.

Examples ofoptokinetic nystagmusinclude watching strobelights, rotating lights,or rapidly movingtraffic in closeproximity.

The Horizontal GazeNystagmus test will notbe influenced by optoki-netic nystagmus ifadministered properly.

Point out that during theHorizontal Gaze Nystagmustest, the suspect is required tofocus the eyes on a penlight,pencil or similar object thatmoves smoothly and relativelyslowly across the field of view,thus optokinetic nystagmuswill not occur.

PhysiologicalNystagmus is a naturalnystagmus that keepsthe sensory cells of theeye from tiring. It is themost common type ofnystagmus.

Emphasize that physiologicalnystagmus will have noimpact on our standardizedfield sobriety tests, becauseits tremors are generallyinvisible.


HS 178 R1/02 VIII-9

It happens to all of us,all the time. This typeof nystagmus producesextremely minortremors or jerks of theeyes.

These tremors aregenerally too small tobe seen with the nakedeye.

Gaze Nystagmus occursas the eyes move fromthe center position. Gaze nystagmus is sep-arated into three types:

Horizontal GazeNystagmus occurs asthe eyes move to theside. It is the observa-tion of the eyes forHorizontal GazeNystagmus that pro-vides the first and mostvalid test in the stand-ardized field sobrietytesting battery.Although this type ofnystagmus is mostaccurate fordetermining alcoholinfluence, its presencemay also indicate use ofcertain other drugs.

Emphasize to students thatthis training course isconcerned with HorizontalGaze Nystagmus and that thisprocedure has been validatedas an accurate indicator foralcohol influence by extensivescientific research.

Alcohol is a central nervoussystem depressant.

Examples of other drugs are: Depressants, Inhalants, PCPand its analogs.


HS 178 R1/02 VIII-10

Vertical Gaze Nystag-mus occurs as the eyesgaze upward. Thepresence of this type ofnystagmus is associatedwith high doses of alco-hol for that individualand certain otherdrugs.

NOTE: All drugs that induceHGN may also induce VGN, ifenough of the drug is taken.

The drugs that produceVertical Nystagmus arethe same ones thatproduce HorizontalGaze Nystagmus.

There is no drug thatwill cause VGN thatdoes not cause HGN. IfVGN is present andHGN is not, it could bea medical condition.

(3) Nystagmus may also becaused by certainpathological disorders. They include braintumors and other braindamage or some dis-eases of the inner ear. These pathologicaldisorders occur in veryfew people and in evenfewer drivers.

Reveal the next category onSlide VIII-10.

Point out that nystagmuscaused by pathologicaldisorders is extremely rare inthe driving population. Persons suffering from thesedisorders are rarely able todrive.

4. Medical Impairment.

a. The observations that youcan make to assess possiblemedical impairmentinclude:


HS 178 R1/02 VIII-11

o Resting Nystagmuso Tracking ability o Pupil size

b. Resting Nystagmus isreferred to as jerkingas the eyes lookstraight ahead. Thiscondition is notfrequently seen. Itspresence usually indi-cates a pathology orhigh doses of a drugsuch as PCP.

NOTE: Resting Nystagmusmay also be a medicalproblem.

Although this observation isan important medicalassessment, it is NOT an HGNadministrative procedurestep.

c. Tracking Ability will beaffected by certain medicalconditions or injuriesinvolving the brain:

Demonstrate how to check fortracking ability.

o If the two eyes do nottrack together, thepossibility of a seriousmedical condition orinjury is present.

Point out: Even though thepossibility of alcohol and/ordrug impairment exists,officers should be aware ofmedical conditions havingsymptoms in common withalcohol influence.

o By passing a stimulusacross both eyes, youcan check to see if botheyes are trackingequally.

o If they don't (i.e., if oneeye tracks the stimulus,but the other fails tomove, or lags behindthe stimulus) there isthe possibility of aneurological disorder.

Note: Testing for HGN in asubject with an eye disorderor an artificial eye has notbeen validated by research.


HS 178 R1/02 VIII-12

o If a person has sight inboth eyes, but the eyesfail to track together,there is a possibilitythat the person is suf-fering from an injury orillness affecting thebrain.

d. Pupil Size will be affectedby some medical conditionsor injuries:

Note: For further informationon drugs other than alcoholand procedures for conductinga preliminary examination tocheck for medical impairment,injury or drug impairment,see the curriculum packageentitled "Drugs That ImpairDriving", or “Introduction toDrugged Driving” availablefrom the NHTSA.

o If the two pupils aredistinctly different insize, it is possible thatthe subject has a glasseye, or is suffering froma head injury or aneurological disorder.


5. Administrative Procedures forHorizontal Gaze Nystagmus.

It is important to administerthe Horizontal GazeNystagmus test systematically,to ensure that nothing isoverlooked.

Prior to administering HGN,check to see if the subject hasany eye problems or eyeabnormalities.

a. Begin by instructing thesuspect to removeeyeglasses, if worn.

Point out that eyeglasses mayimpede the suspect's peri-pheral vision, and may alsoimpede the officer's ability toobserve the eye carefully.

o It does not matterwhether the suspectcan see the stimuluswith perfect clarity, aslong as suspect can seeit at all.

Remind students thatnystagmus is not a vision test.


HS 178 R1/02 VIII-13

b. Give the suspect the appro-priate verbal instructions:

o Put feet together,hands at the side.

o Keep head still

Point out that officers shouldnote whether suspect sways,wobbles, etc. while trying tobalance.

o Look at the stimulus

o Follow movement ofthe stimulus with theeyes only

Emphasize that these are themajor points that must beconveyed during the verbalinstructions.

o Keep looking at thestimulus until told thetest is over

c. Position the stimulus ap-proximately 12-15 inches(30-38 cm) in front ofsuspect's nose, and slightlyabove eye level tocommence the test.

Resting Nystagmus may beobserved at this time. Officers should note whetherthe suspect displays RestingNystagmus.

d. Check for equal tracking. Move the stimulus rapidlyfrom center to far right, to farleft and back to center(approximately 2 seconds).

e. Check for equal pupil size. Demonstrate by placing coins(penny and dime) next to eachother on an overheadprojector.

f. Check the left eye for lackof the "Smooth Pursuit"clue. If the eye is observedto jerk while moving, thatis one clue.

Remind students to also checkfor resting nystagmus whenchecking for equal pupil size.


HS 178 R1/02 VIII-14

o Check the right eye forlack of the "SmoothPursuit" clue andcompare.

Remind students to make atleast two complete passes infront of the eyes to check thisclue.

g. Check the left eye for the"distinct nystagmus atmaximum deviation" clue. If the jerkiness is distinct,that is one clue.

Emphasize that the jerkingmust be definite and distinctin order to score this clue.

