physiological and acoustic correlates of fluency and disfluency .pdf / kunnampallil gejo

7/27/2019 PHYSIOLOGICAL AND ACOUSTIC CORRELATES OF FLUENCY AND DISFLUENCY .pdf / KUNNAMPALLIL GEJO

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Early studies- breathing, motor capacities, and

heart rate

Turned to- investigations of the stutterers

- tissue chemistry

- neuromuscular organization- handedness

- cortical potentials

KUNNAMPALLIL GEJO JOHN, MASLPKUNNAMPALLIL GEJO JOHN


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- eventually led to research on more subtle aspects ofauditory perception

- lateral dominance for cerebral processing of speech.

Most physiological measures are responsive tomuscular effort and autonomic arousal.

KUNNAMPALLIL GEJO JOHN


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Cardiovascular Factors and Basal Metabolic Rate

McDowell (1928) compared stutterers and non stutterers inaverage heart rate and blood pressure and found no difference.

Travis, Tuttle, and Cowan (1936) observed faster heart ratesthan normal in stuttering subjects before and during speech.

Fletcher, attributed this chiefly to the emotional reactions andrespiratory abnormalities associated with stuttering.



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Ritzman (1943) found no differences between adultmale stutterers and their controls in heart rate, sinus

arrhythmia, blood pressure, and basal metabolic rate(BMR).

Among female stutterers, however, he found less marked

sinus arrhythmia and higher pulse pressure and basal metabolicrate than in their controls and a definite tendency for them toresemble the male stutterers in these measures.



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Biochemical Factors

For a brief period it appeared that clues in the etiology ofstuttering might be found in the chemical make-up of the

stutterers body.

Alveolar Carbon Dioxide and Salivary pH

Edwin B, found that the large majority of stutterers wereshallow breathers suffering from fatigue or lethargy broughton by insufficient aeration of their blood.



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Starr reasoned sub breathing stutterers - a lowsalivary pH as a consequence of their CO2 excess

the hyper excitable psychopath stutterers shouldhave low alveolar CO2 and high salivary pH.

Alveolar CO2 1

Salivary pH



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Trumperfound that oxygen deficit in the arterialblood results in a compensatory increase in thenumber and hemoglobin content of the red blood

cells. Studied 101 cases of stuttering & identified onethird as shallow breathers.

In blood studies of this group he found that there was

an increased red blood cell count and relatively highhemoglobin.



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Chemical Composition of the Blood

Kopp ( 1934 ) found that the blood chemistry of the stutterer was essentiallynormal. Differences were observed when compared with non-stutterers

Stutterers: higher in,

serum calciuminorganic phosphorusblood sugar

lower in,potassiumtotal protein

albuminglobulin

they seemed to differ as well in the degree of relationship between some ofthese components.



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Anderson and Whealdon (1941) found that stutterers did notdiffer from the general population in distribution of blood

types and therefore in the proteins controlling agglutination.

Lovett Doust (1956) reported stutterers to show more markedchanges than normals in oxygen saturation of capillary bloodin response to the stress of breath-holding and interpreted thisas a sign of less stable oxidative metabolism in the stutterers.

Rastatter and Harr (1988) measured neurotransmitter andamino acid blood levels and reported high levels of glutamine

in stutterers.



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Reflex Activities

Evidences of lability, sensitivity, or irritability of theautonomic nervous system in stutterers.

Sovak (1935) reported normal oculocardiac and

positive solar plexus reflexes in the majority of agroup of stuttering children and adults.



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Bruno, Camarda, and Curi (1965) foundelectronystagmographic abnormalities in 29 of 50stutterers.

Castellini, Salami and Ottoboni (1972) observed themin 14 of 30 cases. In none of these studies was a controlgroup used.

Siroky, Langova, Moravek, and Svab (1978), using acontrol group, found a considerably greater number ofsaddle-shaped nystagmic jerks in the records ofstutterers, whether in silence or speech.



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Neilson, Andrews, Guitar, and Quinn (1979) found nodifferences between 4 stutterers and 6 normalspeakers in stretch reflexes of the jaw closingmuscles.

