Amantadine use in the French prospective NS-Park cohort.

OBJECTIVE: To assess amantadine use and associated factors in the patients with Parkinson's disease (PD). BACKGROUND: Immediate-release amantadine is approved for the treatment of PD and is largely used in clinical practice to treat "levodopa-induced dyskinesia (LIDs). Its use varies according to countries and PD stages. The prospective NS-Park cohort collects features of PD patients followed by 26 French PD Expert Centres. METHODS: Variables used for the analyses included demographics, motor and non-motor PD symptoms and motor complications [motor fluctuations (MFs), LIDs)], antiparkinsonian pharmacological classes and levodopa equivalent daily dose (LEDD). We evaluated: (i) prevalence of amantadine use and compared clinical features of amantadine users vs. non-users (cross-sectional analysis); (ii) factors associated with amantadine initiation (longitudinal analysis); (iii) amantadine effect on LIDs, MFs, apathy, impulse control disorders and freezing of gait (Fog) (longitudinal analysis). RESULTS: Amantadine use prevalence was 12.6% (1,585/12,542, median dose = 200 mg). Amantadine users were significantly younger, with longer and more severe PD symptoms, greater LEDD and more frequent use of device-aided/surgical treatment. Factors independently associated with amantadine initiation were younger age, longer PD duration, more frequent LIDs, MFs and FoG, higher LEDD and better cognitive function. 9 of the 658 patients on amantadine had stopped it at the following visit, after 12-18 months (1.3%). New users of amantadine presented a higher improvement in LIDs and MF compared to amantadine never users. CONCLUSIONS: About 12% of PD patients within the French NS-Park cohort used amantadine, mostly those with younger age and more severe PD. Amantadine initiation was associated with a subsequent reduction in LIDs and MFs.

[Parkinson's disease: intrinsically palliative care]. / La maladie de Parkinson, une prise en soins intrinsèquement palliative.

Multidimensional, chronic, progressive and incurable, Parkinson's disease is, by definition, a palliative disease, and this from the moment of diagnosis. This vision, relatively new to neurology, calls for a paradigm shift, as well as a dual medical-paramedical and home-hospital alliance. This approach allows us to better understand the specificities of Parkinson's disease and its treatments in terms of palliative issues.

Efficacy of dalfampridine in neuromyelitis optica spectrum disorder: A pilot study.

Objective: To assess the efficacy of dalfampridine in patients with neuromyelitis optica spectrum disorder. Methods: We included 15 consecutive patients, who were started on a treatment of dalfampridine 10 mg twice daily for 2 weeks. Efficacy assessment was based on walking ability improvement using Timed-25-Foot Walk and 12-item Multiple Sclerosis Walking Scale tests. Results: The mean Timed-25-Foot Walk score was reduced from 14.8 (±2.4) to 11.3 (±1.9) seconds (p = 0.01). The mean score on the 12-item Multiple Sclerosis Walking Scale was reduced from 41.2 (±3.5) to 31.4 (±3.2) (p = 0.004). Conclusion: Dalfampridine seems to be useful for symptomatic treatment of walking impairment in neuromyelitis optica spectrum disorder.

The impact of subthalamic deep-brain stimulation in restoring motor symmetry in Parkinson's disease patients: a prospective study.

