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Background: The aim of the present study was to assess the consequences of a simplification of the electrophysiological procedure on the post-operative clinical outcome after subthalamic nucleus implantation in Parkinson disease., Methods: Microelectrode recordings were performed on 5 parallel trajectories in group 1 and less than 5 trajectories in group 2. Clinical evaluations were performed 1 month before and 6 months after surgery., Results: After surgery, the UPDRS III score in the off-drug/on-stimulation and on-drug/on-stimulation conditions significantly improved by 66,9% and 82%, respectively in group 1, and by 65.8% and 82.3% in group 2 (P<0.05). Meanwhile, the total number of words (P<0.05) significantly decreased for fluency tasks in both groups. Motor disability improvement and medication reduction were similar in both groups., Conclusions: Our results suggest that the electrophysiological procedure should be simplified as the team's experience increases.

Background: Pre-operative predictive factors for optimal post-operative effect of subthalamic nucleus (STN) stimulation in Parkinson's disease (PD) have been previously reported. No study has explicitly assessed the link between excess pre-operative body weight and STN stimulation outcome., Methods: We retrospectively compared STN stimulation outcomes of 36 PD patients with excess pre-operative body weight (group 1) and 36 matched normal-weight pre-operative (group 2) PD patients. We focused on the post-operative outcomes in the sub-group of 12 obese (group 3) PD patients., Results: The post-operative motor improvement and the reduction of severity of levodopa-related complications were not statistically different between groups 1 and 2 (P>0.05). In the obese group (group 3), the axial sub-score significantly improved by 29.8% in the on-drug/on-stimulation conditions whereas the improvement was not significant in the off-drug/on-stimulation condition (22.4%, P=0.20). The post-operative Mattis Dementia Rating Score was significantly reduced in group 1 and group 3., Discussion: We considered that the post-operative axial impairment observed in the obese PD patients might be essentially consecutive to disease progression and/or post-operative DBS consequences, i.e. surgical procedure or electrical stimulation itself. Moreover, it could be argued that musculoskeletal disorders associated with obesity were responsible for the incomplete efficacy of STN stimulation on axial sub-scores, by increasing gait and balance impairment., Conclusion: Pre-operative obesity may be regarded as a predictive clinical factor of axial and cognitive impairment after STN-DBS., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Decline in verbal fluency (VF) is frequently reported after chronic deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson disease (PD)., Objective: We investigated whether the trajectory of the implanted electrode correlate with the VF decline 6 months after surgery., Methods: We retrospectively analysed 59 PD patients (mean age, 61.9 ± 7; mean disease duration, 13 ± 4.6) who underwent bilateral STN-DBS. The percentage of VF decline 6 months after STN-DBS in the on-drug/on-stimulation condition was determined in respect of the preoperative on-drug condition. The patients were categorised into two groups (decline and stable) for each VF. Cortical entry angles, intersection with deep grey nuclei (caudate, thalamic or pallidum), and anatomical extent of the STN affected by the electrode pathway, were compared between groups., Results: A significant decline of both semantic and phonemic VF was found after surgery, respectively 14.9% ± 22.1 (P < 0.05) and 14.2% ± 30.3 (P < 0.05). Patients who declined in semantic VF (n = 44) had a left trajectory with a more anterior cortical entry point (56 ± 53 versus 60 ± 55 degree, P = 0.01) passing less frequently trough the thalamus (P = 0.03)., Conclusions: Microlesion of left brain regions may contribute to subtle cognitive impairment following STN-DBS in PD.

Backgrounds: An early and transient verbal fluency (VF) decline and impairment in frontal executive function, suggesting a cognitive microlesion effect may influence the cognitive repercussions related to subthalamic nucleus deep brain stimulation (STN-DBS)., Methods: Neuropsychological tests including semantic and phonemic verbal fluency were administered both before surgery (baseline), the third day after surgery (T3), at six months (T180), and at an endpoint multiple years after surgery (Tyears)., Results: Twenty-four patients (mean age, 63.5 ± 9.5 years; mean disease duration, 12 ± 5.8 years) were included. Both semantic and phonemic VF decreased significantly in the acute post-operative period (44.4 ± 28.2% and 34.3 ± 33.4%, respectively) and remained low at 6 months compared to pre-operative levels (decrease of 3.4 ± 47.8% and 10.8 ± 32.1%) (P < 0.05). Regression analysis showed phonemic VF to be an independent factor of decreased phonemic VF at six months. Age was the only independent predictive factor for incident Parkinson's disease dementia (PDD) (F (4,19)=3.4, P<0.03)., Conclusion: An acute post-operative decline in phonemic VF can be predictive of a long-term phonemic VF deficit. The severity of this cognitive lesion effect does not predict the development of dementia which appears to be disease-related., (Copyright © 2014 Elsevier B.V. All rights reserved.)