Cognitive training in Parkinson's disease reduces cognitive decline in the long term.

BACKGROUND AND PURPOSE: Patients with Parkinson's disease (PD) are at high risk for cognitive dysfunction. Non-pharmacological interventions have attracted increasing interest for enhancing PD patients' cognitive functions. METHODS: One-year follow-up data (T2 ) of a randomized controlled trial evaluating two 6-week cognitive trainings - a structured (NEUROvitalis, NV) and an unstructured (mentally fit, MF) program - compared with a waiting list control group (CG) in non-demented PD patients (Hoehn and Yahr I-III) are presented. Forty-seven PD patients were examined at T2 . Effects on overall cognitive functions (Mini-Mental State Examination and DemTect) were compared between all groups with repeated measurement analyses of variance. A combined score of the percentage change value from baseline (T0 ) to T2 was calculated to identify patients who retained or improved their cognitive state (responders). The risk of developing mild cognitive impairment (MCI) was analyzed. RESULTS: Significant time × treatment effects on overall cognitive functions were found for both training groups, each compared separately to the CG (DemTect, P < 0.05). Nine patients (56.3%) of the NV group, seven (41.2%) of the MF group and three (21.4%) of the CG were responders. Comparing NV to CG the odds ratio was 4.7 [95% confidence interval (0.8; 33.3)], and comparing MF to CG it was 2.6 [95% confidence interval (0.4; 17.4)]. MCI risk for patients without prior MCI was 40.0% in CG, 18.2% in MF and 18.2% in NV. The odds ratio was 3 comparing NV to CG, MF to CG. DISCUSSION: This study gives evidence that cognitive training may be effective to prevent cognitive decline and onset of MCI in PD patients.

Pharmacological treatment of deep brain stimulation-induced hypomania leads to clinical remission while preserving motor benefits.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for Parkinson's disease, but can lead to adverse effects including psychiatric disturbance. Little is known about the risk factors and treatment options for such effects. Here, we describe a patient who reproducibly developed stimulation-induced hypomania when using ventrally located electrodes and responded well to pharmacological intervention while leaving the stimulation parameters unchanged to preserve motor benefits. In spite of clinical remission, [¹5O]-positron-emission-tomography (PET) demonstrated activation patterns similar to those reported during mania. This case, therefore, highlights an important treatment option of adverse effects of DBS, but also points toward the need for investigations of its risk factors and their underlying neurobiological mechanisms.

Effects of deep brain stimulation on prepulse inhibition in obsessive-compulsive disorder.

Owing to a high response rate, deep brain stimulation (DBS) of the ventral striatal area has been approved for treatment-refractory obsessive-compulsive disorder (tr-OCD). Many basic issues regarding DBS for tr-OCD are still not understood, in particular, the mechanisms of action and the origin of side effects. We measured prepulse inhibition (PPI) in treatment-refractory OCD patients undergoing DBS of the nucleus accumbens (NAcc) and matched controls. As PPI has been used in animal DBS studies, it is highly suitable for translational research. Eight patients receiving DBS, eight patients with pharmacological treatment and eight age-matched healthy controls participated in our study. PPI was measured twice in the DBS group: one session with the stimulator switched on and one session with the stimulator switched off. OCD patients in the pharmacologic group took part in a single session. Controls were tested twice, to ensure stability of data. Statistical analysis revealed significant differences between controls and (1) patients with pharmacological treatment and (2) OCD DBS patients when the stimulation was switched off. Switching the stimulator on led to an increase in PPI at a stimulus-onset asynchrony of 200 ms. There was no significant difference in PPI between OCD patients being stimulated and the control group. This study shows that NAcc-DBS leads to an increase in PPI in tr-OCD patients towards a level seen in healthy controls. Assuming that PPI impairments partially reflect the neurobiological substrates of OCD, our results show that DBS of the NAcc may improve sensorimotor gating via correction of dysfunctional neural substrates. Bearing in mind that PPI is based on a complex and multilayered network, our data confirm that DBS most likely takes effect via network modulation.