BACKGROUND AND OBJECTIVES: The impact of subthalamic deep-brain stimulation (STN-DBS) on motor asymmetry and its influence on both motor and non-motor outcomes remain unclear. The present study aims at assessing the role of STN-DBS on motor asymmetry and how its modulation translates into benefits in motor function, activities of daily living (ADLs) and quality of life (QoL). METHODS: Postoperative motor asymmetry has been assessed on the multicentric, prospective Predictive Factors and Subthalamic Stimulation in Parkinson's Disease cohort. Asymmetry was evaluated at both baseline (pre-DBS) and 1 year after STN-DBS. A patient was considered asymmetric when the right-to-left MDS-UPDRS part III difference was ≥ 5. In parallel, analyses have been carried out using the absolute right-to-left difference. The proportion of asymmetric patients at baseline was compared to that in the post-surgery evaluation across different medication/stimulation conditions. RESULTS: 537 PD patients have been included. The proportion of asymmetric patients was significantly reduced after both STN-DBS and medication administration (asymmetric patients: 50% in pre-DBS MedOFF, 35% in MedOFF/StimON, 26% in MedON/StimOFF, and 12% in MedON/StimON state). Older patients at surgery and with higher baseline UPDRS II scores were significantly less likely to benefit from STN-DBS at the level of motor asymmetry. No significant correlation between motor asymmetry and ADLs (UPDRS II) or overall QoL (PDQ-39) score was observed. Asymmetric patients had significantly higher mobility, communication, and daily living PDQ-39 sub-scores. CONCLUSIONS: Both STN-DBS and levodopa lead to a reduction in motor asymmetry. Motor symmetry is associated with improvements in certain QoL sub-scores.

Terminal Care in Parkinson's Disease: Real-Life Use of Continuous Subcutaneous Apomorphine Infusion to Improve Patient Comfort.

BACKGROUND: There are currently no recommendations on the therapeutic management of Parkinson's disease (PD) patients at the end of life. OBJECTIVE: To describe a cohort of patients with PD who benefited from continuous subcutaneous apomorphine infusion (CSAI) initiation at the end of their life as comfort care. METHODS: This real-life cohort includes 14 PD patients, who benefited from 24-h, low-dose CSAI (0.5-3 mg/h) in the context of terminal care. Patient's comfort (pain, rigidity, and/or ability to communicate) and occurrence of CSAI-related side-effects (nausea/vomiting, cutaneous and behavioral manifestations) were evaluated based on medical records. RESULTS: All patients (age 62-94 years, disease duration 2-32 years) presented with late-stage PD and a compromised oral route. Treatment lasted from a few hours to 39 days. CSAI led to substantial functional improvement, with a good safety profile. Overall clinical comfort was deemed improved by the medical team, the patient, and/or caregivers. CONCLUSIONS: CSAI might be a promising approach in PD terminal care, as it reduces motor symptoms and overall discomfort, with an apparent good safety profile. Use of the apomorphine pen, sublingual film or a classic syringe pump might be considered when apomorphine pumps are not available. Larger observational cohorts and randomized controlled trials are needed to establish the efficacy and tolerability of apomorphine in the context of terminal care and more broadly, in an advance care planning perspective.

Motivational and cognitive predictors of apathy after subthalamic nucleus stimulation in Parkinson's disease.

