The precentral P22/N30 cortical component of the median nerve somatosensory evoked potentials (SEPs) was recorded in 16 patients (11 women and five men) suffering from cervical dystonia before and after botulinum toxin therapy. Cervical dystonia was diagnosed as idiopathic in all patients: 13 patients suffered from right-sided torticollis, and three suffered from left-sided torticollis. The amplitude of the P22/N30 component and the side-to-side ratio of amplitude values were measured. Normal values were obtained by acquiring measurements in two groups of healthy volunteers (n1 = 20 and n2 = 20). The recordings in the first control group were done with the patient's head in a normal position, whereas, in the second control group, the patient kept the head intentionally rotated 60 degrees to the right. Patients were treated with local injections of botulinum toxin A (BTX-A). The mean duration of treatment was 8.3 months, and the mean total amount of BTX injected was 295 U. The P22/N30 precentral component was repeatedly recorded in patients after head posture had been corrected to the normal plane by BTX-A treatment. The recordings showed that the amplitude of the P22/N30 precentral component recorded contralaterally to the direction of head deviation was significantly higher in patients before treatment than after treatment. Contralateral pretreatment amplitudes were also significantly higher (p < 0.01 and p < 0.05, respectively) than amplitudes in both groups of healthy volunteers. The mean side-to-side ratio of precentral P22/N30 component amplitudes was significantly higher in patients before treatment compared with after treatment and also compared with both control groups. These changes in dystonic patients probably reflect the direction of head rotation, the muscle pattern of torticollis, and the change in force of dystonic contraction after the treatment. The changes presumably could be the result of higher excitability of the precentral cortex contralateral to head rotation in patients with cervical dystonia and its change after successful BTX-A treatment.

Results from a dose-ranging study in a selected group of de novo patients with rotational cervical dystonia (CD) suggest that 500 units of Dysport (Clostridium botulinum toxin type A haemaglutinin complex) is the optimal starting dose. The present study aimed to confirm the efficacy and safety profile of this dose in a population of CD patients more representative of those seen in a typical dystonia clinic. A total of 68 patients with moderate to severe CD (Tsui score > or = 9) were randomly assigned to receive placebo or Dysport 500 units. Treatment was administered according to the clinical pattern of head deviation, using a standardised injection protocol. A total of 21 patients (11 Dysport, 10 placebo) had not previously received botulinum toxin type A (BtxA) injections, and 47 patients (24 Dysport, 23 placebo) had received BtxA more than 12 weeks previously. Assessments were performed at baseline and weeks 4, 8 and 16. Patients defined as non-responders at week 4 were re-treated in an open phase with 500 units of Dysport at week 6, and were followed up at week 10. Significant between-group differences in Tsui scores were present at weeks 4 (p=0.001) and 8 (p=0.002). Similarly, there were significant between-group differences (p < 0.001) in patient and investigator assessments of response in favour of Dysport at weeks 4 and 8. Also, more Dysport (49%) than placebo (33%) patients were pain-free at week 4 (p=0.02). Overall, 30/35 (86 %) Dysport patients and 14/33 (42%) placebo patients were classified as responders at week 4. Adverse events were reported by 15/35 Dysport patients and 9/33 placebo patients. Open phase treatment produced improvements in Tsui (p < 0.001) and pain scores (p=0.011), and 23/24 patients were classified as responders. Although individual dose titration and muscle selection is desirable, this study demonstrated that a dose of 500 units of Dysport injected into clinically identified neck muscles without electromyographic guidance is safe and effective in the treatment of patients with the major clinical types of cervical dystonia.

Twelve patients with levodopa-induced dyskinesias were treated with continuous subcutaneous apomorphine. A markedly significant reduction in peak dose dyskinesias occurred over a two-year follow-up.

We studied cognitive functions related to processing sensory and motor activities in the basal ganglia (BG), specifically in the putamen and in cortical structures forming the BG-frontocortical circuits. Intracerebral recordings were made from 160 brain sites in 32 epilepsy surgery candidates. We studied P3-like potentials in five different tests evoked by auditory and visual stimuli, and two sustained potentials that are related to cognitive activities linked with movement preparation: BP (Bereitschaftspotential) and CNV (contingent negative variation). We compared the presence of a potential with a phase reversal or an amplitude gradient to the absence of a generator. All of the studied cognitive potentials were generated in the BG; the occurrence in frontal cortical areas was more selective. The frequency of all but one potential was significantly higher in the BG than in the prefrontal and in the cingulate cortices. The P3-like potentials elicited in the oddball paradigm were also more frequent in the BG than in the motor/premotor cortex, while the occurrence of potentials elicited in motor tasks (BP, CNV, and P3-like potentials in the CNV paradigm) in the motor cortex did not significantly differ from the occurrence in the BG. The processing of motor tasks fits with the model by Alexander et al. of segregated information processing in the motor loop. A variable and task-dependent internal organisation is more probable in cognitive sensory information processing. Cognitive potentials were recorded from all over the putamen. The BG may play an integrative role in cognitive information processing.

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