Wait and you shall see: sexual delay discounting in hypersexual Parkinson's disease.

Patients with Parkinson's disease may develop impulse control disorders under dopaminergic treatments. Impulse control disorders include a wide spectrum of behaviours, such as hypersexuality, pathological gambling or compulsive shopping. Yet, the neural systems engaged in specific impulse control disorders remain poorly characterized. Here, using model-based functional MRI, we aimed to determine the brain systems involved during delay-discounting of erotic rewards in hypersexual patients with Parkinson's disease (PD+HS), patients with Parkinson's disease without hypersexuality (PD - HS) and controls. Patients with Parkinson's disease were evaluated ON and OFF levodopa (counterbalanced). Participants had to decide between two options: (i) wait for 1.5 s to briefly view an erotic image; or (ii) wait longer to see the erotic image for a longer period of time. At the time of decision-making, we investigated which brain regions were engaged with the subjective valuation of the delayed erotic reward. At the time of the rewarded outcome, we searched for the brain regions responding more robustly after waiting longer to view the erotic image. PD+HS patients showed reduced discounting of erotic delayed rewards, compared to both patients with Parkinson's disease and controls, suggesting that they accepted waiting longer to view erotic images for a longer period of time. Thus, when using erotic stimuli that motivate PD+HS, these patients were less impulsive for the immediate reward. At the brain system level, this effect was paralleled by the fact that PD+HS, as compared to controls and PD - HS, showed a negative correlation between subjective value of the delayed reward and activity of medial prefrontal cortex and ventral striatum. Consistent with the incentive salience hypothesis combining learned cue-reward associations with current relevant physiological state, dopaminergic treatment in PD+HS boosted excessive 'wanting' of rewards and heightened activity in the anterior medial prefrontal cortex and the posterior cingulate cortex, as reflected by higher correlation with subjective value of the option associated to the delayed reward when ON medication as compared to the OFF medication state. At the time of outcome, the anterior medial prefrontal/rostral anterior cingulate cortex showed an interaction between group (PD+HS versus PD - HS) and medication (ON versus OFF), suggesting that dopaminergic treatment boosted activity of this brain region in PD+HS when viewing erotic images after waiting for longer periods of time. Our findings point to reduced delay discounting of erotic rewards in PD+HS, both at the behavioural and brain system levels, and abnormal reinforcing effect of levodopa when PD+HS patients are confronted with erotic stimuli.10.1093/brain/awy298_video1awy298media15983845074001.

Intravenous immunoglobulin and rituximab for cerebellar ataxia with glutamic acid decarboxylase autoantibodies.

Cerebellar ataxia associated with glutamic acid decarboxylase autoantibodies (GAD-ab) is a rare and usually slow progressive disease with moderate to severe gait and limb ataxia, dysarthria, and nystagmus. The treatment for this condition is still being discussed. We report the cases of three patients with GAD-ab cerebellar ataxia treated successively with intravenous immunoglobulin (IVIg) and rituximab. Symptoms improved in one case after rituximab therapy and were stabilized in another after a combined therapy of IVIg and rituximab. The third patient continued to worsen despite these treatments. We conclude that IVIg and rituximab therapy could improve or stabilize GAD-ab cerebellar ataxia. Early treatment, the lack of cerebellar atrophy on magnetic resonance imaging, and a subacute onset of the symptoms could be decisive prognostic factors.

Prevalence and phenomenology of olfactory hallucinations in Parkinson's disease.

BACKGROUND: Although visual hallucinations in Parkinson's disease (PD) have been described in several major studies, little is known about olfactory hallucinations (OHs). METHODS: The authors performed a detailed analysis of OHs in a cohort of 87 Parkinsonian patients to estimate the prevalence of OHs and describe their phenomenology. They also evaluated smelling abilities in terms of detection and identification. Assessment of both, OHs and olfactory function, was also performed using a control group of 40 normal subjects. RESULTS: Nine patients exhibited OHs compared with none of the controls, giving a prevalence of 10% for OHs in patients. OHs were described as rare, short-lasting, unpleasant odours which are not frightening since clearly identified by the patient as hallucinations. Parkinsonian patients with OHs exhibited olfactory impairment of detection and identification compared with controls, but there was no difference in their olfactory abilities from Parkinsonian patients without OHs. CONCLUSIONS: In conclusion, OHs should be added to the list of non-motor PD symptoms that can occur early or late in the course of PD. The authors' study did not reveal any significant difference in terms of olfactory abilities between patients with or without OHs. However, olfactory impairment is well documented in Parkinsonian patients and cannot be totally ruled out as a risk factor for OHs. The authors recognise that complex mechanisms are probably involved in this phenomenon.

