[Therapeutical strategies for essential tremor]. / Estrategias terapéuticas en el temblor esencial.

Essential tremor is the most common adult movement disorder. Traditionally considered as a benign disease, it can cause an important physical and psychosocial disability. Drug treatment remains poor and often unsatisfactory. Current therapeutical strategies are reviewed according to the level of discomfort caused by tremor: mild tremor, non-pharmacological strategies, alcohol, acute pharmacological therapy; moderate tremor, pharmacological therapies (propranolol, gabapentin, primidone, topiramate, alprazolam and other drugs), and severe tremor, the role of functional surgery is emphasized (thalamic deep brain stimulation, thalamotomy). It is also described the more specific treatment of head tremor with the use botulinum toxin. Finally, several points are exposed to guide the immediate research of this disease in near future.

Usefulness of p300 in subjective memory complaints: a prospective study.

The existing studies about the utility of P300 latency for diagnostically classifying patients in preclinical stages of dementia are cross-sectional rather than longitudinal in design, and their results are inconclusive. The authors investigated the P300 value in a series of patients with subjective memory complaints using a prospective design. The study was performed in a consecutive series of 116 outpatients with subjective memory complaints as the predominant symptom. P300 (auditory oddball task) was performed immediately after the first clinical evaluation, and at 12 and 24 months. Final cognitive syndrome diagnosis (mean follow-up period, 27.7 months) was then made by a neurologist who was blinded to the neurophysiologic results. Diagnosis at the end of follow-up was 30 cases of normal cognition, 30 cases of mild cognitive impairment, 28 cases of dementia of Alzheimer's type (DAT), five cases of vascular dementia, and one case of frontotemporal dementia; 22 patients were lost to follow-up. P300 latency was significantly higher for the DAT group (analysis of variance: P=0.023) throughout the study. The diagnostic value of P300 latency at baseline examination for DAT had a sensitivity of 52.9% and a specificity of 76.9%; the odds ratio was 3.75 (95% confidence interval, 1.23-11.41). Findings from the present study suggest that assessment of evoked related potentials may contribute to the early detection of DAT.

Effects of pallidotomy and bilateral subthalamic stimulation on cognitive function in Parkinson disease. A controlled comparative study.

Unilateral pallidotomy and bilateral subthalamic deep brain stimulation (STN-DBS) for Parkinson's disease (PD) have demonstrated a positive effect on motor functions. However, further studies are needed of the unintended cognitive effects accompanying these new surgical procedures. We studied the consequences of unilateral pallidotomy and STN-DBS on cognitive function in a controlled comparative design. Sixteen consecutive PD patients were assessed before and 6 months after unilateral pallidotomy (n = 8) and bilateral STN-DBS (n = 8). The same assessments were performed in a control group of eight non-operated matched PD patients recruited from surgery candidates who refused operation. The neuropsychological battery consisted of test measuring memory, attention, arithmetic, problem solving and language, as well as visuospatial, executive and premotor functions. An analysis of variance (factors time and treatment) was applied. No statistically significant differences were found in the presurgical evaluation of clinical and demographic data for the three treatment groups. The controlled comparison between presurgical and postsurgical performance revealed no significant changes in the cognitive domains tested in the pallidotomy group. The STN-DBS group showed a selective significant worsening of semantic verbal fluency (p = 0.005). This controlled comparative study suggests that neither unilateral pallidotomy nor bilateral STN-DBS have global adverse cognitive consequences, but bilateral STN-DBS may cause a selective decrease in verbal fluency.

Transcranial magnetic stimulation of the cerebellum in essential tremor: a controlled study.

BACKGROUND: Growing evidence implicates an overactivity of the cerebellum in the pathophysiology of essential tremor. In a small series of patients, we explored the acute effects and therapeutic possibilities of low-frequency repetitive transcranial magnetic stimulation (rTMS) of the cerebellum in patients with essential tremor in a double-blind, crossover, placebo-controlled design. METHODS: Ten patients with essential tremor underwent an active and a sham rTMS session, at a 1-week interval. The rTMS was performed with a focal double 70-mm butterfly coil (maximum peak field of 2.2 T) applied 2 cm below the inion. Each session consisted of 30 trains of 10-second duration separated by 30-second pauses, at 100% of the maximum output intensity and at 1-Hz frequency. Major evaluation outcomes were the score on the Tremor Clinical Rating Scale and accelerometric recordings obtained before (-5 minutes), immediately after (+5 minutes), and 1 hour after (+60 minutes) each rTMS session. Both clinical and accelerometric measurements were obtained by a blinded neurologist. RESULTS: On the +5-minute assessment, active rTMS produced a notable tremor improvement compared with sham rTMS, as evidenced by a significant reduction in scores on the clinical rating scale and accelerometric values. At +60 minutes, no clinical or accelerometric benefit was evidenced. No adverse effects of rTMS were observed. CONCLUSIONS: This exploratory study of the potential therapeutic properties of rTMS on essential tremor showed an acute antitremor effect. Further investigation in search of a more lasting benefit is warranted.