Postoperative apathy is a frequent symptom in Parkinson's disease patients who have undergone bilateral deep brain stimulation of the subthalamic nucleus. Two main hypotheses for postoperative apathy have been suggested: (i) dopaminergic withdrawal syndrome relative to postoperative dopaminergic drug tapering; and (ii) direct effect of chronic stimulation of the subthalamic nucleus. The primary objective of our study was to describe preoperative and 1-year postoperative apathy in Parkinson's disease patients who underwent chronic bilateral deep brain stimulation of the subthalamic nucleus. We also aimed to identify factors associated with 1-year postoperative apathy considering: (i) preoperative clinical phenotype; (ii) dopaminergic drug management; and (iii) volume of tissue activated within the subthalamic nucleus and the surrounding structures. We investigated a prospective clinical cohort of 367 patients before and 1 year after chronic bilateral deep brain stimulation of the subthalamic nucleus. We assessed apathy using the Lille Apathy Rating Scale and carried out a systematic evaluation of motor, cognitive and behavioural signs. We modelled the volume of tissue activated in 161 patients using the Lead-DBS toolbox and analysed overlaps within motor, cognitive and limbic parts of the subthalamic nucleus. Of the 367 patients, 94 (25.6%) exhibited 1-year postoperative apathy: 67 (18.2%) with 'de novo apathy' and 27 (7.4%) with 'sustained apathy'. We observed disappearance of preoperative apathy in 22 (6.0%) patients, who were classified as having 'reversed apathy'. Lastly, 251 (68.4%) patients had neither preoperative nor postoperative apathy and were classified as having 'no apathy'. We identified preoperative apathy score [odds ratio (OR) 1.16; 95% confidence interval (CI) 1.10, 1.22; P < 0.001], preoperative episodic memory free recall score (OR 0.93; 95% CI 0.88, 0.97; P = 0.003) and 1-year postoperative motor responsiveness (OR 0.98; 95% CI 0.96, 0.99; P = 0.009) as the main factors associated with postoperative apathy. We showed that neither dopaminergic dose reduction nor subthalamic stimulation were associated with postoperative apathy. Patients with 'sustained apathy' had poorer preoperative fronto-striatal cognitive status and a higher preoperative action initiation apathy subscore. In these patients, apathy score and cognitive status worsened postoperatively despite significantly lower reduction in dopamine agonists (P = 0.023), suggesting cognitive dopa-resistant apathy. Patients with 'reversed apathy' benefited from the psychostimulant effect of chronic stimulation of the limbic part of the left subthalamic nucleus (P = 0.043), suggesting motivational apathy. Our results highlight the need for careful preoperative assessment of motivational and cognitive components of apathy as well as executive functions in order to better prevent or manage postoperative apathy.

Imbalanced motivated behaviors according to motor sign asymmetry in drug-naïve Parkinson's disease.

Few studies have considered the influence of motor sign asymmetry on motivated behaviors in de novo drug-naïve Parkinson's disease (PD). We tested whether motor sign asymmetry could be associated with different motivated behavior patterns in de novo drug-naïve PD. We performed a cross-sectional study in 128 de novo drug-naïve PD patients and used the Ardouin Scale of Behavior in Parkinson's disease (ASBPD) to assess a set of motivated behaviors. We assessed motor asymmetry based on (i) side of motor onset and (ii) MDS-UPDRS motor score, then we compared right hemibody Parkinson's disease to left hemibody Parkinson's disease. According to the MDS-UPDRS motor score, patients with de novo right hemibody PD had significantly lower frequency of approach behaviors (p = 0.031), including nocturnal hyperactivity (p = 0.040), eating behavior (p = 0.040), creativity (p = 0.040), and excess of motivation (p = 0.017) than patients with de novo left hemibody PD. Patients with de novo left hemibody PD did not significantly differ from those with de novo right hemibody PD regarding avoidance behaviors including apathy, anxiety and depression. Our findings suggest that motor sign asymmetry may be associated with an imbalance between motivated behaviors in de novo drug-naïve Parkinson's disease.

Overview on wearable sensors for the management of Parkinson's disease.

Parkinson's disease (PD) is affecting about 1.2 million patients in Europe with a prevalence that is expected to have an exponential increment, in the next decades. This epidemiological evolution will be challenged by the low number of neurologists able to deliver expert care for PD. As PD is better recognized, there is an increasing demand from patients for rigorous control of their symptoms and for therapeutic education. In addition, the highly variable nature of symtoms between patients and the fluctuations within the same patient requires innovative tools to help doctors and patients monitor the disease in their usual living environment and adapt treatment in a more relevant way. Nowadays, there are various body-worn sensors (BWS) proposed to monitor parkinsonian clinical features, such as motor fluctuations, dyskinesia, tremor, bradykinesia, freezing of gait (FoG) or gait disturbances. BWS have been used as add-on tool for patients' management or research purpose. Here, we propose a practical anthology, summarizing the characteristics of the most used BWS for PD patients in Europe, focusing on their role as tools to improve treatment management. Consideration regarding the use of technology to monitor non-motor features is also included. BWS obviously offer new opportunities for improving management strategy in PD but their precise scope of use in daily routine care should be clarified.

Apathy in Parkinson's Disease: Clinical Patterns and Neurobiological Basis.