NOTE: For questionsregarding Fatigue Nystagmussee page VIII-22.

o Check the right eye forthe "distinct nystagmusat maximum deviation"clue and compare.

Point out that in most casesno white should be showing inthe corner of the eye whenobserving this clue.

h. Check the left eye for the"onset of nystagmus priorto 45 degrees" clue. If thejerking begins prior to 45degrees, that is one clue.

Remind students to checkeach eye at least twice for thisclue.

o Check the right eye for"onset of nystagmusprior to 45 degrees"clue, and compare.

i. Total the clues

o Maximum number ofclues possible for eacheye: 3

o Total maximum number

of clues possible forboth eyes: 6

Point out that, for manysuspects, nystagmus clues willappear in the sequence listed. That is, as BAC increases,many people first showinability of smooth pursuit,then show distinct jerkinessat maximum deviation, andfinally show an onset within45 degrees. However, thatmay not be true in all cases: the clues may develop invirtually any sequence, in anyparticular suspect.


HS 178 R1/02 VIII-15

Also, point out that the sus-pect's performance many notbe exactly identical in botheyes. It is possible that allthree clues definitely will befound in one eye, while onlytwo (or sometimes only one)will show up in the other eye. It is always necessary to testboth eyes, and to test themindependently.

Notwithstanding, it isunlikely that the eyes ofsomeone under the influenceof alcohol will behave totallydifferent.

Thus, if one eye shows allthree clues distinctly whilethe other eye gives noevidence of nystagmus, theperson may be suffering fromone of the pathologicaldisorders covered previously.


6. Clues for Horizontal GazeNystagmus.

a. When we administer theHorizontal Gaze Nystag-mus test, we look for threespecific clues as evidenceof alcohol influence.

b. We check each eye

independently for eachclue.

It is important that studentalways start with left eyefirst. Then check right eye forsame clue. This proceduremust be used for all threeclues.

Always start with subject'sleft eye.


HS 178 R1/02 VIII-16

c. For standardization, beginwith the subject's left eye. Check for the first clue.Next, check right eye forsame clue. Repeat thisprocedure for each cluestarting with left eye, thenright eye. Compare anddocument the results.

d. When we are testing aneye, it is good practice toadminister the test by-the-numbers each time, tomake sure that no step isoverlooked.

EMPHASIZE THAT:OFFICER SAFETY IS OFKEY IMPORTANCEWHEN ADMINISTERINGTHESE TESTS.


e. Clue No. 1: Lack of SmoothPursuit.

o The first clue requiresthat the suspect movethe eye to follow themotion of a smoothlymoving stimulus.

Emphasize that suspect mustkeep the head still and followthe stimulus with the eyesonly.

o The stimulus may bethe eraser on a pencil,the tip of a penlight,the tip of your finger,or any similar smallobject.

Emphasize here that it is bestto use a stimulus which has acontrasting tip or focal point.

o Begin by holding thestimulus approximately12-15 inches (30-38 cm)in front of the suspect'snose, and slightlyhigher than the level ofthe suspect's eye.

Point out that when stimulusslightly higher than eye level,suspect will have to open eyeswide to focus on it. Wide-open eyes make it easier tosee the nystagmus.


HS 178 R1/02 VIII-17

o Move the stimulussmoothly all the wayout to the right (check-ing suspect's left eyefirst) then move thestimulus smoothly allthe way across the sus-pect's face to the leftside (checking the sus-pect's right eye), thenback to center.

o Make at least twocomplete passes withthe stimulus.

Analogy: movement of a non-impaired person's eye will besimilar to the movement of amarble rolling across apolished pane of glass (i.e.,frictionless).

o If a person is notimpaired, the eyesshould move smoothlyas the object is movedback and forth.

o If the person isimpaired by alcoholand/or some otherdrugs, the eye shouldjerk noticeably as itmoves back and forth.

Analogy: movement of animpaired person's eyes will besimilar to a marble rollingacross a sheet of sandpaper(encountering resistance,friction).

Note: This will also be seenwith certain categories ofdrugs.

(1) The Mechanics of ClueNumber 1.

o It is necessary to

move the objectsmoothly to obtain atrue test of theeye's ability topursue smoothly.


HS 178 R1/02 VIII-18

o The stimulusshould be movedfrom center posi-tion, all the way outto the right side(checking subject'sleft eye) where theeye can go nofurther, and thenall the way backacross subject's faceall the way out tothe left side wherethe eye can go nofurther (checkingsubject's right eye)and then back tothe center.

Demonstrate.

o The object must bemoved steadily, at aspeed that takesapproximately 2seconds to bring theeye from center toside.

Point out that the stimulusshould be moved at a speedthat requires approximatelytwo seconds to bring it fromthe center out all the way tothe right side. It should bereturned toward the subject'snose at the same speed.

o A good practice isto hold the elbowstiff, but slightlybent, and to pivotthe entire arm fromthe shoulder.

Demonstrate.

o In testing for thisclue, make at leasttwo completepasses in front ofthe eyes.

Demonstrate.


HS 178 R1/02 VIII-19

o If you are still notable to determinewhether or not theeye is jerking as itmoves, additionalpasses may be madein front of the eyes.

(2) Live Demonstration ofthe Mechanics of ClueNo. 1.

Solicit a student to participatein the live demonstration.

Station the student-subject ina position where the eyes caneasily be seen by the class. (Itmay be necessary to conductthe demonstration at two ormore locations in the class topermit all to see.)

o Position stimulusapproximately12-15 inches (30-38cm) in front of nose,slightly higher thaneye level.

Articulate each step in theprocedural mechanics aloud.

o Stimulus is movedsmoothly from cen-ter all the way outto the right(checking subject'sleft eye), backacross subject's faceall the way to theleft side (checkingsubject right eye)then back to center.

Point out how the arm is heldto ensure smooth movement.

o A second pass isconducted the sameas the first.

Point out that each pass takesthe eye as far to the side as itcan go.


HS 178 R1/02 VIII-20

o On each pass, thearm is movedsmoothly, and theeye is taken as farto the side aspossible.

Point out that it takes appro-ximately 2 seconds to movethe object from center to theside as far as the eye can go. Solicit students' questionsconcerning the proceduralmechanics for Clue No. 1.

(3) Student practice of themechanics of Clue No.1.

o Practice in groupsof two or three,taking turns.

Instruct each student topractice conducting the test ofsmooth pursuit, using anotherstudent as a subject.

Remind students that they areto make at least two completepasses in front of the eyes.

o Coaching andcritiquing students'practice.

Common initial mistakes tonote and correct: o Holding object too close to

(or too far from) subject'seyes;

o Moving object too slowly (ortoo quickly) toward the side;

o Failing to move object farenough to the side to bringeye to maximum deviation.

o Curving downward andcurving around. Note: Encourage students topractice this procedureusing a flat surface such as awall for a guide.