Nine stutterers did not differ from controls in reflexchanges in biting force in response to loud noise andtactile stimulation of the lip, tongue, and teeth inresearch by Smith and Luschei (1983) and McFarland,Smith, Moore, and Weber (1986).



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Tremors

Herren (1932) found that during silence as well as speech arelatively rapid tremor, at the rate of 40 to 75 per second,occurred more frequently in the records of the stutterers.

Hill (1944) suggested that they might be traced in part to anincreased adrenalin output during stuttering.

McFarland, Smith, Moore, and Weber (1986) found nodifferences in amplitude of tremor of the jaw closing muscles assubjects exerted a constant force on a bite block insertedbetween upper and lower teeth.



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Muscular Tension

Travis and Fagan (1928) measured the resistance of thependant hand to 40-ounce blows.

They found that more resistance was offered by stutters thanby normal speakers during silence.

This might have resulted from either situational or chronic

nervous hypertension among the stutterers.

Shackson (1936) Faster muscle contraction - latent tetany.



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Brown and Schulman (1940) measured muscular

tension by determining the pressure needed to injecta minute amount of saline solution into the body ofthe biceps muscles.

They found no evidence that stutterers were tenser than nonstutterers.



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What is alpha wave?

Cerebral cortex was the site of concentration ofelectrical activity, or brain waves. One of

these, the alpha wave.



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Electrode

Placement

Brain Area Measures Conditions Results

Travis &

Knot

(1936)

Bipolar Left Visual

and

motor

Amplitude

duration

Silence,

speech

Found small differences

that they considered

difficult to interpret.The waves during the

nonstuttered speech of

stutterers were larger

and slower than those

for the speech of

normal speakers.

Cortical Potentials of Stutterers and Non

stutterers



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Moore and

Haynes

(1980)

Monopolar Left and

right

temporo-

parietal

Integrated

alpha

amplitude

Stimulation

by pure

tones and

speech

The stutterers

showed less

alpha in the

righthemisphere

than the non

stutterers

for both

verbal and

nonverbalstimuli.



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Moore and

Lorendo

(1980)

Mono

polar

Left and

right

temporo-

parietal

Integrated

alpha

amplitude

Auditory

presentation

of words

The non stutterers had

less alpha in the left

than the right

hemisphere; the

stutterers, just the

reverse.



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Moore

(1986)

Mono polar Left and

right

temporo-

parietal

Integrated

alpha

amplitude

Auditory

presentation

, recognition

and recall

of words

and

paragraph

material

The stutterers showed

right-hemisphere alpha

suppression; the non

stutterers, left-

hemisphere alpha

suppression.



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Cerebral Blood Flow

Pool and Watson (1991) found reduced blood flow in

the frontal lobes of 20 stutterers in recognizedcortical regions of speech-motor control, as well as inthe left temporal lobe.

They concluded that their findings suggest thatstuttering is a neurogenic disorder.


Journal articles


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Journal articles

Autonomic Correlates of Stuttering and Speech Assessed in

a Range of Experimental Tasks

[ Journal of Speech and Hearing Research Vol.33 690-706December 1990 ] Christine M. Weber & Anne Smith

Electro dermal activity, peripheral blood f low, and heart rate

were recorded from 19 stutterers and 19 normal speakersduring performance of jaw movements, a strenuous breath-holding task, reading, and spontaneous speech.

The tasks were selected to produce a range of autonomicactivation and thus help scale autonomic activation for speechrelative to other motor behaviors. Speaking was associated

with relatively large increases in autonomic activity in bothstutterers and normal speakers.

There were no differences between the two groups of speakers,suggesting that the stutterers did not have abnormally highlevels of autonomic activation in speech.



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Within the group of stutterers, the more extreme increases inarousal were correlated with the occurrence and increased

severity of disfluent speech.

Significant correlations were found for the intervals prior to,during, and after speech. Measures of autonomic arousalaccounted for small percentages of the variances of fluency and

severity.

The results are consistent with the hypothesis that sympatheticarousal accompanies the breakdowns in speech motor processescharacteristic of stuttering.