Apathy is commonly defined as a loss of motivation leading to a reduction in goal-directed behaviors. This multidimensional syndrome, which includes cognitive, emotional and behavioral components, is one of the most prevalent neuropsychiatric features of Parkinson's disease (PD). It has been established that the prevalence of apathy increases as PD progresses. However, the pathophysiology and anatomic substrate of this syndrome remain unclear. Apathy seems to be underpinned by impaired anatomical structures that link the prefrontal cortex with the limbic system. It can be encountered in the prodromal stage of the disease and in fluctuating PD patients receiving bilateral chronic subthalamic nucleus stimulation. In these stages, apathy may be considered as a disorder of motivation that embodies amotivational behavioral syndrome, is underpinned by combined dopaminergic and serotonergic denervation and is dopa-responsive. In contrast, in advanced PD patients, apathy may be considered as cognitive apathy that announces cognitive decline and PD dementia, is underpinned by diffuse neurotransmitter system dysfunction and Lewy pathology spreading and is no longer dopa-responsive. In this review, we discuss the clinical patterns of apathy and their treatment, the neurobiological basis of apathy, the potential role of the anatomical structures involved and the pathways in motivational and cognitive apathy.

Effects of deep brain stimulation frequency on eye movements and cognitive control.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for Parkinson's disease (PD). Varying the frequency DBS has differential effects on axial and distal limb functions, suggesting differing modulation of relevant pathways. The STN is also a critical node in oculomotor and associative networks, but the effect of stimulation frequency on these networks remains unknown. This study aimed to investigate the effects of 80 hz vs. 130 Hz frequency STN-DBS on eye movements and executive control. Twenty-one STN-DBS PD patients receiving 130 Hz vs. 80 Hz stimulation were compared to a healthy control group (n = 16). All participants were tested twice in a double-blind manner. We examined prosaccades (latency and gain) and antisaccades (latency of correct and incorrect antisaccades, error rate and gain of the correct antisaccades). Executive function was tested with the Stroop task. The motor condition was assessed using Unified Parkinson's Disease Rating Scale part III. The antisaccadic error rate was higher in patients (p = 0.0113), more so in patients on 80 Hz compared to 130 Hz (p = 0.001) stimulation. The differences between patients and controls and between frequencies for all other eye-movements or cognitive measures were not statistically significant. We show that 80 Hz STN-DBS in PD reduces the ability to maintain stable fixation but does not alter inhibition, resulting in a higher antisaccade error rate presumably due to less efficient fixation, without altering the motor state. This provides a wider range of stimulation parameters that can reduce specific DBS-related effects without affecting motor outcomes.

Symptoms assessment and decision to treat patients with advanced Parkinson's disease based on wearables data.

Body-worn sensors (BWS) could provide valuable information in the management of Parkinson's disease and support therapeutic decisions based on objective monitoring. To study this pivotal step and better understand how relevant information is extracted from BWS results and translated into treatment adaptation, eight neurologists examined eight virtual cases composed of basic patient profiles and their BWS monitoring results. Sixty-four interpretations of monitoring results and the subsequent therapeutic decisions were collected. Relationship between interrater agreements in the BWS reading and the severity of symptoms were analyzed via correlation studies. Logistic regression was used to identify associations between the BWS parameters and suggested treatment modifications. Interrater agreements were high and significantly associated with the BWS scores. Summarized BWS scores reflecting bradykinesia, dyskinesia, and tremor predicted the direction of treatment modifications. Our results suggest that monitoring information is robustly linked to treatment adaptation and pave the way to loop systems able to automatically propose treatment modifications from BWS recordings information.

Fatigue in de novo Parkinson's Disease: Expanding the Neuropsychiatric Triad?