HS 178 R1/02 VIII-21

o Student-leddemonstration.

Choose a student who appearsto be doing a good job incarrying out the proceduralmechanics of Clue No. 1, andhave that student comeforward with a subject todemonstrate the mechanics tothe class.

Resume student practice andallow it to continue until allstudents appear reasonablyproficient in carrying out themechanics of Clue No. 1.


f. Clue No. 2: DistinctNystagmus at MaximumDeviation.

o Once you have com-pleted the test ofsmooth pursuit, youwill test the eyes fordistinct nystagmuswhen the eye is held atmaximum deviation,beginning with thesubject's left eye.

(1) The Mechanics of ClueNumber 2.

o Once again, positionthe stimulusapproximately 12-15inches (30-38 cm) infront of subject'snose.

Demonstrate


HS 178 R1/02 VIII-22

o Move the stimulusoff to the right side(checking suspect'sleft eye) until theeye has gone as faras possible.

Demonstrate holding thestimulus steadily off to theside.

o Hold the stimulussteady at that posi-tion for a minimumof four (4) seconds,and carefully watchthe eye.

o Then, move thestimulus back acrossthe subject's face allthe way out to theleft side (subject'sright eye).

Point out that four (4) secondsis a relatively long period oftime. You cannot simply holdthe eye to the side for aninstant, and expect to observedistinct jerking.

Note: Fatigue Nystagmus. This type of nystagmus maybegin if a subject’s eye is heldat maximum deviation formore than 30 seconds.

o Hold the stimulussteady and carefullywatch the eye.

o If the person isimpaired, the eye islikely to exhibit defi-nite, distinct andsustained jerkingwhen held at maxi-mum deviation for aminimum of 4seconds.

Emphasize this point.

o In order to "count"this clue asevidence ofimpairment, thenystagmus must bedistinct and sus-tained for a mini-mum of 4 seconds.

ONCE AGAIN, EMPHASIZEOFFICER SAFETY.


HS 178 R1/02 VIII-23

o If you think you seeonly slight nystag-mus at this stage ofthe test, or if youhave to convinceyourself thatnystagmus ispresent, then itisn't really there.


o Stimulus initiallypositioned approxi-mately 12-15 inches(30-38 cm) in front ofthe student-subject'snose, slightly higherthan eye level.

o Stimulus moved tothe side, drawingthe eye to its maxi-mum deviation.

o Hold the stimulussteady at that pointfor a minimum of 4seconds, to deter-mine whether ornot there is distinctand sustainednystagmus.


o Then, move thestimulus backacross the subject'sface all the way outto the left side(subject's right eye).

Station the student-subject ina position where eyes canreadily be seen by the class. (It may be necessary toconduct the demonstration attwo or more locations in theclass.)


HS 178 R1/02 VIII-24

o Hold the stimulussteady and carefullywatch the eye.


o Hold the stimulussteady at that pointfor a minimum of 4seconds to deter-mine whether ornot there is distinctand sustainednystagmus.



Instruct each student topractice conducting the test ofmaximum deviation, usinganother student as a subject.

o Coaching andcritiquing students'practice.

Common initial mistakes tonote and correct: o not bringing the eye

sufficiently far to the side(some white still showing).

o not holding the objectsteadily for at least fourseconds, at maximumdeviation.

o Student-ledDemonstrations

Allow student practice tocontinue until all studentsappear reasonably proficientin carrying out the mechanicsof Clue No. 2.

Solicit students' questionsconcerning the proceduralmechanics for Clue No. 2.


HS 178 R1/02 VIII-25


g. Clue No. 3: Onset ofNystagmus Prior to 45Degrees.

o Once again, positionthe stimulusapproximately 12-15inches (30-38 cm) infront of subject's nose.

EMPHASIZE OFFICERSAFETY.

o The angle of onset ofnystagmus is simplythe point at which theeye is first seen jerking.

o Generally speaking, thehigher the BAC, thesooner the jerking willstart as the eye movestoward the side.

Examples: With someone at avery high BAC (0.20+), thejerking might begin almostimmediately after the eyestarts to move toward theside. For someone at 0.08BAC, the jerking might notstart until the eye has movednearly to the 45 degree angle.

o If the jerking beginsprior to 45-degrees,that person’s BACcould be 0.08 or above.

REMIND STUDENTSTHAT THE ADMINI-STRATION OF HGN ISNOT TO BE USED TOESTIMATE SPECIFICBAC LEVEL.

o It is not difficult to de-termine when the eyehas reached the 45-de-gree point, but it doesrequire some practice.

o If you start with thestimulus approximately12-15 inches (30-38 cm)directly in front of thenose, you will reach45-degrees when youhave moved thestimulus an equaldistance to the side.

Instruct students thatwhatever distance youposition the stimulus from thenose, you will reach 45degrees when you have movedthe stimulus an equal distanceto the side. (i.e., If you startwith the stimulus 12 inchesfrom the nose, move it 12inches to the side.)


HS 178 R1/02 VIII-26

o Two other importantindicators can be usedto determine if the eyeis within 45 degrees:

- at 45 degrees, somewhite usually willstill be visible inthe corner of theeye (for mostpeople).

Point out the white showingin the eye portrayed in SlideVIII-19. Note that somepeople's eyes may exhibit nowhite in the corner prior to45-degrees.

Point out alignment ofstimulus and shoulder in SlideVIII-19.

- If you started withthe stimulus appro-ximately 12-15inches (30-38 cm) infront of the suspect,when you reach 45degrees the stimu-lus will usually belined up with, orslightly beyond, theedge of the subject'sshoulder.

Point out that this latterindicator may not be valid ifthe suspect is either a verylarge or a very small person.

(1) The Mechanics of ClueNo. 3.

o The stimulus ispositioned approxi-mately 12-15 inchesfrom (30-38 cm)subject's nose.

o It is necessary tomove the stimulusslowly to identifythe point at whichthe eye begins tojerk.


HS 178 R1/02 VIII-27

o Start moving thestimulus towardsthe right side (lefteye) at the speedthat would takeapproximately 4seconds for thestimulus to reachthe edge of thesuspect's shoulder.

Demonstrate stopping thestimulus, and holding itsteady.

o As you are slowlymoving the stimu-lus, watch the eyecarefully for anysign of jerking.

Demonstrate movement atthat speed.

o When you see thejerking begin,immediately stopmoving the stimu-lus and hold itsteady at thatposition.

o With the stimulusheld steady, look atthe eye and verifythat the jerking iscontinuing.

o If the jerking is notevident with thestimulus heldsteady, you havenot located thepoint of onset. Therefore, resumemoving the stimu-lus slowly towardthe side until younotice the jerkingagain.

Point out that nystagmusdoesn't go away once the eyestops moving. If the officeractually has found the point ofonset, the eye will continue tojerk when the stimulus is heldsteady.