Carotid web: the challenging diagnosis of an under-recognized entity.

BACKGROUND: Determining the cause of acute ischemic stroke is crucial for patient management, particularly for preventing future stroke. In recent years, carotid web (CW), a non-atherosclerotic disorder of the carotid wall, has been found to be an underestimated source of cerebral emboli. OBJECTIVE: The present study aimed to analyze the clinical, radiological, and pathological findings, along with the treatments performed in patients with CW and ipsilateral ischemic events. METHODS: Patients with anterior circulation ischemic stroke or transient ischemic attack and ipsilateral CW were prospectively included from January 2019 to December 2021. RESULTS: Nine patients were enrolled. The median age was 55 (43-62) years, with a female-to-male ratio of 3.5:1. Of the total, seven patients (78%) consulted for recurrent ipsilateral ischemic events. Despite medical treatment, 44% of the patients experienced new episodes. Computed tomographic angiography was suggestive of CW in all cases in which it was performed. The interval between the first ischemic event and diagnosis of CW was of 13 (6-68) months. After ruling out any other possible etiology, every patient underwent carotid revascularization, one underwent stenting and eight underwent carotidectomy. No severe or long-term complications were noted. Histological studies confirmed the diagnosis of CW. There were no recurrences after carotid revascularization during a follow-up of 24 (13-35) months. CONCLUSION: Knowledge of CW and differentiating it from atheroma plaques is essential, as medical management seems to be insufficient in many cases. Revascularization, which has been shown to be safe and effective, might be the best treatment modality.

Contact dependent reproducible hypomania induced by deep brain stimulation in Parkinson's disease: clinical, anatomical and functional imaging study.

Hypomanic symptoms depending on anatomical location of contacts are reported in patients with Parkinson's disease (PD) treated by deep brain stimulation (DBS) of the subthalamic nucleus (STN). However, the underlying cortical and subcortical dysfunction is debated. In this study, five PD patients implanted with DBS-STN who presented with reversible and reproducible hypomanic symptoms after stimulation of specific 'manic' contacts were investigated. Hypomanic symptoms were assessed using the Bech and Rafaelsen Mania Scale (MAS). Three dimensional anatomical location of 'euthymic' and 'manic' contacts, after matching the postoperative CT scan with the preoperative stereotactic MRI, and a H(2)(15)O positron emission tomography (PET) study testing 'euthymic' and 'manic' contacts, were performed. Under 'euthymic' conditions, MAS score (mean±SD) was 0.6±0.5 compared with 7.8±3.1 under 'manic' conditions. Nine of 10 'manic' contacts were located in the substantia nigra, mainly in its ventral part. PET showed that hypomania was associated with strong asymmetrical cerebral activation involving preferentially the right hemisphere and was mediated by activation of the anterior cingulate and medial prefrontal cortex. The present study demonstrates the role of the subcortical structures in the genesis of hypomania in PD patients treated with DBS and stresses the involvement of the substantia nigra.

Hypersexuality and pathological gambling in Parkinson's disease: A cross-sectional case-control study.

BACKGROUND: Substance and behavioral addictions have already been described separately or in combination in Parkinson's disease. However, no comparisons of the prevalence of addictive behaviors in patients with Parkinson's disease and the general population have been published. The objective of this study was to compare the prevalence and characteristics of addictions (gambling, hypersexuality, tobacco, and alcohol) in patients with Parkinson's disease and in a matched, paired sample from the general population. METHODS: After matching for age, sex, and complete field questionnaires on addictions, we had 115 data sets. RESULTS: No difference was observed between Parkinson's disease and control populations concerning pathological gambling (0.87% vs 0.87%, P = .99), tobacco addiction (1.7% vs 1.7%, P = .99), and alcohol dependence (2.6% vs 3.5%, P = .71). The Parkinson's disease group showed 2 cases of sexual addiction (1.7% vs 0, P = .15). CONCLUSIONS: Our results indicate that patients with Parkinson's disease do not have specific profiles for tobacco or alcohol addiction and pathological gambling compared with the general population.