BACKGROUND: Fatigue is a frequent and troublesome symptom present from the early stages of Parkinson's disease (PD). OBJECTIVE: To examine the relationship between fatigue and the neuropsychiatric triad, which includes apathy, depression, and anxiety, in de novo PD. METHODS: We performed a cross-sectional study including 197 patients with de novo PD and assessed fatigue using the Parkinson's Disease Fatigue Scale (PDFS-16). We evaluated motor status using the Unified Parkinson's Disease Rating Scale (UPDRS) part III score and evaluated neuropsychiatric status using the Ardouin Scale of Behavior in Parkinson's Disease (ASBPD). We carried out univariate and multivariate analyses to model association between motor signs, non-motor signs, and fatigue risk. RESULTS: Frequency of fatigue (28.9%) was of the same order of magnitude as that of apathy. PD patients with fatigue reported a lower quality of life than patients without fatigue (p < 0.0001). The ASBPD showed that patients with fatigue had higher scores for depressed mood (p < 0.0001), anxiety (p < 0.0001), and apathy (p < 0.0001). In the univariate analysis, fatigue score was positively correlated with apathy, depression, anxiety, and the neuropsychiatric triad as a whole, and to a lesser extent with female sex, hyperemotivity, and the UPDRS part III score. In the multivariate analysis, after adjusting for sex and motor status, the fatigue score remained significantly correlated with apathy (OR = 11.17 [4.33-28.78], p < 0.0001) and depression (OR = 4.28 [1.39-13.12], p = 0.01), but not with anxiety (OR = 0.94 [0.34-2.58], p = 0.9). CONCLUSION: We propose that the neuropsychiatric triad could be expanded to include fatigue.

A French survey on the lockdown consequences of COVID-19 pandemic in Parkinson's disease. The ERCOPARK study.

BACKGROUND: In 2020 the coronavirus disease 19 (COVID-19) pandemic imposed a total and sudden lockdown. We aimed to investigate the consequences of the first COVID-19 lockdown (mid-March - mid-April 2020) on motor and non-motor symptoms (NMS) in a cohort of French people with Parkinson's disease (PwP). METHODS: PwP were enrolled either by an on-line survey sent from the national France Parkinson association (FP) to reach the French community of PwP or as part of outpatients' telemedicine visits followed by an hospital-based Parkinson Expert Center (PEC). All patients were evaluated using the same standardized questionnaire assessing motor and NMS (including a list of most disabling, new or worsened symptoms and Patient's Global Impression-Improvement scales [PGI-I]) psycho-social queries and quality of life. RESULTS: 2653 PwP were included: 441 (16.6%) in the PEC group and 2122 (83.4%) in the community-based group. Physiotherapy was interrupted among 88.6% of the patients. 40.9% referred a clinical modification of their symptoms. Based on the questionnaire, pain (9.3%), rigidity (9.1%) and tremor (8.5%) were the three most frequently new or worsened reported symptoms. Based on the PGI-I, the motor symptoms were the most affected domain, followed by pain and psychic state. PwP in community-based group tended to have more frequent worsening for motor symptoms, motor complications, pain and confusion than those of the PEC group. CONCLUSIONS: The first COVID-19 lockdown had a negative impact on motor and NMS of PwP. Efforts should be allocated to avoid interruption of care, including physiotherapy and physical activities and implement telemedicine. .

Repetitive Transcranial Magnetic Stimulation as an Add-On Treatment for Cognitive Impairment in Alzheimer's Disease and Its Impact on Self-Rated Quality of Life and Caregiver's Burden.

Alzheimer's disease (AD) is associated with progressive memory loss and decline in executive functions, as well as neuropsychiatric symptoms. Patients usually consider quality of life (QoL) and mood as more important for their health status than disease-specific physical and mental symptoms. In this open-label uncontrolled trial, 12 subjects diagnosed with AD underwent 10 sessions of repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (10 Hz, 20 min, 2000 pulses/day, 110% MT). Outcomes were measured before and 30 days after treatment. Our primary objective was to test the efficacy of rTMS as an add-on treatment for AD on the global cognitive function, assessed through the Mini-Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (MDRS). As secondary objectives, the detailed effect on cognitive functions, depression and anxiety symptoms, QoL, and functionality in daily life activities were evaluated, as well as correlations between QoL and cognition, depression and anxiety scores. The treatment significantly enhanced semantic memory and reduced anxiety. Improvement of these features in AD could become an important target for treatment strategies. Although limited by its design, this trial may contribute with another perspective on the analysis and the impact of rTMS on AD.