HS 178 R1/02 VIII-28

o When you locatethe point of onset ofnystagmus, youmust determinewhether it is priorto 45 degrees.

- Verify thatsome white isstill showing inthe corner ofthe eye.

- Examine thealignmentbetween thestimulus andthe edge of thesuspect'sshoulder.

o Start moving thestimulus towardsthe left side (righteye) at the speedthat would takeapproximately 4seconds for thestimulus to reachthe edge of thesuspect's shoulder.

Demonstrate stopping thestimulus, and holding itsteady.

o As you are slowlymoving the stimu-lus, watch the eyecarefully for anysign of jerking.

Demonstrate movement atthat speed.

o When you see thejerking begin,immediately stopmoving the stimu-lus and hold itsteady at thatposition.


HS 178 R1/02 VIII-29

o With the stimulusheld steady, look atthe eye and verifythat the jerking iscontinuing.

Point out that nystagmusdoesn't go away once the eyestops moving. If the officeractually has found the point ofonset, the eye will continue tojerk when the stimulus is heldsteady.

o If the jerking is notevident with thestimulus heldsteady, you havenot located thepoint of onset. Therefore, resumemoving the stimu-lus slowly towardthe side until younotice the jerkingagain.

o When you locatethe point of onset ofnystagmus, youmust determinewhether it is priorto 45 degrees.

- Verify thatsome white isstill showing inthe corner ofthe eye.

- Examine thealignmentbetween thestimulus andthe edge of thesuspect'sshoulder.


HS 178 R1/02 VIII-30



o Stimulus initiallypositioned approxi-mately 12-15 inches(30-38 cm) in frontof student-subject'snose, slightlyhigher than eyelevel.

Station the student-subject ina position where student'seyes can readily be seen bythe class. (It may benecessary to conduct thedemonstration at two or morelocations.)

o Slowly move thestimulus toward theside, watching theeye for nystagmus.

o Stop the stimulusand hold it steadywhen nystagmus isfirst observed.


o Verify that the jerk-ing is continuing.

o Now determinewhether the onsetof nystagmus isprior to 45 degrees.

- is there whitestill showing inthe corner ofthe eye?

- is the stimuluswithin or onlyslightly beyondthe edge of theshoulder?

Solicit students' questionsconcerning the proceduralmechanics for Clue No. 3.


HS 178 R1/02 VIII-31



Remind students to movestimulus slowly.

o Coaching andcritiquing studentspractice.

Instruct each student topractice conducting the testfor onset of nystagmus priorto 45 degrees, using anotherstudent as the subject.

Common mistakes to note andcorrect.

o Incorrect position ofstimulus.

o Moving stimulus too fast.

o Student-leddemonstration.


7. Training Aid: The 45 DegreeTemplate

a. A training aid has beenprovided to help youpractice estimating a 45degree angle.

b. The outline of a square,with its diagonal line, givesus a 45 degree angle.

Instruct students to removetheir copies of the templatefrom their student manuals. NOTE: See Attachment Afollowing Slide VIII-35 - The45 Degree Template.

c. This outline, or template,is provided for practiceonly.

Demonstrate properplacement of the template.

It is not to be used with actualDWI suspects.


HS 178 R1/02 VIII-32

d. To use the template, haveyour training partner holdthe corner of the squareunder the nose.

Demonstrate placement of thepencil or penlight.

e. When you line up yourstimulus with the diagonal,your partner will belooking along a 45 degreeangle.

8. Student practice with 45degree Template.

a. Practice in groups of two orthree, taking turns.

Instruct students to begin bylining the stimulus up withthe diagonal, so they canbecome familiar with theposition of an eye at a 45degree angle.

Point out the amount of whiteshowing in the corner of aneye at 45 degrees.

Next, instruct each student toattempt to locate the 45degree point without usingthe template, then to raise thetemplate to check theaccuracy of the estimate.

b. Coaching and critiquingstudents' practice.

Common initial mistakes tonote and correct:

o Failing to check for white inthe corner of the eye.

o Failing to check alignmentof object with shoulder.

o Tending to stop short of 45degrees.


HS 178 R1/02 VIII-33

c. Student-led demonstration. Choose a student who appearsto be doing a good job inestimating a 45 degree angle,and have the student comeforward to demonstrate to theclass.

Resume student practice, andallow it to continue until allstudents appear reasonablyproficient in carrying out themechanics of Clue No. 3.


9. Test Interpretation.

a. Based upon the originaldevelopmental researchinto Horizontal GazeNystagmus, the criterionfor this test is 4.

b. If a person exhibits at least4 out of the possible 6clues, the implication is aBAC above 0.10.

c. Using this criterion, thetest is 77% accurate.

Note: Remind students thatthe SFST field evaluationstudy conducted in San Diegoin 1998 indicated that “HGNalone can provide validindications to support arrestdecisions at 0.08 BAC.”

10. Test Demonstration. Choose a student to serve as ademonstration subject.

Conduct a complete test ofthat student-subject,articulating every step in thetesting sequence (slide VIII-15should be redisplayed duringthis demonstration).

Upon completion of thedemonstration, solicit stu-dents' questions concerningHorizontal Gaze Nystagmus.


HS 178 R1/02 VIII-34

If time permits, conductanother complete demonstra-tion of HGN, using anotherstudent.

5 Minutes

D. Vertical Gaze Nystagmus


1. The Vertical Gaze Nystagmustest is easy to administer.

o Position the stimulushorizontally, approxi-mately 12-15 inches (30-38cm) in front of the subject'snose.

o Instruct the subject to holdthe head still, and followthe stimulus with the eyesonly.

Point out that verticalnystagmus was not examinedin the original research thatled to the validation of theStandardized Field SobrietyTest battery (Horizontal GazeNystagmus, Walk-and-Turnand One-Leg Stand).

o Raise the stimulus untilthe subject's eyes areelevated as far as possible. Hold for approximately 4seconds.

Select a student or anotherinstructor to serve as a subjectand demonstrate the verticalnystagmus test.

o Watch the eyes closely forjerking as they are movedup and are held in theupmost position.

2. Vertical Gaze Nystagmus maybe present in subjects underthe influence of high doses ofalcohol for that individual, andsome other drugs.


HS 178 R1/02 VIII-35

45 Minutes

E. Walk-and-Turn


1. Review of Divided AttentionDefinition.

Selectively display overhead.

a. Walk-and-Turn is a fieldsobriety test based on theimportant concept of divided attention.

Pose this question: "What do we mean by'divided attention'?"

Lead the discussion, as theseitems were previouslyidentified in Session VII.

b. The test requires thesuspect to divide attentionamong mental tasks andphysical tasks.

c. The mental tasks includecomprehension of verbalinstructions; processing ofinformation; and, recall ofmemory.

d. The physical tasks includebalance and coordination;the suspect is required tomaintain balance and coor-dination while standingstill, walking, and turning.

