motor and psychological functions of school children living in the area of the skrunda radio...

8/8/2019 Motor and Psychological Functions of School Children Living in the Area of the Skrunda Radio Location in Latvia

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the Science of theTotal EnvimnmentThe Science of the Total Environment 180 (1996) 87-93

Motor and psychological functions of school children livingin the area of the Skrunda Radio Location Station inLatviaA.A. Kolodynski*, V.V. Kolodynska

Institute of Biology, La trian Academy of Scien ces, 3 Miera Str., Sala spils, LV-2121, Latvia

AbstractThis paper presents he resultsof experimentson schoolchildren living in the area of the Skrunda Radio LocationStation (RLS) in Latvia. Motor function, memory and attention significantly differed between the exposedandcontrof groups.Children living in front of the RLS had lessdevelopedmemory and attention, their reaction time wasslower and their neuromuscular pparatusendurancewasdecreased.

Keywords: Electromagnetic ield; Adolescent; Motor reaction; Memory; Attention

1. IntroductionAn early warning military radio location station(RLS) has operated for more than 25 years in apopulated region of Skrunda, Latvia. However,the study of chronic effects of electromagneticradiation on the population at Skrunda has onlyrecently started. Studies of motor and psychologi-

cal development of children and adolescents thatlive close to the RLS may provide evidence ofeffects.The Skrunda RLS is an pulse radar station thatoperates at frequencies of 154-162 MHz. Theduration of pulses is 0.8 ms and time betweenpulses is 41 ms, i.e. the pulses occur at a fre-

* Correspondinguthor

quency of 24.4 Hz [3,7]. The electromagnetic field(EMF) effect of this frequency range on humanmotor and psychological function is insufficientlystudied, however, there are already data availableon the inhibiting effects of EMF [2,5,6,8]. Theliterature indicates that EMFs may influence hu-man motor and psychological processes [5,91.This report summarises the results of a study ofthe development of some motor and psychologi-cal functions of children who were born andconstantly live under conditions of chronic EMFexposure in the Skrunda area.2. Materials and methods2.1. Subjects and groupsThe studies were performed on 966 children(425 males and 541 females) aged 9-18 years. A

004%9697/96/$15.00 0 1996 Elsevier Science BV. All rights reserved.SSDI 0048-9697(95)04924-P


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88 A.A. Kolodynski, VV. Kolodynska / The Scien ce of the Total Environment 180 (1996) 87-93total of 689 c&l&en were examined in the Kuldfgaand Saidus regions within a 20-km radius of theSkrunda RLS. Of these, 224 pupils live in directlyexposed areas. The Skrunda RLS is located in avalley, and the exposed population lives on theslope in the direction of the field of view of thestation (westward). Exposure decreases with dis-tance from the radar [3], and field intensitiesbehind the radar are background levels. The con-trol group of 357 pupils lived in the Preili region.Girls and boys were divided into five age groupswith 2-year intervals (Table 1).

Polytest-8802 is a specialised computer that usesreaction to determine human functional state. Intotal, 11 tests were used for each child. A restbreak was included and the test duration was 70min. Each test included twenty measurements,which were used to obtain the arithmetical mean,standard deviation and standard error of the mean[41.2.2. Tapping-test

According to the Ministry of Environment Pro-tection and Regional Development of Latvia, bothof these regions have similar and low pollutionlevels (Table 2) [l]. Both are agricultural, withoutmajor point sources of pollution, with the excep-tion of small boiler houses.

To evaluate the functional state of the neuro-muscular system, we used a tapping-test. Thechildren examined had to press two keys withtheir right and left hands at maximum rate for 30s. The rate of key pressing per second was regis-tered for each hand separately.2.3. Reaction timeFor the populations of children living in frontof the radar and behind it, and for the control

group, groups of similar age and sex were se-lected. We examined similar social groups offarming communities, and 95% of subjects livedon small farms. The tests were carried out in thespring, from April to May.

The studies were performed with a psychophys-iological diagnostic system Polytest-8802. The

Red light diodes were used to present lightstimuli at the centre of the table and on the leftand right sides. The visible diameter of the lightwas 2.5 mm and the stimulus duration wa s 40 ms[4]. Sound stimuli were given with stereo ear-phones (intensity, 60 dB; stimulus duration, 100ms; frequency, 1 kHz). The interval between bothlight and sound stimuli wa s randomised (2.5-4 s>.The children had to rapidly press and release keys

Table 1Mean age f S.E. (years) of five groups of children from the Skrunda area, further classified into unexposed and exposed, and thePreih region (control group

RegionAge group (years)9-10 11-12 13-14 15-16 17-18

Skrunda, unexposedFemalesnMalesnSkrunda, exposedFemales,,Males12Prei\i, controlFemalesIIMales!,

9.7 f 0.1 11.5 f 0.1 13.7 f 0.1 15.3 f 0.1 17.4 f 0.131 73 49 41 239.8 f 0.1 11.4 & 0.1 13.5 f 0.1 15.3 * 0.1 17.3 f 0.130 64 35 31 8

9.6 _+0.1 11.4 * 0.1 13.7 + 0.1 15.1 ZL0.1 17.6 of: .114 26 40 41 179.6 ?r.0.1 11.4+0.1 13.4 f 0.1 15.3 f 0.1 1719 20 22 24 19.7 i- 0.1 11.5 * 0.1 13.7 + 0.1 15.3 * 0.1 17.4 * 0.126 53 49 38 209.4 + 0.1 11.3 i 0.1 13.5 * 0.1 15.4 * 0.1 17.5 + 0.125 54 47 30 1.5 -.


