[Show abstract][Hide abstract] ABSTRACT: Semantic dementia patients seem to have better knowledge of information linked to the self. More specifically, despite having severe semantic impairment, these patients show that they have more general information about the people they know personally by direct experience than they do about other individuals they know indirectly. However, the role of direct personal experience remains debated because of confounding factors such as frequency, recency of exposure, and affective relevance. We performed an exploratory study comparing the performance of 5 semantic dementia patients with that of 10 matched healthy controls on the recognition (familiarity judgment) and identification (biographic information recall) of personally familiar names
versus famous names. As expected, intergroup comparisons indicated a semantic breakdown in semantic dementia patients as compared with healthy controls. Moreover, unlike healthy controls, the semantic dementia patients recognized and identified personally familiar names better than they did famous names. This pattern of results suggests that direct personal experience indeed plays a specific role in the relative preservation of person-specific semantic meaning in semantic dementia. We discuss the role of direct personal experience on the preservation of semantic knowledge and the potential neurophysiological mechanisms underlying these processes.
Full-text · Article · Nov 2015 · Frontiers in Human Neuroscience
[Show abstract][Hide abstract] ABSTRACT: Subjective emotional experience is thought to rely on a large cortical-subcortical network including orbitofrontal and cingulate frontostriatal circuits together with the mesolimbic dopaminergic system that modulates their activity. Parkinson's disease (PD) provides a model for exploring this issue. By using an original emotion induction procedure, the present study examined to what extent subjective experience of emotion of PD patients at different stages of the disease was modulated by emotion in the same way as healthy individuals. A battery of film excerpts was used to elicit different emotional feelings (happiness, anger, fear, sadness, disgust, and neutral) in 15 newly diagnosed PD patients, 18 patients with advanced PD and 15 matched controls. The newly diagnosed patients were examined in two conditions: "on" and "off" dopaminergic medication. Participants reported the intensity of their emotional feelings on a scale consisting of 10 emotional categories. Results indicated that PD patients at different stages of the disease did not significantly differ from the controls in the self-reported emotional experience to the presented film excerpts. Moreover, analyses conducted within the newly diagnosed PD group (on-dopa vs. off-dopa conditions) indicated that the patients' emotional reactivity to the presented film excerpts was not significantly modulated by dopaminergic medication. These results thus question the possible role of dopaminergic pathways in subjective emotional experience, at least in this sample and in the context of emotion induction.
Full-text · Article · Jul 2011 · Journal of the neurological sciences
[Show abstract][Hide abstract] ABSTRACT: Bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) can produce emotional disorders that have been linked to disturbance of the STN's limbic territory. The aim of this study was to confirm the impairment of the recognition of facial emotions (RFE) induced by STN DBS, not only ruling out the effect of the disease's natural progression in relation to the effect of DBS, but also assessing the influence of modifications in dopamine replacement therapy (DRT) following STN DBS. RFE was investigated in 24 PD patients who underwent STN DBS and 20 PD patients treated with apomorphine. They were assessed 3 months before and after treatment. The 2 patient groups were compared with a group of 30 healthy matched controls. The results showed that RFE for negative emotions (fear and sadness) was impaired in only the STN DBS group in the posttreatment condition and was unrelated to DRT. Results confirm the selective reduction of RFE induced by STN DBS, due neither to the disease's natural progression nor to modifications in DRT.
[Show abstract][Hide abstract] ABSTRACT: A number of studies have reported impaired facial emotion recognition following subthalamic nucleus (STN) stimulation in Parkinson's disease (PD), and have related these changes to a limbic dysfunction induced by STN stimulation. The present study examined the effect of STN stimulation in PD patients on a specific component of emotion, namely the subjective experience of emotion. Thirteen post-operative PD patients, 13 pre-operative PD patients matched on clinical and neuropsychological characteristics, and 16 controls matched on age and education, were administered a validated battery of film excerpts known to primarily induce specific emotional feelings (anger, happiness, sadness, fear, disgust, and neutral), and self-rated the intensity of their emotional feelings on a discrete emotions questionnaire. The post-operative group showed a significant lower level of differentiation between the target feeling (i.e., the more likely to be reported) and non-target feelings for the film excerpts intended to induce "sadness" and "fear" respectively, as compared with the pre-operative and healthy control groups. Moreover, the post-operative group reported significantly less intense feelings of fear, anxiety and disgust for the excerpt intended to induce "fear" as compared with the pre-operative and the control groups, while no significant difference was observed between the pre-operative and control groups. Finally, the post-operative group reported significantly less intense feelings of sadness and anxiety during the excerpt intended to induce "sadness" as compared to the control group, although the differences between the pre- and post-operative groups and between the pre-operative and the control groups did not reach significance. Our study suggests that STN stimulation affects the subjective experience of emotion, thus providing a preliminary account of the modulation induced by STN stimulation of a distributed neuronal network underlying the subjective experience of emotion, although the exact contribution of the STN within such network remains to be specified.