Remind students that prior toadministering this test, askthe subject if they have anyphysical problems ordisabilities.

2. Test Stages

a. The Walk-and-Turn testhas two stages, theinstructions stage and thewalking stage.


HS 178 R1/02 VIII-36

b. Both stages are essentialparts of the test.

c. Important evidence ofimpairment often comes tolight during both stages.

3. Test Requirements

a. The test requires thesuspect to take nine heel-to-toe steps in a straightline; to turn around in aprescribed manner; and, toreturn nine heel-to-toesteps along the line.

b. This test should beconducted on a reasonablydry, hard, level, non-slippery surface.

NOTE: Standardizing this testfor every type of roadcondition is unrealistic. Theoriginal research studyrecommended that this test beperformed on a dry, hard,level, nonslippery surface andrelatively safe conditions. Ifnot, the researchrecommends: 1) suspect beasked to perform the testelsewhere; or 2) only HGN beadministered. However,recent field validation studieshave indicated that varyingenviron-mental conditionshave not affected a suspect’sability to perform this test.

c. The line should be longenough to permit thesuspect to take nine heel-to-toe steps along it.

NOTE: Suspects with heels 2"or higher should be given theopportunity to remove theirfootwear.

d. If a line is not available,the officer may create aline.

NOTE: If no line exists, itacceptable to have a suspectwalk an imaginary line.

4. Demonstration of theInstructions Stage.

When demonstrating theinstructions stage, it is veryimportant that the studentsbe able to see the instructor'sfeet. It may be necessary todemonstrate at severallocations in the classroom.


HS 178 R1/02 VIII-37

Remind students ofofficer safetyprecautions.

o weapon side awayfrom suspect

o never turn back onsuspect

o aware of surround-ings (environment)

a. FOR STANDARDIZATIONPURPOSES, instructsuspects to place left footon the line first.

Demonstrate placement ofboth feet.

b. Then instruct suspects toplace their right foot on theline, ahead of the left foot,with heel of right againstthe toe of left.

c. Tell suspect to place armsdown at sides.

Demonstrate placement ofarms at sides.

d. Stress that suspect is tomaintain that positionuntil you have completedthe instructions.

e. Inform suspect not to beginwalking until told to do so.

f. At this point, ask suspect: “Do you understand?”

g. Although this position isnot a stance that peoplenormally will take of theirown choosing, it is notdifficult for an unimpairedperson to maintain thisstance, even for severalminutes.

Emphasize that officer mustreceive some affirmativeresponse before continuing.


HS 178 R1/02 VIII-38

h. People who are impairedcan maintain this stance ifthey concentrate their fullattention on it.

i. When you are with asuspect who appears to beimpaired, you may see thefollowing behaviors duringthe instructions stage.

NOTE: An impaired personcannot concentrate their fullattention on maintaining thestance. They also have tolisten to and comprehend yourinstructions.

o Fail to maintain heel-to-toe stance.

Demonstrate.

o Starts walking beforecommanded.

Demonstrate.

j. Impaired suspects mayconcentrate so much onmaintaining balance thereis little or nocomprehension of thesubsequent instructions.

Instructor may break awayfrom the heel-to-toe stance atthis point.

5. Demonstration of the WalkingStage.

A straight line must beavailable for this andsubsequent demonstrations.

A 10-12 foot strip of maskingtape on the floor of the class-room will prove suitable.

a. Walking stage requiresnine heel-to-toe steps alongthe line, a turn, and ninesteps back along the line.

b. While walking, keep thearms at the sides, count thesteps out loud, and keepwatching the feet.


HS 178 R1/02 VIII-39

c. Execute Walk-and-Turn. Instructor's demonstration. (repeat if necessary)


6. Walk-and-Turn AdministrativeProcedures

a. Initial verbal instructions

o Tell suspect to assumethe heel-to-toe stance(left foot on line, thenright foot on line, aheadof left).

Selectively reveal majorsections of overhead.

NOTE: FOR STANDARDI-ZATION PURPOSES, suspectis told to place left foot on linefirst, then right foot on line,ahead of left in a heel-to-toeposition.

o Tell suspect to placearms down at sides.

o Tell suspect not to startwalking until told to doso.

o Make sure suspect un-derstands instructions.

b. Description of basic testrequirements.

o Tell suspect to takenine heel-to-toe stepson the line, to turnaround, keeping onefoot on the line, and toreturn nine heel-to-toesteps.

Stress that officersshould never turn theirbacks on suspects whiledemonstrating. Instead,they should walk at rightangle to the line, keepingthe weapon away fromthe suspect.

o Demonstrate what youmean by walking heel-to-toe. (3 steps sufficefor the demonstration)

c. Description of turnprocedures.


HS 178 R1/02 VIII-40

o Tell suspect that, onthe ninth step, keep thefront foot on the line,and turn by takingseveral small stepswith the other foot.

NOTE: This turn procedure isprovided in order tostandardize the turndescribed in the study and forsuspects’ safety.

o Demonstrate the turnfor the suspect.

Stress that, when demon-strating the turn, officersshould stand at rightangle to the line with thesuspect to their left. Then, they can turn onthe left leg without everturning their backs tothe suspect.

NOTE: Difference for left-handed officers.

d. Final verbal instructions.

o Tell suspect that, whilewalking, to watch feetat all times.

o Tell suspect to keeparms at sides at alltimes.

o Tell suspect to countsteps out loud.

NOTE: The final verbalinstructions are provided tofurther standardizeadministration of the testdescribed in the study.

o Tell suspect that, oncethe walking begins, notto stop until the test iscompleted.


HS 178 R1/02 VIII-41

o Ask if suspect under-stands the instructions.Point out that, if sus-pect doesn't under-stand some part of theinstructions, officershould repeat only thatpart which suspectdoesn't understand.

Solicit students' questionsconcerning the Walk-and-Turn administrativeprocedures.

Select a student to participateas a subject in thedemonstration.

7. Demonstration of Walk-and-Turn AdministrativeProcedures.

Use precise language to directthe student-subject to assumethe instructions stance.

a. Tell the student-subject toassume the instructionsstance.

b. Tell the student-subject notto start walking until toldto do so.

Make sure directions areunderstood.

c. Tell the student-subject ofthe requirement to takenine heel-to-toe steps, toturn, and to take anothernine heel-to-toe steps.

Demonstrate severalheel-to-toe steps.

d. Tell the student-subject ofthe required turnprocedures. Demonstratethe proper turn.

Demonstrate the turn.

e. Give the student-subjectthe final verbalinstructions:

o Keep watching feet o Count steps out loud o Arms at sides o Don't stop walking

until test is completed.


HS 178 R1/02 VIII-42

f. Ask student-subject ifinstructions areunderstood.