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A.A. Kolodynski, V.V. Kolodynska / The Scien ce of the Total Environment 180 (1996) 87-93 89Table 2Estimated rates of emissions (tons/km*) from all sources in Kuldiga and Preili districts in 1991Region Particles SO2 co TotalKuldiga 790.1 1052.8 80.7 571.5 2496.2Preili 1250.7 2011.4 352.3 1195.8 4818

after stimuli. Presentation of stimuli from thetable centre or biaurally (RTB) required the childto press both buttons simultaneously. When thestimulus was presented from the side of the table(RTL.), or in one earphone, the subject had topress the key on the side corresponding to thestimulus. In the cross variant of the test (RTC),the subject had press the key at the side oppositethat of the stimulus. The response time, durationof press contact and the number of errors wereregistered.2.4. AttentionThe capacity for attention switching was testedaccording to a modified Shultes procedure. Theprocedure used a double-coloured table of 64squares. Each square consisted of two numbers:large black colour and small red (index), as wellas a response button. At the beginning of the testthe monitor displayed a number which the childwas required to find among the black numbers.When the required black number wa s found, thechild was required to press the appropriate keyand memorise the associated red number. Thisnew number was then searched for among theblack numbers and the process was repeated 20times.The stability and capacity to focus attentionwere studied with an entangled lines test. Thetest table was covered with entangled lines. Eachline began with a number on the left side andfinishes with another number on the right side.The child was required to rapidly fol low each linevisually and press the button at its finish. Thetime taken to fol low every line and the number oferrors were registered.2.5. MemoryMemory was tested by the capacity to remem-ber numbers. During one test, three numbers

were displayed on a monitor at l-s intervals. Thechild then entered the three numbers on thekeyboard. This wa s repeated seven times, progres-sively increasing the number of numbers dis-played from three to nine. The volume of opera-tive memory was determined according to theformula V = A + (m/n> where A is the largestnumbers of digits in the operation which wassuccessfully reproduced by the child in all experi-ments, II is the number of experiments, m is thenumber of correctly reproduced number series,During the experiment, a series of numbers ofincreasing complexity was presented, beginningwith three digits and ending with nine. Whitedigits of 6 x 10 mm, on a dark-grey backgroundwere presented on the computer monitor.

2.6. StatisticsStatistically significant differences were evalu-ated by Students criteria for quantitative vari-ables.3. Results

Preliminary data analysis showed that amonggrade 9 children, there were 16% fewer boys inSkrunda, and 25% fewer in the area exposed tothe Skrunda RLS. This is uncommon in Latvia forGrade 9 school children and the reasons for thesedifferences are not known. The rates of all motorreaction (tapping-test and reaction time) tests inboys were better than in girls, both in exposedand control groups, and hence male and femalegroups were treated separately.The reaction time to both sound and visualstimuli in the children living around Skrunda wassomewhat longer than in Preili children, for bothgirls and boys, although the differences are statis-tically significant only for younger groups (Fig. 1).The duration of retention of keys in the pressed


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90 A.A. Kolodynski, V. V. Kolodynska / The Scien ce of fhe Total Enr!ironment 180 (1996) 87-93h 600g SW

9 to 10 11 to 12 13 tu 14 15 tu 16 17 to 18A G E G R 0 lJ P S (years)

Fig. 1. Means f standard errors of the cross response lefthand reaction time CRT) to sound stimuli in children (female)in five age groups from Skrunda ( +) and PreiQ ( n ). For ages9-10 and 11-12 years, the differences are significant at P


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A.A. Kolodyn ski, V. V. Kolodynska / The Scien ce of the Total Enuironment 180 (1996) 87-93 91

Ykruoda Skrunda Yreiliexposed unexposed control

Fig. 3. Means k standard errors of operative memory in maleand female children aged 15-16 years, living in the Skrundaexposed and unexposed areas and the Preili control area. Thedifferences are significant (P < 0.05) between the Skrundaexposed and unexposed areas, as well as between the Skrundaunexposed and Preili areas.

human electroencephalogram P-rhythms, and itis not excluded that low frequency pulses are oneof the reasons for the observed alterations. Lyskovet al. [5] showed that low-frequency magneticfields induced inhibition of motor and nervousprocess. Our earlier research [41 also demon-strated that a weak low frequency pulse EMFcauses shifts in neurophysiological parameters,even after 15 min.The weak correlations between the distancefrom the childrens homes to the RLS, and thechildrens responses, are certainly consistent withthe idea of an electromagnetic field effect. The

