Effects on cognition of stereotactic lesional surgery for the treatment of tremor in multiple sclerosis.

OBJECTIVE: To assess the effect of stereotactic lesional surgery for treatment of tremor in multiple sclerosis on cognition. METHODS: Eleven patients (3 males, 8 females) with multiple sclerosis participated in the study. Six subjects comprised the surgical group and five the matched control group. All patients were assessed at baseline and three months using a neuropsychological test battery that included measures of intellectual ability, memory, language, perception and executive function. RESULTS: There were no significant differences between the surgical and control groups and no change from pre to post testing except for a decline in scores on the Mini-Mental State Examination (MMSE), WAIS-R Digit Span and Verbal Fluency in the surgical group. CONCLUSIONS: The results indicate that stereotactic lesional surgery does not result in major cognitive impairment in multiple sclerosis. However, the decline in MMSE scores, digit span and verbal fluency require further investigation in a larger sample.

A dominant bursting electromyograph pattern in dystonic conditions predicts an early response to pallidal stimulation.

Although chronic pallidal deep brain stimulation (DBS) is effective in the treatment of medically intractable dystonia, there is no way of predicting the variations in clinical outcome, partly due to our limited understanding of the pathophysiological mechanisms underlying this condition. We recorded electromyographic (EMG) activity from the most severely affected muscle groups in seven dystonia patients before and after pallidal DBS. Patient EMG recordings could be classified into two groups: one consisting of patients who at rest demonstrated a dominant low frequency component of activity on power spectral analysis (ranging from 2 to 5 Hz), and one group in which this dominant pattern was absent. Early postoperative improvements (within 2-3 days) were observed in the former group, whereas the latter group benefited more gradually (over several months). Analysis of EMG activity may provide a sensitive means of identifying dystonic patients who are likely to be most responsive to functional neurosurgical intervention.

Thalamotomy versus thalamic stimulation for multiple sclerosis tremor.

Disabling intractable tremor occurs frequently in patients with multiple sclerosis (MS). There is currently no effective medical treatment available, and the results of surgical intervention have been variable. Thalamotomy has been the mainstay of neurosurgical therapy for intractable MS tremor, however the popularisation of deep brain stimulation (DBS) has led to the adoption of chronic thalamic stimulation in an attempt to ameliorate this condition. With the goal of examining the relative efficacy and adverse effects of these two surgical strategies, we studied twenty carefully selected patients with intractable MS tremor. Thalamotomy was performed in 10 patients, with chronic DBS administered to the remaining 10. Both thalamotomy and thalamic stimulation produced improvements in postural and intention tremor. The mean improvement in postural tremor at 16.2 months following surgery was 78%, compared with a 64% improvement after thalamic stimulation (14.6 month follow-up) (P > 0.05). Intention tremor improved by 72% in the group undergoing thalamotomy, a significantly larger gain than the 36% tremor reduction following DBS (P < 0.05). Early postoperative complications were common in both groups. Permanent complications related to surgery occurred in four patients overall. Following thalamotomy, long-term adverse effects were observed in three patients (30%), and comprised hemiparesis and seizures. Only one patient in the thalamic stimulation group experienced a permanent deficit (monoparesis). We conclude that thalamotomy is a more efficacious surgical treatment for intractable MS tremor, however the higher incidence of persistent neurological deficits in patients receiving lesional surgery may support the use of DBS as the preferred surgical strategy.

Direct economic impact of Parkinson's disease: a research survey in the United Kingdom.

The direct costs of care were evaluated prospectively in a sample of people with Parkinson's disease (PD) in the United Kingdom in 1998. The subjects were drawn from a random sample of general practitioner practices within a representative sample of 36 Regional Health Authorities and the equivalent. A total of 444 resource use questionnaires with usable data were returned (response rate, 59%). The total mean annual cost of care per patient for all patients by age was 5,993 pounds (9,554 euro, n = 432). Hoehn and Yahr stage significantly (P < 0.001) influenced expenditure by stage as follows: 0 and I, 2,971 pounds (4,736 euro, n = 110); II, pound 3,065 (4,886 euro, n = 89); III, 6,183 pounds (9,857 euro, n = 120); IV, 10,134 pounds (euro;16,155, n = 87); V, 18,358 pounds (29,265 euro, n = 17). National Health Service costs accounted for approximately 38% and social services for 34% of the direct costs of care. Drug expenditure accounted for 24% of overall costs in the <65 years age group and 10% in patients aged >85 years. A move from home to residential care was associated with an approximately 500% cost increase. In conclusion, PD imposes significant direct costs on public services and on individuals. These costs should be taken into account when allocating public funds.