Identifying comorbidities and lifestyle factors contributing to the cognitive profile of early Parkinson's disease.

BACKGROUND: Identifying modifiable risk factors for cognitive impairment in the early stages of Parkinson's disease (PD) and estimating their impact on cognitive status may help prevent dementia (PDD) and the design of cognitive trials. METHODS: Using a standard approach for the assessment of global cognition in PD and controlling for the effects of age, education and disease duration, we explored the associations between cognitive status, comorbidities, metabolic variables and lifestyle variables in 533 PD participants from the COPPADIS study. RESULTS: Among the overall sample, 21% of participants were classified as PD-MCI (n = 114) and 4% as PDD (n = 26). The prevalence of hypertension, diabetes and dyslipidemia was significantly higher in cognitively impaired patients while no between-group differences were found for smoking, alcohol intake or use of supplementary vitamins. Better cognitive scores were significantly associated with regular physical exercise (p < 0.05) and cognitive stimulation (< 0.01). Cognitive performance was negatively associated with interleukin 2 (Il2) (p < 0.05), Il6 (p < 0.05), iron (p < 0.05), and homocysteine (p < 0.005) levels, and positively associated with vitamin B12 levels (p < 0.005). CONCLUSIONS: We extend previous findings regarding the positive and negative influence of various comorbidities and lifestyle factors on cognitive status in early PD patients, and reinforce the need to identify and treat potentially modifiable variables with the intention of exploring the possible improvement of the global cognitive status of patients with PD.

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.