Skrunda Skrunda Prei(i controlexposed unexposed

Fig. 4. Means f standard errors of time of attention switch-ing test duration in male and female children aged 15-16years , living in the Skrunda exposed and unexposed areas andthe Preili control area. The differences are significant (P


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92 A.A. Kolodynski, V. V. Kolodynska / The Scien ce of the Total Environment 180 (1996) 87-93Table 3Mean values f S.E. of retention time of keys in the pressed state for right hands by male and female children from the Sknmdaunexposed area and Sknmda exposed area, in reaction to sound stimuli presented biaurally and monaurally

RegionAge groups (years)9-10 11-12 13-14 15-16 17-18

Biaural stimuli (RTB)FemaleUnexposedExposedP-valueMalesUnexposedExposed

P-value

214 f 10250 f 11< 0.05206 it 8258 f 12< 0.05

164*13228 f 15< 0.01128+8182 f 14< 0.01

1261t7167 f 10< 0.05191 f 9211 f 10

NS182k9223 + 11

< 0.05145 f 11200*8

< 0.01105*7156 f 9

< 0.0599+ 6124 f 10

NSMonoaural stimuli (RTLJFemaleUnexposedExposedP-valueMaleUnexposedExposedP-value

224 f 9265 f 11< 0.05220 f 10239 + 11< 0.05

221 * 11249 f 16NS173 f 10219 f 15< 0.05

192 f 10224 f 10< 0.05212 + 10243 f 11< 0.05

208f9227 i 10NS202 f 11210&9NS

190 f 12202 * 11NS110 f 12133 f 11NS

Cross variant of test (RTC)Female

UnexposedExposedP-valueMaleUnexposedExposedP-value

209If: 11259 f 14< 0.05197*a238 f 10< 0.05

221 f 11246fll< 0.05199 f 11237 f 12< 0.05

222 f 10239 f 11< 0.05175 f 8207 f 11NS

199 * 9232 f 10< 0.05200*11221 f 8NS

170 f 7191 f 9NS199 f 10181 f 9NS

RTL, key pressed at same side as stimulus; RTC, key pressed at opposite side as stimulus; NS, not significant.of the radiation zone, and the temporal changesin intensity are high [3]. However, the resultspresented, especially the weak correlationbetween performance and distance to the RLS,certainly suggest that this path of research isworthwhile. Further work is continuing to in-crease the sample size and to attempt to arrive atestimations of dose.

for logistical help during the project. Financialassistance wa s obtained from the Latvian ScienceCouncil Project Nr. 136.69.References

[ll Ministry of Environment Protection and Regional De-velopment, Air environment protection, Report for 1991,Riga, 1992, pp. 54.[2] H.A. Hansson, E ffec ts on the nervous system by exposureto electromagnetic fields: experimental and clinical stud-ies, in M.E. OConnor and R.H. Lovely (Eds.) Electro-magnetic Fields and Neurobehavioral Function. Progressin Clinical and Biological Research, Vol. 257, Alan R.Liss Inc., New York, 1988, pp. 119-134.[3] T. KalnirJS, A. Krisbergs, A. Romanchks, Measurement of

AcknowledgementsThe authors extend their thanks to G. Briimelis

for improving the language of the text, and to I.Nunkvica, a teacher at the Skrunda 1 High School,


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AA. K olodynski, V.V. Kolodynska / The Scien ce of the Total Envimnment 180 (1996) 87-93 93the intensity of electromagnetic radiation from theSkrunda radar, Sci. Total Environ., 180 (1996) 51-56.[4] Kolodynski A. Human Psychophysiological Reaction toLateralized Signals Under Monotony Conditions, AVKPress, Riga, 1993, pp. 48 p.[5] E. Lyskov , J. Juutilainen, V. Jousmaki, J. Partanen, S.Medvedev and 0. Hanninen, Effect of 45-Hz magneticfield on the functional state of the human brain. Bioelec-tromagnetics, 14 (1993) 87-95.[6] S. Medvedev, E. Lyskov, Z. Alecsanian, V. Iousmiaki, J.Jutilainen, 1. Partanen, I. Rutkovskaja, T. Safonova and0. Khaninen, Dynamics of brain bioelectric act ivi ty and

reaction t ime after exposure to an alternating magneticfield. Fiziol. Cheloveka, 18 (1992) 41-48.[7] Air Material Command of the Royal Danish Air Force,Report: Non-Ionising Radiation Measurements aroundthe Russian Radar Site in Skrunda, Latvia, Skrunda,1994.19 pp.[8] A. Novini , Fundamental issues on electromagnetic fields .Acupunct. Electrother. Res., 18 (1993) 23-31.[9] M. OConnor, Psychological studies in non-ionizing elec-tromagnetic energy research. J. Gen. Psychol., 120 (1993)33-47.

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