Abstracts

Following reports of a syndrome of reversible parkinsonism with normal [beta] CIT [ndash]SPECT in patients exposed to sodium valproate(VPA) the authors wished to establish the prevalence of this symptom in people taking anti-epileptic drugs(AEDs) by means of a validated 11 item screening questionnaire for parkinsonism Three hundred and fifty six consecutive patients with epilepsy attending a tertiary epilepsy clinic(Hope Hospital) and a district general neurology clinic(Leigh Infirmary) were recruited. Patients with learning difficulties, progressive neurological conditions, history of previous head injury were excluded. Patients were asked to complete an 11 item validated questionnaire( sensitivity 84.4%, specificity 86.3%) designed to screen for parkinsonism. Forty-two controls were recruited from healthy relatives accompanying patients to the clinic and from hospital staff. Twenty-one patients diagnosed as having Parkinson[rsquo]s Disease(PD) (Presence of at least 2 of the following; resting tremor, bradykinesia, rigidity) were recruited. 356 patients completed the questionnaire, 75 were found to be taking/or have taken psychotropic or anti-emetic medication and were excluded from further analysis.
One hundred and thirty-two patients took one anti-epileptic(AED) drug only. There were no significant differences between the VPA, Carbamazepine(CBZ) or Lamotrigine(LTG) groups for age at time of study or duration of epilepsy. There were no significant difference for age between epilepsy patients and controls. Patients with PD were significantly older. A further 38 patients took VPA plus one other AED, 22 took LTG plus one other AED, 33 took CBZ plus one other AED.
Chi-square test of the three monotherapy groups showed no significant difference in the number of individuals with positive questionnaires suggesting the presence of parkinsonism between the three groups or when compared with the control group. Chi [ndash]square became significant when the Parkinsons Disease group PD was added to the analysis. When the duel therapy groups were combined with the monotherapy groups for the purpose of analysis there were no significant differences between the groups. Previous studies of the prevalence of parkinsonism in patients taking VPA suggest a rate of 6 per hundred as opposed to the age adjusted prevalence of parkinsonism of 1 in 500. This study which is the largest to date suggests the prevalence of parkinsonism in people exposed to VPA is not as high as previously thought. However it must be borne in mind that the present study[rsquo]s methodology is different from earlier studies and we have not as yet clinically examined all the participants. Further studies are required to explore the incidence and aetiology of this phenomenon.