Subthalamic nucleus location: relationships between stereotactic AC-PC-based diagrams and MRI anatomy-based contours.

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.

Oblique multiplanar reformation in multislice temporal bone CT.

We made an anatomic study using a convenience sample of 20 patients, most of them referred to our institution for depicting internal auditory malformations that justify sensorineural deafness or for surgical planning of cochlear implants. All patients underwent a multislice temporal bone CT and oblique single slice reformation postprocessing in six proposed different planes corresponding to cochlear basal turn, apical basal turn, malleoincudal complex, stapes, and facial channel. Anatomic and pathologic characterization of some middle and inner ear structures, difficult to evaluate in standard axial and coronal planes, can be improved using this technique.

Treatment of Intracranial Aneurysms With the SILK Embolization Device in a Multicenter Study. A Retrospective Data Analysis.

BACKGROUND: Flow-diverter technology has become an important stent-based embolization tool in the treatment of complex cerebrovascular pathology. We report here the experience of 4 Spanish centers with using the SILK flow-diverter (SFD) device. OBJECTIVE: To evaluate the safety and efficacy of using the SFD in the endovascular treatment of intracranial aneurysms with complex morphology. METHODS: We retrospectively examined a prospectively maintained database of patients treated with SFD devices between July 2008 and December 2013 at 1 of 4 institutions in Spain. Data regarding patient demographics, aneurysm characteristics, and technical procedure were analyzed. Angiographic and clinical findings were recorded during the procedure and at 12 months postoperatively. RESULTS: A total of 175 SFD devices were implanted in 157 patients (women/men: 119/38; mean, median, and range of age: 56.2, 56.7, and 19-80 years, respectively), who were treated in a delayed manner (3-6 months from the event) for 180 aneurysms (165 unruptured and 15 ruptured). Adverse events (acute and delayed) were observed in 28.7% of cases (45/157), and most were resolved (19.1%; 30/157). Six months after the procedure, total morbidity and mortality were 9.6% (15/157) and 3.2% (5/157), respectively. Long-term imaging follow-up showed complete occlusion, neck remnants, and residual aneurysm in 78.1% (100/128), 14.0% (18/128), and 7.8% (10/128) of cases, respectively. CONCLUSIONS: The SFD device is an effective tool for the treatment of challenging aneurysms, and allows complete occlusion within a year of the procedure in most patients, with morbidity and mortality comparable to those previously reported for similar devices.

Subthalamus stimulation in Parkinson disease: Accounting for the bilaterality of contacts.

BACKGROUND: Deep brain stimulation (DBS) in Parkinson's disease uses bi-hemispheric high-frequency stimulation within the subthalamus, however, the specific impacts of bilaterality of DBS are still not clear. Thus, we aimed to study the individual-level clinical impact of locations of right-left contact pair-up accounting for each subthalamic nucleus (STN) anatomy. METHODS: Contact locations and effects at 1 year were studied retrospectively in an unselected series of 53 patients operated between 2004 and 2010. Location of contacts was defined relatively to the main axis of STN used to map longitudinal and transversal positions, and STN membership (out meaning out-of-STN). Contact pairings were described via three methods: (i) Unified contact location (UCL) collapsing DBS into an all-in-one contact; (ii) balance of contact pair-up (BCPU), defined as symmetric or asymmetric regardless of laterality; (iii) hemisphere-wise most frequent contact pair-up (MFCP) regardless of BCPU. Clinical data were: mean levodopa equivalent dose, Unified Parkinson's Disease Rating Scale (UPDRS) motor score III without medication, UPDRS II and III speech sub-scores, UPDRS II freezing sub-score, 1 year versus preoperative values, with and without levodopa. Ad-hoc two-sided tests were used for statistical analysis. RESULTS: Worsening speech, was more frequent for UCL_out patients and when the left MFCP contact was rear and/or superolateral, however, it less frequent for BCPU-asymmetric patients. Worsening freezing was more frequent when the right MFCP contact was rear and superolateral. CONCLUSIONS: These results point to strategies for minimizing dysarthria and freezing as adverse effects of DBS.

Impact of Mood and Behavioral Disorders on Quality of Life in Parkinson's disease.

