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The subthalamic nucleus (STN) is the main target for deep brain stimulation in Parkinson's disease. We analysed the relationships between magnetic resonance imaging (MRI) anatomy and spontaneous neuronal activity to confirm the potential of microelectrode recordings to assist in determining the optimal surgical target. Ten bilateral surgeries were performed after 1.5-T (T2-weighted) anatomical MRI identification of the STN, zona incerta (ZI), Forel's field H2 (H2) and substantia nigra (SN). Spontaneous neuronal activity was recorded simultaneously along the distal 10 mm on a central track (optimally covering the STN) and a 2-mm anterior track. We calculated off-line mean firing rate and burst frequency on 248 neurons clustered according to anatomical structure. Subjective visual analysis of signal was also realized on-line, during surgery, to classify patterns of activity. Mean firing rate and burst frequency increased from H2-ZI to SN. The mean firing rate was higher in SN only using paired comparison (SN vs. its neighbours). The burst frequency was lower in H2 than in SN; using comparison with neighbours, it was lower in H2 and ZI. An irregular high activity (type 2C) was more often detected in STN and SN than in H2 and ZI. Anatomical boundaries and unitary recordings appear to be linked, supporting the ability of MRI to provide a detailed anatomy. Electrophysiological mapping combined with MRI is a useful tool for precise targeting in the subthalamic region.

Subthalamic nucleus (STN) targeting is classically performed based on AC-PC probabilistic position. Nevertheless, MRI allows direct visualization and targeting. We aimed to compare the position localized on MR images with standard stereotactic diagrams. The STN was manually contoured on MR images (22 Parkinson's disease patients); boundaries were simplified in a schematic polygonal form. Front and lateral stereotactic diagrams were constructed according to Talairach and Benabid. We compared x, y and z coordinates of the geometrical center of MRI-based polygons and stereotactic diagrams (Wilcoxon matched-pairs tests). There was significant discordance between MRI-based polygons and AC-PC-based images. MRI shows the STN as more posterior, medial and slightly inferior., ((c) 2009 S. Karger AG, Basel.)

Objective: To assess the role of age in the results of bilateral deep brain stimulation in the subthalamic nucleus (DBS-STN), we carried out a study of two groups of patients regarding age at time of surgery., Methods: We compared, up to 2 years after surgery, the clinical effects, safety, and quality of life in parkinsonian patients younger than 65 years old (young patients) vs parkinsonian patients 65 years old or older (old patients)., Results: The mean age was 57.4 +/- 4.9 years (n = 53) in young patients and 68.8 +/- 2.8 years (n = 34) in old patients. A dramatic improvement in motor complications was equally observed in both groups of patients. There was no significant difference between the groups regarding acute effects of DBS-STN on the motor score of the Unified Parkinson's Disease Rating Scale part III (UPDRS III). Time course evolution of UPDRS the motor score (p < 0.0001) and axial score (p = 0.0001) assessed postoperatively in "on" medication and "on" stimulation conditions appeared worse in old patients as compared to young patients. Improvement in the Schwab and England Scale score was better in young patients in "on" (p < 0.0003) and "off" state (p < 0.001). Quality of life assessed with the 39-item Parkinson's Disease Questionnaire showed an improvement in subscales evaluating mobility (p < 0.0001), activities of daily life (p < 0.0001), emotion and stigma (p = 0.0004), cognition (p < 0.0074), and communication (p = 0.0029) in young patients as compared to old patients. Side effects were similar in the two groups., Conclusions: Although deep brain stimulation in the subthalamic nucleus reduces motor complications equally in both groups of patients, postoperative quality of life improved only in young patients.