Clarify any parts that are notunderstandable.

At this point, do not instructthe student-subject to executethe test. Rather, thank thestudent-subject forparticipating and allow thestudent to return to the seat.

Solicit students' questionsconcerning the testadministrative procedures.


8. Clues for Walk-and-Turn Test

a. When administering theWalk-and-Turn test, welook for certain specificbehaviors, at certain timesin the test.

Selectively reveal majorsections of overhead.

b. Each behavior, or action, isconsidered as one clue.

c. There is a maximum ofeight clues on this test.

d. The first two clues arechecked during theinstructions stage.

Reveal the first major sectionof slide VIII-21.

o Can't balance duringinstructions.

Emphasize that this clue isrecorded only if the feetactually break apart.

Note: During the instructionsstage, do not record the cluesimply because suspect raisesarms or wobbles slightly.


HS 178 R1/02 VIII-43

Demonstrate actions that con-stitute "can't balance duringinstructions", and demon-strate other actions that donot justify recording this clue.

o Starts too soon. Emphasize that this clue can'tbe recorded unless suspectwas told not to start walkinguntil directed to do so.

Stress to the students thatthese first two clues, like allclues in this test, can beaccumulated only once.

Example: if the suspect losesbalance twice during theinstructions stage, it still onlyconstitutes one clue.

However: on the standardnote taking guide, record howmany times each clue wasobserved.

e. The next four clues arechecked while the suspectis walking, either up ordown the line.

Reveal the next major sectionof slide VIII-21.

o Stops while walking(pauses to regainbalance).

Emphasize that it is becauseof this clue that it isimportant to inform thesuspect not to stop walkingonce the test begins.

o Misses heel-to-toe.

o Steps off the line.

Point out that a gap of at leastone-half inch is necessary torecord this clue.


HS 178 R1/02 VIII-44

o Uses arms to balance. Point out that a movement ofthe arms of six or more inchesfrom the side is required torecord this clue.

Demonstrate each of theseclues.

Point out that it is oftenpossible to note two of theseclues simultaneously.

Examples: (Demonstrate)

o pauses while walking andsimultaneously raises arms.

o misses heel-to-toe andsimultaneously stopswalking.

Reveal the next item on slideVIII-21.

f. The next clue is animproper turn. This clueshould be recorded if thesuspect:


o Loses balance on turn(staggers, stumbles,etc.); or,

o Turns other than theway officerdemonstrated.

Demonstrate various ways of"turning incorrectly" (i.e.,pivots, spins).

g. The next clue is checked onthe basis of the number ofsteps that the suspectactually takes.



HS 178 R1/02 VIII-45

o If the suspect takesother than nine steps,in either direction, it isconsidered only oneclue.

Emphasize that it is the num-ber of steps that the suspectphysically takes that mattershere. Mistakes in the verbalcount do not justify recordingthis clue.

h. The test may be terminatedif the suspect cannot safelycomplete it. For example:

Reveal the last item on slideVIII-21.

o Suspect steps off theline three or moretimes.

o Suspect nearly falls.

NOTE: If suspect can't dotest, record as if all eightclues were observed.

o Suspect gets into a "leg-lock" position (legscrossed, unable tomove)

Demonstrate "leg-lock".

Emphasize that the testshould be stopped if unsafe forthe suspect.

Solicit students' questionsconcerning the Walk-and-Turn clues.


9. Walk-and-Turn TestInterpretation

a. Based on the originaldevelopmental researchinto the Walk-and-Turntest, the criterion for thistest is 2.

b. If a person exhibits at least2 out of the possible 8clues, the implication isthat the suspect has a BACabove 0.10.


HS 178 R1/02 VIII-46

c. Using that criterion, thistest is 68% accurate.

d. Restrictions. NOTE: The originalresearch indicated thatindividuals over 65 yearsof age had difficultyperforming this test.

10. Test Demonstrations Choose a student to serve as ademonstration subject.

Conduct a complete test of thestudent-subject, carefullycarrying out all of the admini-strative procedures. (SlideVIII-20 should be redisplayedduring the demonstration.)

Have the student-subjectactually perform the walkingstage of the test.

Discuss the student-subject'sperformance in terms of thetest scoring factors. (SlideVIII-25 should be redisplayedduring this discussion.)

If time permits, conductanother demonstration usinganother student-subject.

5 Minutes

F. Combining the Clues ofThe Horizontal GazeNystagmus and Walk-and-Turn.


HS 178 R1/02 VIII-47

1. Based on the original researchyou will be 80% accurate inclassifying suspects that areabove 0.10.

NOTE: A combination of fouror more clues of HGN and twoor more clues of the Walk-and-Turn, suspects can becorrectly classified as above0.10 BAC 80% of the time.

35 Minutes

G. One-Leg Stand


1. Review of Divided Attentiondefinition

a. One-Leg Stand is anotherfield sobriety test thatemploys divided attention.

Selectively display slide.

b. The suspect's attention isdivided among such simpletasks as balancing, listen-ing, and counting out loud.

c. Although none of these isparticularly difficult initself, the combination canbe very difficult forsomeone who is impaired.

Remind students that prior toadministering this test, checkif the subject has any physicalproblems or disabilities.

2. Test Stages.

a. Like all divided attentiontests, One-Leg Stand hastwo stages.

b. They are the instructionsstage and the balance andcounting stage.

c. Both stages are important,because they can affect thesuspect's overallperformance on the test.

Selectively display remainderof slide.


HS 178 R1/02 VIII-48

3. Test Requirements.

a. The test requires thesuspect to stand on one leg,with the other leg held outstraight, approximately sixinches (15 cm) off theground, for 30 seconds.

b. This test should beconducted on a reasonablyhard, dry, level, and non-slippery surface.

Demonstrate the One-LegStand.

NOTE: Standardizing this testfor every type of roadcondition is unrealistic. Theoriginal research studyrecommended that this test beperformed on a dry, hard,level, nonslippery surface andrelatively safe conditions. Ifnot, the researchrecommends: 1) suspect beasked to perform the testelsewhere; or 2) only HGN beadministered. However,recent field validation studieshave indicated that varyingenvironmental conditionshave not affected a suspect’sability to perform this test.

4. Demonstration of theInstructions Stage.

a. The Instructions stage ofthis test is quite simple.

Remind students ofofficer safetyprecautions.

o suspect stands withfeet together.

o suspect keeps arms atthe sides.

b. Suspect is instructed tomaintain that positionuntil told otherwise.

5. Demonstration of balance andcount stage.


HS 178 R1/02 VIII-49

a. The verbal instructions forthis test also are quitesimple.

Point out that the officer mustdemonstrate the stance.

o Suspect is told to raiseone leg (either leg thatthe suspect chooses),approximately sixinches (15 cm) off theground, keeping footpointed out.

o Suspect is told to keepboth legs straight.

o Suspect is told to lookat the elevated foot.

o Suspect is told to holdthat position whilecounting out loud in thefollowing manner: “onethousand and one, onethousand and two, onethousand and three,and so on, until told tostop.”

