Subthalamic nucleus stimulation affects orbitofrontal cortex in facial emotion recognition: a pet study

Deep brain stimulation (DBS) of the bilateral subthalamic nucleus (STN) in Parkinson's disease is thought to produce adverse events such as emotional disorders, and in a recent study, we found fear recognition to be impaired as a result. These changes have been attributed to disturbance of the STN's limbic territory and would appear to confirm that the negative emotion recognition network passes through the STN. In addition, it is now widely acknowledged that damage to the orbitofrontal cortex (OFC), especially the right side, can result in impaired recognition of facial emotions (RFE). In this context, we hypothesized that this reduced recognition of fear is correlated with modifications in the cerebral glucose metabolism of the right OFC. The objective of the present study was first, to reinforce our previous results by demonstrating reduced fear recognition in our Parkinson's disease patient group following STN DBS and, second, to correlate these emotional performances with glucose metabolism using 18FDG-PET. The 18FDG-PET and RFE tasks were both performed by a cohort of 13 Parkinson's disease patients 3 months before and 3 months after surgery for STN DBS. As predicted, we observed a significant reduction in fear recognition following surgery and obtained a positive correlation between these neuropsychological results and changes in glucose metabolism, especially in the right OFC. These results confirm the role of the STN as a key basal ganglia structure in limbic circuits

Does subthalamic nucleus stimulation induce apathy in Parkinson’s disease?

Background Subthalamic Nucleus Deep Brain Stimulation (STN-DBS) has been shown to significantly improve motor symptoms in advanced Parkinson’s disease (PD). Only few studies, however, have focused on the non-motor effects of DBS. Methods A consecutive series of 15 patients was assessed three months before (M-3), then three months (M3) and six months (M6) after surgery. Mean (± SD) age at surgery was 59.7 (7.6). Mean disease duration at surgery was 12.2 (2.8) years. The Mini International Neuropsychiatric Inventory was used to assess psychiatric disorders three months before surgery. Depression was evaluated using Montgomery and Asberg Rating Scale (MADRS). Anxiety was evaluated using the AMDP system (Association for Methodology and Documentation in Psychiatry). Apathy was particularly evaluated using the Apathy Evaluation Scale (AES) and the Starkstein Scale. All these scales were performed at every evaluation. Results Apathy worsened at M3 and M6 after STN-DBS in comparison with the preoperative evaluation: the AES mean score was significantly impaired between the preoperative (38.4±7.1) and both the postoperative M3 (44.6±9.5, p = 0.003) and M6 scores (46.0±10.9, p = 0.013). Significant worsening of apathy was confirmed using the Starkstein scale. There was no evidence of depression: the mean MADRS score did not differ before surgery (9.1±7.4) and at both M3 (8.6±8.2) and M6 (9.9±7.7) after STN-DBS. The anxiety level did not change between preoperative (9.4±9.2) and both M3 (5.5±4.5) and M6 (6.6±4.6) postoperative states. Conclusion Although STN-DBS constitutes a therapeutic advance for severely disabled patients with Parkinson’s disease, we should keep in mind that this surgical procedure may contribute to the inducing of apathy. Our observation raises the issue of the direct influence of STN- DBS on the limbic system by diffusion of stimulus to the medial limbic compartment of STN

Emotion recognition impairment and apathy after subthalamic nucleus stimulation in Parkinson's disease have separate neural substrates

Objective: To test the hypothesis that emotion recognition and apathy share the same functional circuit involving the subthalamic nucleus (STN). Methods:Aconsecutive series of 17 patients with advancedParkinson’s disease (PD)was assessed3months before (M−3) and 3 months (M+ 3) after STN deep brain stimulation (DBS). Mean (±S.D.) age at surgery was 56.9 (8.7) years. Mean disease duration at surgery was 11.8 (2.6) years. Apathy was measured using the Apathy Evaluation Scale (AES) at bothM−3 and M3. Patientswere also assessed using a computerised paradigm of facial emotion recognition [Ekman, P., & Friesen, W. V. (1976). Pictures of facial affect. Palo Alto: Consulting Psychologist Press] before and after STN DBS. Prior to this, the Benton Facial Recognition Test was used to check that the ability to perceive faces was intact. Results: Apathy had significantly worsened at M3 (42.5±8.9, p = 0.006) after STN-DBS, in relation to the preoperative assessment (37.2±5.5). Therewas also a significant reduction in recognition percentages for facial expressions of fear (43.1%±22.9 vs. 61.6%±21.4, p = 0.022) and sadness (52.7%±19.1 vs. 67.6%±22.8, p = 0.031) after STN DBS. However, the postoperativeworsening of apathy andemotion recognition impairment were not correlated. Conclusions: Our results confirm that the STN is involved in both the apathy and emotion recognition networks. However, the absence of any correlation between apathy and emotion recognition impairmentsuggests that the worsening of apathy following surgery could not be explained by a lack of facial emotion recognition and that its behavioural and cognitive components should therefore also be taken into consideration

Correlating Clinical Scores with Anatomical Electrodes Locations for Assessing Deep Brain Stimulation

International audienceMovement disorders in patients with Parkinson's disease may require functional surgery, when medical therapy isn't effective. In Deep Brain Stimulation (DBS), electrodes are implanted within the brain to stimulate deep structures such as SubThalamic Nucleus (STN). This paper describes successive steps for constructing digital atlases gathering patient's location of electrode contacts and clinical scores. Three motor and three neuro- psychological scores were integrated in the study. Correlations between active contacts localization and clinical data were carried out using an adapted Hierarchical Ascendant Classification and have enabled the extraction of clusters aiming to suggest optimum sites for therapeutic STN DBS. The postero-superior region has been found to be effective for motor score improvement whereas the antero-inferior region revealed noticeable neuro- psychological scores deterioration. Comparison with existing results has shown that such atlases are very promising for understanding phenomena better

Emotion Recognition in Parkinson's disease after Subthalamic Deep Brain Stimulation: Differential effects of lesion and STN stimulation

Deep brain stimulation of the subthalamic nucleus (STN-DBS) has acquired a relevant role in the treatment of Parkinson\u2019s disease (PD). Despite being a safe procedure, it may expose patients to an increased risk to experience cognitive and emotional difficulties. Impair- ments in emotion recognition, mediated both by facial and prosodic expressions, have been reported in PD patients treated with such procedure. However, it is still unclear whether the STN per se is responsible for such changes or whether others factors like the microlesion produced by the electrode implantation may also play a role. In this study we evaluated facial emotions discrimination and emotions recognition using both facial and prosodic expressions in 12 patients with PD and 13 matched controls. Patients\u2019 were tested in four conditions: before surgery, both in on and off medication, and after surgery, respectively few days after STN implantation before turning stimulator on and few months after with stimulation on. We observed that PD patients were impaired in discriminating and recognizing facial emotions, especially disgust, even before DBS implant. Microlesion caused by surgical procedure was found to influence patients\u2019 performance on the discrimination task and recognition of sad facial expression while, after a few months of STN stimulation, impaired disgust recognition was again prominent. No impairment in emotional prosody recognition was observed both before and after surgery. Our study confirms that PD patients may experience a deficit in disgust recognition and provides insight into the differential effect of microlesion and stimulation of STN on several tasks assessing emotion recognition