BRIEF COMMUNICATI.ON

EEG Abnormalities in Tourette's SyndromeFRED R. VOLKMAR, M.D., JAMES F. LECKMAN, M.D., JILL DETLOR, R.N., DIANE F. HARCHERIK, M.S.,

JAMES W. PRICHARD, M.D., BENNETT A. SHAYWITZ, M.D., AND DONALD J. COHEN, M.D.

Electroencephalographic (EEG) abnormalities in a series of 45 patients with Tourette'ssyndrome were related to clinical and historical factors in this study. Twenty-one of the 45tracings (47%) exhibited abnormalities; the most common abnormalities noted includedsharp waves and slowing. A posterior focus of abnormal activity was noted in 16 cases.Subjects with an earlier age of onset were significantly more likely to have abnormal EEGs.

Journal of the American Academy of Child Psychiatry, 23, 3:352-353, 1984.

Tourette's syndrome (TS) is a chronic, neuropsy­chiatric disorder of childhood onset. Although multi­ple motor and phonic tics are prominent aspects ofthe disorder, attentional disturbances are commonly'associated with the syndrome as well (Cohen et al.,1980). Family history studies are suggestive of a he­reditary component in many cases (Kidd et at, 1980).

In his original description of the syndrome, Gillesde la Tourette (1885) emphasized the organic natureof the illness. A neurological basis for the disorder hasbeen suggested by the relatively high frequency ofbirth difficulties, neurological findings, and abnormalelectroencephalograms (EEG) which have been ob­served to range from 27% to 86% of TS cases (Shapiroet al., 1973). While the proportion of TS patients whoexhibit EEG abnormalities is markedly higher thanthat of the general population, no consistent patternof abnormality has yet been identified. In this paperwe report the results of an investigation of a series ofpatients with TS in which EEG findings are relatedto a variety of historical and clinical factors in an

Fred R. Volkmar is Assistant Professor of Psychiatry and Pedi­atrics and William T. Grant Foundation Faculty Scholar, Yale ChildStudy Center. James F. Leckman is Assistant Professor of Pediatricsand Psychiatry and Donald J. Cohen is Professor of Pediatrics,Psychiatry and Psychology, Yale Child Study Center. Jill Detlor isClinical Nurse Coordinator and Diane Harcherik is an Associate inResearch at the Child Study Center. James W. Prichard is AssociateProfessor in Neurology, Yale University and Bennett A. Shaywitz isAssociate Professor 9fPediatrics and Neurology, Yale University.

This research was supported in part by MHCRC Grant MH 30929,NIH Grant HD 03008, Children's Clinical Research Center GrantRR 00125, the William T. Grant Foundation, and the GatepostsFoundation.

We appreciate the collaboration of the staffof the Yale-New HavenHospital EEG Laboratory and the Children's Clinical Research Cen­ter.

Reprints may be requested from Dr. Cohen, Child Study Center,.333 Oedar St., New Haven, CT 06510.

.0002-7138/84/2303-0352 $02.00/0 © 1984 by the American Acad­emy of Child Psychiatry.

attempt to define factors related to EEG abnormali­ties.

Method

Subjects

Forty-five patients (42 male and 3 female) comprisethe sample. Patients ranged in age from 6 to 49 yearswith a median age of 11 years and a mean age of 14.8years (S.D. = 9.14). Diagnosis of TS was based onDSM-III criteria. Eleven of the cases had been in­cluded in a previous analysis of EEG patterns ofneuropsychiatrically disturbed children (Waldo et al"1978).

Each patient, or the patient's parent, had completedthe Yale Tourette Syndrome Questionnaire (TSQ)(Jagger et al., 1982). The TSQ is designed to collect awide variety of demographic and clinical data includ­ing medical and family history, developmental andschool history, age of onset of TS, severity and naturalhistory of TS symptoms, and responsiveness to med­ications.

Procedure

EEG tracings were obtained by two techniciansexperienced in working with children with develop­mental disturbances. Eight bipolar recordings weremade simultaneously from the frontal, temporal, pa­rietal, and occipital areas of both hemispheres (re­spectively). EEGs were interpreted by board certifiedelectroencephalographers, blind to diagnosis, using astandard multidimensional rating scale (Waldo et al.,1978). Interpretations were prepared for analysis usinga standard coding form (Waldo et al., 1978).

The rater noted for each recording a global assess­ment of the EEG (Gibbs and Gibbs, 1964). The pri­mary and secondary voltage, abnormal features, sei­zure activity, focus of any abnormal activity, responses

352

EEG ABNORMALITIES IN TOURETTE'S SYNDROME 353

Results

Discussion

In this study we examined the relationships betweenclinical variables and EEG findings in patients withTS. As in previous studies TS patients were found to

to hyperventilation, and photic stimulation were alsorecorded.

For purposes of statistical analysis subjects withnormal and probably normal EEGs were grouped asthe "normal" EEG group while subjects with abnor­mal, or borderline EEGs composed the "abnormal"group.