POINT OUT THE NEEDTO TIME THE 30-SECOND COUNT. Stoptest at end of 30 seconds.

Point out that the 30 secondsconstitute an importantfeature of the test. Manyimpaired persons canmaintain balance for 20-25seconds, but seldom for up to30.

The suspect may be told atany time to stop counting fortheir safety or inability toproperly perform the test.


6. One-Leg Stand AdministrativeProcedures.

a. Instructions stage.

o Stand with feettogether.

o Keep arms at side.

Selectively display slide.


HS 178 R1/02 VIII-50

o Maintain position untiltold otherwise.


b. Balance and countingstage.

o Raise one leg, eitherleg.

o Keep raised legapproximately 6 inches(15 cm) off the ground,foot pointed out.

Selectively display slide VIII-24A.

o Keep both legs straight.

o Keep eyes on elevatedfoot.

o Count out loud fromone-thousand-and-one,one-thousand-and-two,one-thousand-and-three, and so on untiltold to stop.

NOTE: Officer should alwaystime the 30 seconds. If thesuspect puts their foot downtoo soon, tell suspect to keepfoot elevated and continuecounting. If suspect countstoo slow, stop the test at 30seconds.

7. Demonstration of the One-LegStand AdministrativeProcedures.

a. Instructions stage: tellsubject to:

o stand with feettogether

o keep arms at side

o maintain that positionuntil told otherwise(ask if understands)


HS 178 R1/02 VIII-51

b. Balance and counting stage

o Raise one leg (eitherleg), approximately 6inches (15 cm) off theground, foot pointedout.

o Keep both legs straight.

o Keep eyes on elevatedfoot.

o While holding thatposition, count out loudin the followingmanner: one-thousand-one, one to one-thousand-two, one-thousand-three untiltold to stop.

Always ask subject if theyunderstand directions beforebeginning test.


8. Clues for the One-Leg Stand.

a. When administering theone-leg stand test, we lookfor certain specificbehaviors.

Selectively reveal contents ofslide.

b. Each behavior or action isconsidered one clue.

c. There is a maximum num-ber of 4 clues on this test.

Reveal the first item on slide.

d. The first clue is swaying. Emphasize that swayingmeans a distinct, noticeableside-to-side or front-to-backmovement of the elevated footor of the suspect's body.


HS 178 R1/02 VIII-52

Slight tremors of the foot orbody should not beinterpreted as swaying.

Demonstrate swaying.

e. The next clue is using thearms to balance.

Reveal the next item on slide.

Point out that a movement ofthe arms of six inches or morefrom the side is sufficient torecord this clue.

Demonstrate using the armsto balance.

f. The next clue is hopping. Reveal the next item on slide.

Demonstrate hopping.

g. The next clue is putting thefoot down, before 30seconds elapse.

o If suspect’s foot touchesground, have suspectraise it and continuecounting until told tostop.

Reveal the next item on slide.

Demonstrate putting the footdown.

Emphasize some suspectscount slowly and may stand onthe leg for more than 30seconds. If suspect iscounting slowly, terminate thetest after 30 seconds havepassed.

Point out that it is possible tonote two cluessimultaneously.

Examples (Demonstrate): o hopping and swaying o foot down and arms raised.


HS 178 R1/02 VIII-53

h. The test may be terminatedif the suspect cannot safelycomplete it. For example:

Reveal the last item on slide.

o Suspect puts foot downthree or more times.

NOTE: Record as if all fourclues were observed.

o Suspect nearly falls.


9. Test Interpretation.

a. Based on the originaldevelopmental research forthe One-Leg Stand test, thecriterion for this test is 2.

b. If the person exhibits atleast 2 out of the possible 4clues, the implication isthat the suspect's BAC isabove 0.10.

c. Using that criterion, thistest is 65% accurate.

d. Restrictions. NOTE: The originalresearch indicated thatindividuals over 65 yearsof age or 50 pounds ormore overweight haddifficulty performing thistest.

10. Test Demonstrations. Choose a student to serve as ademonstration subject.

Conduct a complete test of thestudent-subject, carefullyarticulating the verbalinstructions.


HS 178 R1/02 VIII-54

Discuss the student-subject'sperformance in terms of thetest scoring factors. (SlideVIII-30 should be redisplayedduring this discussion.)

If time permits, conductanother demonstration usinganother student-subject.

5 Minutes

H. Limitations of the ThreeTests.

1. Nystagmus limitations.

a. A small percentage ofpeople may exhibitnystagmus, due to certainpathological disorders.

b. Some suspects may exhibitHorizontal Gaze Nystag-mus due to the use ofalcohol and certain otherdrugs.

c. A small percentage ofindividuals may exhibitnatural nystagmus.

2. Divided Attention testlimitations.

a. Both the Walk-and-Turn

test and the One-Leg Standtest require a reasonablysmooth, level surface.

b. Persons with injuries totheir legs, or inner ear dis-orders, may have difficultywith these tests or withother balance tests.


HS 178 R1/02 VIII-55

20 Minutes

I. Taking Field Notes on theStandardized Field SobrietyTests

1. For purposes of the arrest re-port and courtroom testimony,it is not enough to report thenumber of clues on the threetests.

a. The numbers are importantto the police officer in thefield, because they helpdetermine whether there isprobable cause to arrest.

b. But to secure a conviction,more descriptive evidenceis needed.

c. The officer must be able todescribe how the suspectperformed on the tests, andwhat the suspect did.

2. The standard note-takingguide is designed to helpdevelop a clear description ofthe suspect's performance onthe tests.

Instruct the students to takeout a copy of the note-takingguide to follow along with thisdiscussion.


3. The section on the pre-arrestscreening appears at thebottom of the guide's frontside.

a. Complete the entireprocedure for both eyes,checking "yes" or "no" foreach clue.

This slide will be left ondisplay throughout thediscussion.


HS 178 R1/02 VIII-56

o Check "yes" if the clueis present

NOTE: For standardization,test the suspect's left eye first.

Then, check for the same cluein the right eye.

o Check "no" if the clue isnot present

Emphasize that officers mustbe careful to place their checkmarks in the columnscorresponding to the eyeactually being checked.

b. After both eyes have beencompletely checked, totalthe number of HGN cluesobserved.

Point to this item on slideVIII-27. Remind students thatthe "number" of clues is usedonly for administrative pur-poses and that for courtroomtestimony a complete descrip-tion of each clue is essential.

c. In the section labeled"other", record any facts,circumstances, conditionsor observations that may berelevant to this procedure.

o Examples of additionalevidence of impairmentemerging whilechecking fornystagmus:

Point to this item on slideVIII-27.