BACKGROUND: Mood symptoms negatively affect quality of life of Parkinson's disease (PD); however little is known about the impact of behavioral disorders such as impulse control disorders, and non-motor fluctuations on quality of life. OBJECTIVE: To assess the impact of mood and behavioral disorders on quality of life in PD. METHODS: 136 (84% male) PD were included (mean age: 61 ± 8y; mean duration of disease: 8.8 ± 5.4y). Mood symptoms, behavioral disorders and non-motor fluctuations were detected and quantified using the recently validated "Ardouin Scale of Behavior in Parkinson's Disease". Motor symptoms were assessed using UPDRS and quality of life with the "39-item Parkinson's Disease Questionnaire". RESULTS: Both motor and non-motor factors significantly affected the quality of life of PD patients. Multivariate regression of the relationship between items of the quality of life questionnaire and the Ardouin Scale showed that alteration of patients' quality of life was strongly correlated with the presence of mood symptoms (such as depression, anxiety ...) and with non-motor fluctuations (especially in the OFF period). A significant correlation was also found between the number of symptoms and their severity, and the quality of life deterioration. Some behavioral disorders (compulsive buying / eating behavior) also negatively affected patient's quality of life to a lesser extent. Alternatively, excess in motivation and hobbyism behaviors had a positive impact on mobility and emotional well-being dimensions respectively of quality of life. CONCLUSIONS: This study shows the main impact of mood symptoms and non-motor fluctuations on worsening quality of life in PD.

Long-term efficacy and tolerability of bilateral pallidal stimulation to treat tardive dyskinesia.

OBJECTIVE: To confirm the efficacy and safety of deep brain stimulation (DBS) of the internal part of the globus pallidus in improving severe tardive dyskinesia (TD). METHODS: Nineteen patients with severe pharmacoresistant TD were included. All were assessed at baseline and at 3, 6 (main outcome measure), and 12 months, and in the long term (6-11 years) for 14 patients, after bilateral pallidal DBS, using motor scales (Extrapyramidal Symptoms Rating Scale [ESRS], Abnormal Involuntary Movement Scale [AIMS]), cognitive scales, and a psychiatric assessment. At 6 months, a double-blind ESRS evaluation was performed in the stimulation "on" and stimulation "off" conditions. RESULTS: At 6 months, all patients had a decrease of more than 40% on the ESRS. The efficacy of the procedure was confirmed by a double-blind evaluation. This improvement was maintained at 12 months (ESRS: decrease of 58% [21%-81%]; AIMS: decrease of 50% [7%-77%]) and in the long term (ESRS: decrease of 60% [22%-90%]; AIMS: decrease of 63% [14%-94%], n = 14). All the subscores of the ESRS (parkinsonism, dystonia, and chorea) and of the AIMS (facial, oral, extremities, and trunk movements) improved. Despite psychiatric comorbidities at baseline, cognitive and psychiatric tolerability of the procedure was excellent. No cognitive decline was observed and mood was improved in most of the patients. CONCLUSIONS: Pallidal DBS procedure should be considered as a therapeutic option in disabling TD refractory to medical treatment. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that in patients with severe pharmacoresistant TD with implanted pallidal leads, the stimulation "on" condition significantly improved ESRS scores compared to the stimulation "off" condition.

Emergence of restless legs syndrome after subthalamic stimulation in Parkinson's disease: a dopaminergic overstimulation?

OBJECTIVE: Studies investigating the effects of subthalamic deep-brain stimulation (DBS-STN) on restless legs syndrome (RLS) in Parkinson's disease (PD) are limited and report conflicting results, with some describing the emergence of RLS after DBS-STN, while others report postoperative improvement of this disorder. Severe decrease in postoperative dopaminergic medications dose, which may unmask RLS symptoms, has been proposed to explain the emergence of RLS after surgery. We aimed to specifically identify factors associated with the risk of developing RLS after DBS-STN in order to enhance our comprehension of the underlying mechanisms contributing to the development of RLS in PD. PATIENTS: In this observational prospective study, we evaluated the occurrence of RLS in 31 patients with PD originally free from RLS symptoms, six months after bilateral chronic DBS-STN, and compared clinical and treatment parameters of patients who developed postoperative RLS with those of patients without postoperative RLS. RESULTS: Six patients out of 31 reported post-operative emergence of RLS. There was no between-group difference in demographic data, pre-operative treatment parameters or clinical improvement measures after DBS-STN. However, PD patients with emergence of RLS after DBS-STN had a higher dose of dopamine agonists at postoperative evaluation compared to PD patients without emergence of RLS (p = 0.040) and a lower percentage of decrease in dopamine agonists (p = 0.043). CONCLUSION: Overstimulation resulting from cumulative effects of dopamine agonists and STN-DBS may induce changes in excitability of the dopaminergic system, leading to an emergence of RLS. Clinicians should take into account this phenomenon while adjusting pharmacological treatment after surgery.