[Show abstract][Hide abstract] ABSTRACT: The "orbitofrontal" and "cingulate" frontostriatal loops and the mesolimbic dopaminergic system that modulates their function have been implicated in theory of mind (ToM). Parkinson's disease (PD) provides a model for assessing their role in humans. Results of the handful of previous studies of ToM in PD providing preliminary evidence of impairment remain controversial, mainly because the patients included in these studies were not accurately described, making it difficult to determine whether their ToM deficits were due to general cognitive deterioration or to a more specific dopaminergic deficit. The aim of our study was therefore to re-examine previous results highlighting ToM in PD and to explore the involvement of the dopaminergic pathways in ToM. ToM was investigated in 17 newly diagnosed PD patients (early PD group), 27 PD patients in the advanced stages of the disease (advanced PD group) and 26 healthy matched controls (HC), using two ToM tasks: a visual one, which is thought to reflect the "affective" ToM subcomponent ("Reading the Mind in the Eyes"), and a verbal one, which is thought to reflect both the "affective" and the "cognitive" ToM subcomponents (faux pas recognition). Furthermore, the early PD group was studied in two conditions: with and without dopamine replacement therapy (DRT). We failed to find any significant difference in ToM between the early PD patients and the HC group. Furthermore, there was no difference between the early PD patients in the medicated and unmedicated conditions. Conversely, the advanced PD patients scored poorly on the intention attribution question ("cognitive" ToM score) in the faux pas recognition task. The present results suggest that the deficit in ToM only occurs in the more advanced stages of the disease. In addition, our results would appear to indicate that these advanced PD patients present "cognitive" ToM impairment rather than global ("cognitive" and "affective") ToM impairment. In other words, the ToM deficit would appear to be present in PD patients where the degenerative process has spread beyond the dopaminergic pathways, but not in early PD patients where neuronal loss is thought to be restricted to the nigrostriatal and mesolimbic dopaminergic systems. In conclusion, our results suggest that the dopaminergic pathways are not involved in ToM.
[Show abstract][Hide abstract] ABSTRACT: 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 (18)FDG-PET. The (18)FDG-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.
[Show abstract][Hide abstract] ABSTRACT: To test the hypothesis that emotion recognition and apathy share the same functional circuit involving the subthalamic nucleus (STN).
A consecutive series of 17 patients with advanced Parkinson's disease (PD) was assessed 3 months 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 both M-3 and M3. Patients were 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.
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). There was 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 postoperative worsening of apathy and emotion recognition impairment were not correlated.
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 impairment suggests 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.
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
Full-text · Article · Sep 2006 · Journal of Neurology
[Show abstract][Hide abstract] ABSTRACT: Behavioural disturbances such as disorders of mood, apathy or indifference are often observed in Parkinson's disease (PD) patients with chronic high frequency deep brain stimulation of subthalamic nucleus (STN DBS). Neuropsychological modifications causing these adverse events induced by STN DBS remain unknown, even if limbic disturbances are hypothesised. The limbic system supports neural circuits processing emotional information. The aim of this work is to evaluate changes of emotional recognition in PD patients induced by STN DBS. Thirty PD patients were assessed using a computerised paradigm of recognition of emotional facial expressions [Ekman, P., & Friesen, W. V. (1976). Pictures of facial affect. Palo Alto, CA: Consulting Psychologists Press], 15 before STN DBS and 15 after. The two patients groups were compared to a group of 15 healthy control subjects. One series of 55 pictures of emotional facial expressions was presented to each patient. Patients had to classify the pictures according to seven basic emotions (happiness, sadness, fear, surprise, disgust, anger and no emotion). The intact ability to percept faces was firstly assured using the Benton Recognition Test. Recognition of fear expressions was significantly and selectively reduced in the post-operative group in comparison to both pre-operative and control groups. Our results demonstrate for the first time a selective reduction of recognition of facial expressions of fear by STN DBS. This impairment could be the first neuropsychological marker of a more general limbic dysfunction, thought to be responsible for the behavioural disorders reported after STN DBS.
No preview · Article · Feb 2005 · Neuropsychologia