Give examples of facts,circumstances, etc., thatshould be noted in this sectionof the note-taking guide (i.e.,Resting Nystagmus).

- suspect unable tokeep head still;

- suspect swayingnoticeably;

- suspect uttersincriminatingstatements.

Ask students to giveadditional examples offacts, circumstances,etc., that should be

noted.


HS 178 R1/02 VIII-57

o Examples of conditionsthat may interfere withsuspect's performancewhile checking fornystagmus:

- wind, dust, etc.(irritating suspect'seyes);

NOTE: Always face suspectaway from flashing or strobelights.


4. The section on the Walk-and-Turn test appears at the top ofthe guide's back side.

a. First two clues are checkedonly during theinstructions stage.

This slide will be left on dis-play throughout thediscussion of Walk-and-Turnscoring.

Point to the first two clues onslide VIII-28.

o In the boxes providedwrite number of timesthe clue appears duringthe instructions stage.

NOTE: Checks (T) may beused to denote number ofclues. However, always writetotals (numerically) in box.

o Example: if suspectloses balance twiceduring the instructionsstage, write "2" in thatbox.

Remind students that the clue"loses balance during instruc-tions" is recorded only if thesuspect's feet "break apart".

o Example: if the suspectdoes not start too soon,write "0" in that box.

Emphasize that students arenever to leave a box blank: ifthe clue doesn't appear, theymust indicate that by writing"0".

b. Record the next four cluesseparately for each ninesteps.

Point to these items on slideVIII-28.


HS 178 R1/02 VIII-58

c. If suspect stops walking,record it by drawing avertical line across the toeat the step at which thestop occurred. Do this foreach nine steps.

Instruct students to place aletter “S” at bottom of verticalline to indicate “stopswalking”.

o How many timesduring first nine steps;

o How many timesduring second ninesteps.

Remind students that, ifsuspect stops walking evenonce, that will count as oneclue; but in order to prepare aclear, descriptive arrestreport, it is best to documenthow many times suspectpaused while walking.

d. If suspect fails to touchheel-to-toe, record howmany times this happens.

e. If suspect steps off the linewhile walking, record it bydrawing a line from theappropriate footprint atthe angle in the directionin which the foot stepped. Do this for each nine steps.

f. If suspect uses arms tobalance, give someindication of how often orhow long this happens.

Instruct students to place theletter “M” at the bottom ofvertical line to indicate“misses heel to toe”.

o Example: suspectraised arms from sidesthree times;

Place three T (check marks) inthe box.

o Example: suspect heldarms away from sidesduring steps 3 through7;

Write "steps 3-7" in box.


HS 178 R1/02 VIII-59

o Example: suspect"flapped" armscontinuously.

Write in box.

g. Record the actual numberof steps taken by suspect,in each direction.

Point out that Slide VIII-28states "actual steps taken".Wrong number of steps is thevalidated clue.

h. For the next clue, "theturn," record a descriptionof the turn.

o Example: turnedincorrectly;

o Example: stumbled, toleft;

o Example: wrongdirection;

o Example: no smallsteps.

i. If you terminate the testbecause the suspect"cannot perform test",indicate why.


o Example: off line 3times;

o Example: staggered sixsteps to right, nearlyfell;

NOTE: Stop test for fear ofinjury to suspect.

o Example: "leg-locked"after fifth step.


HS 178 R1/02 VIII-60

j. At end of the test, examineeach factor and determinethe total number of cluesrecorded.

Remind students that,even if a clue shows upmore than once, eachclue is counted onlyonce.

k. In the section labeled"other", record any facts,circumstances, conditionsor observations that may berelevant to this test.


o Examples of additionalevidence of impairmentemerging during Walk-and-Turn test:

- suspect verballymiscounts steps;

Give examples of facts,circumstances, etc., thatshould be noted in this sectionof the note-taking guide.


o Examples of conditionsthat may interfere withsuspect's performanceof the Walk-and-Turntest:

- wind/weatherconditions;

- suspect's age;

- suspect's footwear.

Ask students to giveadditional examples offacts, circumstances,

etc., that should be noted.



HS 178 R1/02 VIII-61

13 20

Type of Footwear


5. The section on the One-LegStand test appears midwaydown the page.

a. Record the suspect'sperformance separately.

b. For each clue, record howoften it appears.

This slide will be left on dis-play throughout thediscussion of one-leg standclue.

Point out that, by recordingwhen things happen as well aswhat happens, a moredescriptive arrest report canbe prepared.

c. If suspect sways, indicatehow often with a checkmark.

d. Indicate above the feet thenumber they were countingwhen they put their footdown.

e. Check marks should bemade to indicate thenumber of times thesuspect swayed, used arms,hopped or put foot down.

o Place check marks in ornear the small boxes toindicate how manytimes you observedeach of the clues. Inaddition, if the suspectputs the foot downduring the test, recordwhen it happened. Todo this, write the countnumber at which thefoot came down.

Demonstrate the proper docu-mentation for observed clues.


HS 178 R1/02 VIII-62

For example, supposethat, when standing onthe left leg, the suspectlowered the right footat a count of "one thou-sand and thirteen," andagain at "one thousandand twenty;" Yourdiagram should looklike the sketch to theright.

d. If suspect uses arms tobalance, indicate how oftenarms were raised.

e. If suspect hops, indicatehow many hops weretaken.

f. If suspect puts foot down,indicate how many timesthe foot came down.

g. If you terminate the testfor "cannot perform test",indicate explicitly why youdid so.

o Example: foot down 3times;

o Example: staggeredthree steps to right,then fell;


o Example: continuoushopping, flailing arms,nearly falling.


HS 178 R1/02 VIII-63

h. At end of the test, examineeach clue and determinehow many clues have beenrecorded.

Remind students that, even ifa clue shows up more thanonce, each clue is counted onlyonce.

i. Write the number in the"total clues" box.

Point to this item on slideVIII-29. Remind studentsthat "number" of clues isutilized only foradministrative purposesand that for courtroomtestimony a completedescription of each clueobserved is essential.

j. In the section labeled"other", record any facts,circumstances, conditionsor observations that may berelevant to this test.


o Examples of additionalevidence of impairmentemerging duringone-leg stand test:

Ask students to giveadditional examples offacts, circumstances,etc., that should be

noted.

- suspect verballymiscounts 30seconds;


Give examples of facts,circumstances, etc., thatshould be noted in this sectionof the note-taking guide (i.e.,untied shoelaces, removedfootwear, etc.).

o Examples of conditionsthat may interfere withsuspect's performanceof one-leg stand:

- wind/weatherconditions;


Solicit students' questionsconcerning field note taking.


HS 178 R1/02 VIII-64

- suspect's age;

- suspect's footwear.

session viii concepts and principles of the …session viii concepts and principles of the...

Documents