Network structure of brain atrophy in de novo Parkinson's disease.

We mapped the distribution of atrophy in Parkinson's disease (PD) using magnetic resonance imaging (MRI) and clinical data from 232 PD patients and 117 controls from the Parkinson's Progression Markers Initiative. Deformation-based morphometry and independent component analysis identified PD-specific atrophy in the midbrain, basal ganglia, basal forebrain, medial temporal lobe, and discrete cortical regions. The degree of atrophy reflected clinical measures of disease severity. The spatial pattern of atrophy demonstrated overlap with intrinsic networks present in healthy brain, as derived from functional MRI. Moreover, the degree of atrophy in each brain region reflected its functional and anatomical proximity to a presumed disease epicenter in the substantia nigra, compatible with a trans-neuronal spread of the disease. These results support a network-spread mechanism in PD. Finally, the atrophy pattern in PD was also seen in healthy aging, where it also correlated with the loss of striatal dopaminergic innervation.

Is R2* a new MRI biomarker for the progression of Parkinson's disease? A longitudinal follow-up.

PURPOSE: To study changes of iron content in basal ganglia in Parkinson's disease (PD) through a three-year longitudinal follow-up of the effective transverse relaxation rate R2*, a validated MRI marker of brain iron content which can be rapidly measured under clinical conditions. METHODS: Twenty-seven PD patients and 26 controls were investigated by a first MRI (t0). Longitudinal analysis was conducted among the 18 controls and 14 PD patients who underwent a second MRI (t1) 3 years after. The imaging protocol consisted in 6 gradient echo images obtained at different echo-times for mapping R2*. Quantitative exploration of basal ganglia was performed by measuring the variation of R2* [R2*(t1) - R2*(t0)] in several regions of interest. RESULTS: During the three-year evolution of PD, R2* increased in Substantia nigra (SN) (by 10.2% in pars compacta, p = 0.001, and 8.1% in pars reticulata, p = 0.013) and in the caudal putamen (11.4%, p = 0.011), without significant change in controls. Furthermore, we showed a positive correlation between the variation of R2* and the worsening of motor symptoms of PD (p = 0.028). CONCLUSION: Significant variation of R2* was longitudinally observed in the SN and caudal putamen of patients with PD evolving over a three-year period, emphasizing its interest as a biomarker of disease progression. Our results suggest that R2* MRI follow-up could be an interesting tool for individual assessment of neurodegeneration due to PD, and also be useful for testing the efficiency of disease-modifying treatments.

Central pain modulation after subthalamic nucleus stimulation: A crossover randomized trial.

OBJECTIVE: To investigate the acute effect of subthalamic nuclei deep brain stimulation (STN-DBS) and levodopa on pain and tolerance thresholds in patients with Parkinson disease. We hypothesized that a modification of pain threshold after STN-DBS would suggest a central modification of pain perception, whereas the absence of pain threshold change after STN-DBS would correspond to a peripheral mechanism via a decrease of painful stimuli. METHODS: Nineteen patients with Parkinson disease were included in this double-blind, randomized, crossover study. Postoperatively, we evaluated pain thresholds (thermal and mechanical) and motor symptoms under 3 acute conditions: stimulation on/medication off; stimulation off/medication on; and stimulation off/medication off. We also conducted a retrospective analysis of the data prospectively recorded during the follow-up of the cohort pre- and postoperatively (Unified Parkinson's Disease Rating Scale [UPDRS] score, Hoehn and Yahr stage, equivalent levodopa daily dose, and tapping test score). RESULTS: We found a significant increase of pain and tolerance mechanical thresholds not only after acute STN-DBS but also after acute levodopa administration. We did not find any significant correlation between postoperative clinical pain improvement and UPDRS-III improvement after acute levodopa or STN-DBS, nor with motor complications improvement assessed with UPDRS-IV after chronic STN-DBS. No correlation was found between postoperative clinical pain improvement and mechanical pain threshold modification. CONCLUSION: Clinical pain alleviation after STN-DBS cannot be considered merely as a consequence of motor complications improvement and could be attributable to a direct central modulation of pain perception, via increased mechanical pain and tolerance thresholds.