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CO ORDINATION BETWEEN ARTIULATORY AND

PHONATORY EVENTS:

Mis-coordinition.

VOT is a very useful measurement.

Watson (1982) - longer VOT has been reported in bothperceptually dysfluent speech and f luent utterances of

stutterers.



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Basu (1979) compared VOT of stutterers for voiced andvoiceless stop sounds of Kannada language inspontaneous reading and syllables.

Results showed that stutterers showed longer VOT forvoiced and voiceless stop in both reading and syllable.Consistent increase in VOT with respect to position ofarticulatory constriction was observed for stutterers.

According to Metz et al (1979), Revathi (1989) there wasno significant difference between VOT of stutterers andnon stutterers speech.



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CO ORDINATION BETWEEN ARTIULATORY ,

LARYNGEAL AND RESPIRATORY EVENTS:

Mis-coordinition.

Adams (1974) - fluency is dependent or smoothcoordination of activities of the respiratory, laryngeal,articulatory system.



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Mohan Murthy(1988), studied acoustic, aerodynamicand laryngeal correlates of stuttering. Measurement

was done through spectrograph, electroaerometerand electroglottograph respectively.

It was observed that inhalatory frictions of varyingduration, atypical CV and VC transition of vocal foldcycles and inappropriate timing .



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Raghunath on basis of descriptive analysis on different

spectrograms revealed the following errors-

Errors of aspiration

Errors of coarticulation

-lack of formant transition,

-longer transition time-shorter transition time

Addition/ interjection

Errors in manner of articulation

Error on place of articulation

Prolongation

Errors in aspiration and coarticulation

Errors of coarticulation and prolongation

Errors of coordination of articulatory and glottal gestures.KUNNAMPALLIL GEJO JOHN


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Respiration

Breathing Movements

Breathing abnormality was a cause of stuttering.

These anomalies are not present during silence. alsofound in the breathing of normal speakers during

speech, although not to the same degree.



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In studies of stuttering children and adolescentswithout controls, Schilling (1960, 1962) observedabnormal diaphragmatic movements during silentbreathing.

Moore (1938) and Kurshev (1968), found that duringsilence stutterers and non stutterers did not differ inmeasures of breathing movement.



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Breathing curves during stuttering show a series ofabnormalities like..

Antagonisms between abdominal and thoracic breathing

Irregularity of consecutive respiratory cycles

Prolonged expirations or inspirations

Complete cessation of breathing

Interruption of expiration by inspiration

Attempts to speak on intake of air.



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Phonation

Common clinical observations that point to the larynx as asite of abnormal activity during stuttering are.

Breath-holdingGlottal fryStutterers reports that their throat closes tightly

Chevrie-Muller (1963) studied vocal folds during stutteringby the technique of glottography.

Results showed many abnormalities includingbreaks in the rhythm of vocal fold vibration and aclonic fluttering of the folds in some but not all of herstutterers (cited by Van Riper, 1971)



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Janssen and Vaane (1983) studied 5 stutterers byusing glottographic recording to test the assumption

that stuttering blocks are associated with slowness ininitiating phonation, relative to the start ofarticulatory activity.

Among five subjects this proved to be true for onlytwo.



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Borden, Baer, and Kenney (1985) also noted evidenceof rigidity of the vocal folds during stuttering, as wellas tremors that coincided with visible tremors of thelip.

Bar, Singer and Feldman (1969) Electromyography

study showed an increase in the action potentials justbefore and during stuttering.



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Freeman and Ushijima (1975, 1978) tookelectromyographic recordings simultaneously from

intrinsic laryngeal muscles of four subjects.Results:High levels of muscular activity during stuttering, as well as

simultaneous contractions of adductor and abductor muscles.



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Conture, McCall, and Brewer (1977) used a fiber optictechnique during stuttering in ten subjects.

In 60 percent of thepart-word repetitions the vocalfolds were in a state of abduction throughout theblock, regardless of whether the repeated speechsegment was voiced or unvoiced.