EEG Profiles

Abnormal EEGs were noted in 25 of the 45 cases.Results of the interpretation of the recordings aresummarized in Table 1. The most common abnormal­ities noted were sharp waves (18 cases) and slowing(12 cases). Single abnormal features were noted in 13cases and two abnormalities were observed in 12 ofthe cases. Seizure discharges were not observed. Aposterior focus of abnormal activity was observed in16 cases; in 3 of these cases the focus was noted to beright posterior and in 1 case left posterior.

Clinical and Historical Correlates

There were no significant differences between thenormal and abnormal EEG groups across a broadrange of 12 demographic and clinical variables includ­ing birth complications, history of head injury, familyhistory of TS, responsiveness to medications, age ofonset of TS, and severity of TS symptoms. Only ageof onset of TS was significantly related to abnormal­ities in the EEG. Children with abnormal EEGs weresignificantly more likely to have experienced an earlieronset of TS symptoms, 5.9 years for the abnormalEEG group and 7.7 years for the subjects with normalEEG tracings (Mann-Whitney U test, Z = 1.84, df =1, P < 0.05). Neither the presence or location of sharpwaves nor of slowing in the EEG record was signifi­cantly related to specific historical factors, includingage of onset.

ReferencesCOHEN, D. J., DETLOR, J., YOUNG, J. G. & SHAYWITZ, B. A.(1980),

Clonidine ameliorates Gilles de la Tourette syndrome. Arch. Gen.Psychiat., 37:1350-1357.

GIBBS, F. A. & GIBBS, E. L. (1964), Atlas of Electroencephalography,Vol. III. Reading, Mass.: Addison-Wesley.

GILLES DE LA TOURETTE, G. (1885), Etude sur une affection ner­veuse, characterisee par de !'incoordination motrice accompagneed'echolalie et de coprolalie. Arch. Neurol., 9:158-200.

JAGGER, J., PRUSOFF, B. A., COHEN, D. J., KIDD, K K., CARBON­ARI, D. M. & JOHN, K A. (1982), The epidemiology of Tourette'ssyndrome: a pilot study. Schizo. Bull., 8:267-278.

KIDD, K K, PRUSOFF, B. A. & COHEN, D. J. (1980), Familialpatterns of Gilles de la Tourette syndrome. Arch. Gen. Psychiat.,37:1336-1339.

LONEY, J., LANGHORNE, J. E. & PATERNITE, C. K (1978), Anempirical basis for subgrouping the hyperkinetic/minimal braindysfunction syndrome. J. Abnorm. Psychol., 87:431-441.

LUCAS, A. R., KAUFFMAN, P. E. & MORRIS, E. M. (1967), Gilles dela Tourette's disease: a clinical study of fifteen cases. This Jour­nal, 6:700-722.

SHAPIRO, A. K, SHAPIRO, K, WAYNE, H. & CLARKIN, J. (1973),Organic features in Gilles de la Tourette syndrome. Brit. J.Psychiat., 122:659-644.

WALDO, M. C., COHEN, D. J., CAPARULO, B. K, YOUNG, J. G.,PRICHARD, J. W. & SHAYWITZ, B. A. (1978), EEG profiles ofneuropsychiatrically disturbed children. This Journal, 17:656­670.

have a markedly elevated incidence of EEG abnor­malities. These abnormalities included, most com­monly, the presence of sharp waves and slowing. Ageof onset was significantly earlier in patients withabnormal EEG tracings. Otherwise no specific histor­ical or clinical factors were observed to discriminatethe two groups. The EEG did not appear to be ofeither clinical or prognostic significance with thissample, apart from the findings of an earlier age ofonset of TS in those subjects with EEG abnormalities.The persistence of immature .patterns in EEGs ofthese patients is of theoretical interest as it may implysome maturational delay in development of the cere­bral cortex. However, earlier reports have not reportedany particular relationship between age of onset of TSsymptoms and EEG abnormalities. (Lucas et al., 1967;Shapiro et al., 1973). Given the number of compari·sons employed in this study there is a possibility thatthis is a chance association. If this association can bereplicated in prospective studies, additional work inthis area, possibly involving the developmental courseof EEGs and event related potentials, may be indi­cated in children at high risk to develop TS. Anincreased incidence of EEG abnormalities has beenreported in other childhood onset psychiatric illnessesand we have previously reported evidence for distinc­tive clusters of EEG abnormalities in several diagnos­tic groups (Waldo et al., 1978). In that study, as inthis one, no specific abnormality served as a diagnosticmarker, which suggests the utility in future studies ofmultivariate techniques to relate EEG patterns tounderlying symptom, demographic, and historical di­mensions (Loney et al., 1978).

2025948211o

No. ofCases

TABLE 1

Summary of EEG Profiles

Profile

NormalAbnormal

Sharp waves aloneSlowingSharp waves + slowingPhotoconvulsive dischargePolyspikesIncreased cerebral excitabilitySeizure discharge