Toxoplasmic pachymeningitis with visual field impairment in a single-eyed patient and a literature review.

To describe the clinical features of a patient with toxoplasmic pachymeningitis and provide a review of the recent cases of pachymeningitis in the literature.Retrospective, observational case report. A one-eyed patient who presented to our institution with blurred vision, floaters, and visual field shrinkage. Review of clinical, laboratory, perimetric, and radiologic records of the patient and description of the efficacy of antibiotic therapy. The signs of ocular impairment, including visual acuity, visual field, and magnetic resonance imaging (MRI) changes. A one-eyed patient who complained of blurred vision and unexplained visual field shrinkage was evaluated. The diagnosis of toxoplasmic pachymeningitis was confirmed by existence of a toxoplasmic seroconversion, cerebrospinal fluid abnormalities, radiological features, absence of other diagnoses, improvement of symptoms, and resolution of pachymeningitis in MRI with oral trimethoprim-sulfamethoxazole combination.Pachymeningitis is a rare disease and toxoplasmic pachymeningitis has never been described. Among the various infectious causes, screening for toxoplasmosis must be performed because it can lead to pachymeningitis and sequelae. Variable features may lead to misdiagnosis and delay in the treatment of this sight-threatening and potentially fatal disease.

The combined effect of subthalamic nuclei deep brain stimulation and L-dopa increases emotion recognition in Parkinson's disease.

Deep brain stimulation of the subthalamic nucleus (DBS) is a widely used surgical technique to suppress motor symptoms in Parkinson's disease (PD), and as such improves patients' quality of life. However, DBS may produce emotional disorders such as a reduced ability to recognize emotional facial expressions (EFE). Previous studies have not considered the fact that DBS and l-dopa medication can have differential, common, or complementary consequences on EFE processing. A thorough way of investigating the effect of DBS and l-dopa medication in greater detail is to compare patients' performances after surgery, with the two therapies either being administered ('on') or not administered ('off'). We therefore used a four-condition (l-dopa 'on'/DBS 'on', l-dopa 'on'/DBS 'off', l-dopa 'off'/DBS 'on', and l-dopa 'off'/DBS 'off') EFE recognition paradigm and compared implanted PD patients to healthy controls. The results confirmed those of previous studies, yielding a significant impairment in the detection of some facial expressions relative to controls. Disgust recognition was impaired when patients were 'off' l-dopa and 'on' DBS, and fear recognition impaired when 'off' of both therapies. More interestingly, the combined effect of both DBS and l-dopa administration seems much more beneficial for EFE recognition than the separate administration of each individual therapy. We discuss the implications of these findings in the light of the inverted U curve function that describes the differential effects of dopamine level on the right orbitofrontal cortex (OFC). We propose that, while l-dopa could "overdose" in dopamine the ventral stream of the OFC, DBS would compensate for this over-activation by decreasing OFC activity, thereby restoring the necessary OFC-amygdala interaction. Another finding is that, when collapsing over all treatment conditions, PD patients recognized more neutral faces than the matched controls, a result that concurs with embodiment theories.

Body weight gain and deep brain stimulation.

Deep brain stimulation (DBS) is a neurosurgical technique that has now been available for some 25 years. It is used in the treatment of various motor disorders, e.g. Parkinson's disease (PD), essential tremor and dystonia, and neuropsychiatric illnesses, e.g. obsessive-compulsive disorder and Tourette syndrome. The surgical targets of DBS include the thalamic ventralis intermedius nucleus (Vim), the globus pallidus internus (GPi) and more recently the subthalamic nucleus (STN), currently considered as the reference target in the treatment of PD. In the last ten years, most studies in PD patients have described a rapid and marked weight gain in the months following DBS of the STN. This weight gain sometimes induces obesity and can have metabolic repercussions. The physiopathological mechanisms responsible for the weight gain are multifactorial (changes in energy metabolism and eating behaviour, reduction of motor complications, etc.). This review reports current knowledge concerning weight changes in patients treated by DBS with different surgical targets. It also describes the mechanisms responsible for weight gain and the health outcome for the patients.