Duringprolongations of sounds the position ofthe folds was always appropriate to the voicingcharacteristics of the sound.



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In a later fiber optic study, Conture, Schwartz, andBrewer (1985) found that during voiced prolongationsthe vocal folds were usually appropriately adducted,

but that during sound or syllable repetitions andvoiceless prolongations the folds were adducted,abducted, or in an intermediate position.

Their observations appeared to show that stutterersdo not simply squeeze their vocal folds togetherduring all instances of stuttering; the vocal folds maybe inappropriately adducted or abducted.



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Journal articlesLaryngeal Behavior during Stuttering

[Journal of Speech and Hearing Research Vol.28 233-240

June 1985. ]

Edward G. Conture & Goward D. Schwartz

The purpose of this study was to provide detailed, objectivedescriptions of stutterers' laryngeal behavior during instances ofstuttering within conversational speech. Subjects were 11 adultstutterers who produced stutterings (sound prolongations andsound/syllable repetitions) while their laryngeal behaviors were

observed by means of a flexible fiber-optic nasolaryngoscope(fiberscope). Laryngeal behaviors 8 of the 11 stutterers stutterings

were categorized as adducted, intermediate, or abducted.



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Results indicate that during sound prolongations the vocal

folds were more likely to be adducted and less variable in theirmovement than during sound/syllable repetitions.

Results further indicated that the voicing characteristics of thestuttered sound (voiceless vs. voiced) and the type of stuttering

(sound prolongation vs. sound/syllable repetition) interactivelyinfluenced laryngeal behavior.

It is hypothesized that a complex interaction among the

laryngeal, articulatory, and respiratory systems contribute tothe occurrence of the inappropriate abductory and/oradductory laryngeal behavior, which characterizes prolonged orrepeated (stuttered) speech segments.



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Articulation

Shaffer (1940) found that stuttering was characterized.

by longer time intervals between onset of jaw movement andonset of phonation,

by more directional changes in jaw movement,

by longer intervals between initiation and first directionalchange of jaw movement.



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In Electromyographic studies of the masseter muscles by Travis(1934), Morley (1937), Steer (1937), and Williams (1955) showed

that in stuttering there is frequent evidence of defectivesynchronization, as well as other abnormalities of the actionpotentials of the paired musculatures.

Sheehan and Voas (1954) used unilateral masseter actionpotentials to show that muscular tension appears to build upduring stuttering, reaching its peak near the termination of theblock.



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Shapiro (1980), four subjects with electrodes at the lip andtongue showed excessive muscular activity on stuttered words,poor coordination of muscles, and inappropriate bursts ofactivity during silence.

Craig and Cleary (1982) observed high levels of activity in theorbicularis oris in their three subjects during stuttering.

Kittel (1983) found excessive activity in the orbicularis oris andtongue in forty-two subjects.



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Smith (1989) correlated the activity of neck, jaw, and lipmuscles during stuttering.

She found little indication that the coordination of thesemuscles differed from that of normal speaking control subjects,but unlike any of the nonstutterers, 6 of 10 stutterers exhibited

large rhythmic oscillations in muscle activity during stuttering. These occurred at the same frequency in all of the muscle

groups, suggesting that they had a common source.

In the same muscles Smith, Denny, and Wood (1991) observedtremor like oscillations and increased activity which were nottimed precisely with perceived stutterings.



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Guitar, Guitar, Neilson and Andrews (1988). Inarticulating the initial p of the words peek, puck, andpack, the normal speakers typically activated the

depressor anguli oris before the depressor labiiinferior.

The stutterers reversed this sequence most of the time whenstuttering and half the time when not. The authors

hypothesized that the stutterers were deliberately stiffeningtheir lips in the expectation of stuttering.



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Aerodynamic Studies

Hutchinson (1975) identified 7 distinctive aerodynamicpatterns.

1. Repeated peaks in intraoral air pressure were associated withsyllable repetitions.

2. A gradual elevation of intraoral air pressure occurred withprolongation of a sound, especially a stop consonant.

3. Multiple elevations of intraoral pressure without airflow wereassociated with a silent block on a stop consonant.

4. Prolonged airf low terminating in an excessive peak of airflowcorresponded to a breathy articulation of a sound such as /w/

with an aspirated release.KUNNAMPALLIL GEJO JOHN


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5. A sudden drop in air pressure and flow rate accompanied abrief silent interval.

6. A prolonged peak of intraoral air pressure and absence ofairflow signified the silent prolongation of an articulatoryposture.

7. Intraoral pressure elevations of low magnitude withoutairflow were observed on a prolonged pause betweensyllables



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Spectrographic Studies

Van Riper (1971) speculated that the stutterers difficulty is notwith sounds but with the transitions between them (i.e.) moreof part-word repetitions.

But the neutral vowel is almost universally heard (e.g. suh-suh-sandwich) in place of the intended vowel that would be requiredby normal coarticulation.

Montgomery and Cooke (1976) found that stutterers part-wordrepetitions do not ordinarily contain the neutral vowel, but a

vowel that often approximates that of the word beingpronounced.



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Van Wyk (1978) reported an absence of formant transitions in

the repetitions of eighteen stuttering children and adults, butperceptual and spectrographic analysis showed that the neutral

vowel was not being used.

Stromsta and Fibiger (1981) found reduction of normalcoarticulation during stutterers sound repetitions. Spectrogramsand electromyographic recordings were made from the upper lipof stutterers while reading a passage weighted with syllables

revealing anticipatory coarticulation by labial movement (e.g.Europe, screw).The spectrograms showed less coarticulatory labial activity

during repetitions than on stutterers f luent utterances or normalspeakers utterances of the same words.



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Hutchinson and Watkin (1976) studied the jaw movementsof four stutterers at the terminations of blocks.

They found that the articulatory movement wasabnormally rapid at the moment of release from thestuttering block.

In addition, in a number of instances the movement of thejaw was not coordinated with the onset of vocalization,sometimes preceding and sometimes lagging behind it.



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Journal articles

SOME ACOUSTIC CORRELATES OF STUTTERING:

A PRE-POST THERAPY COMPARISON[ S. R. Savithri ,1987 ]

This study aimed at evaluating the efficacy of prolongation

therapy in establishing fluency by measuring acousticparameters in the pre post therapy samples of persons whostutter. Five persons who stutter (4 males and 1 female) inthe age group of 12 to 25 years participated in the

experiment. For spectrographic analyses, words in the pretherapy reading/ speech samples on which stutteringoccurred and the same words in the post therapy sampleswere used.



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RESULTS

The articulatory dis-co-ordinations included atypical/missingF2 transitions, errors in place and manner of articulations,production of nasal for nonnasals and vice-versa.

Three types of laryngeal dis-co-ordinations were identified (a)usage of murmur instead of voicing which was indicated by

voice bars superimposed by aspiration (b) absence of voicing invoiced sounds and (c) usage of voicing for unvoiced consonants

as indicated by the presence of voice bars for unvoicedconsonants. Aspiration was used for unaspirated stops, whichwas evidenced by the presence of low frequency noise.



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The word initial unaspirated stop /p/ was uttered as aspirated/ph/. Inspiratory frications were audible and were identified asfills on the spectrogram. Both these were classified asaerodynamic disco-ordinations. Not all types of disco-ordinations were noticed in all stutterers, indicating apossibility of sub grouping of stutterers. No articulatory dis-co-

ordinations were observed in the post therapy sample of anystutterer.

It appears that the prolongation therapy was successful ineliminating articulatory disco-ordinations and not the

laryngeal or the aerodynamic. It is possible that these disco-ordinations may be difficult to be eliminated or theprolongation therapy was not efficient in eliminating these orthe training was insufficient.



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The incomplete closure of the vocal folds for the voiced sounds(murmur) and the opening of the vocal folds (absence of

voicing) indicates difficulty in adjusting the laryngeal gestures.

Results indicated several articulatory, laryngeal andaerodynamic disco-ordinations. The data supports the notionthat stuttering is a disorder of disco-ordination in articulation,phonation and breathing.



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