Robot-induced hallucinations in Parkinson's disease depend on altered sensorimotor processing in fronto-temporal network.

Hallucinations in Parkinson's disease (PD) are disturbing and frequent non-motor symptoms and constitute a major risk factor for psychosis and dementia. We report a robotics-based approach applying conflicting sensorimotor stimulation, enabling the induction of presence hallucinations (PHs) and the characterization of a subgroup of patients with PD with enhanced sensitivity for conflicting sensorimotor stimulation and robot-induced PH. We next identify the fronto-temporal network of PH by combining MR-compatible robotics (and sensorimotor stimulation in healthy participants) and lesion network mapping (neurological patients without PD). This PH-network was selectively disrupted in an additional and independent cohort of patients with PD, predicted the presence of symptomatic PH, and associated with cognitive decline. These robotics-neuroimaging findings extend existing sensorimotor hallucination models to PD and reveal the pathological cortical sensorimotor processes of PH in PD, potentially indicating a more severe form of PD that has been associated with psychosis and cognitive decline.

Geospatial analysis of individual-based Parkinson's disease data supports a link with air pollution: A case-control study.

BACKGROUND: The etiology of Parkinson's disease (PD) remains unknown. To approach the issue of PD's risk factors from a new perspective, we hypothesized that coupling the geographic distribution of PD with spatial statistics may provide new insights into environmental epidemiology research. The aim of this case-control study was to examine the spatial dependence of PD prevalence in the Canton of Geneva, Switzerland (population = 474,211). METHODS: PD cases were identified through Geneva University Hospitals, private neurologists and nursing homes medical records (n = 1115). Controls derived from a population-based study (n = 12,614) and a comprehensive population census dataset (n = 237,771). All individuals were geographically localized based on their place of residence. Spatial Getis-Ord Gi* statistics were used to identify clusters of high versus low disease prevalence. Confounder-adjustment was performed for age, sex, nationality and income. Tukey's honestly significant difference was used to determine whether nitrogen dioxide and particulate matters PM10 concentrations were different within PD hotspots, coldspots or neutral areas. RESULTS: Confounder-adjustment greatly reduced greatly the spatial association. Characteristics of the geographic space influenced PD prevalence in 6% of patients. PD hotspots were concentrated in the urban centre. There was a significant difference in mean annual nitrogen dioxide and PM10 levels (+3.6 µg/m3 [p < 0.001] and +0.63 µg/m3 [p < 0.001] respectively) between PD hotspots and coldspots. CONCLUSION: PD prevalence exhibited a spatial dependence for a small but significant proportion of patients. A positive association was detected between PD clusters and air pollution. Our data emphasize the multifactorial nature of PD and support a link between PD and air pollution.

Impact of Subthalamic Deep Brain Stimulation on Impulse Control Disorders in Parkinson's Disease: A Prospective Study.

BACKGROUND: Impact of subthalamic deep brain stimulation (DBS) on impulse control disorders (ICD) in Parkinson's disease (PD) remains controversial. OBJECTIVES: The objectives of this study were to analyze the natural history of ICD between baseline and 1 year after subthalamic DBS in patients with PD and to identify predictive factors, taking into account the positions of the active contact and stimulation parameters. METHODS: We analyzed postoperative modifications of ICD based on the multicentric, prospective Predictive Factors and Subthalamic Stimulation in Parkinson's Disease cohort. ICD status and Ardouin Scale of Behaviour in PD were assessed at baseline and 1 year following subthalamic DBS. Location of active contacts within the 3 subthalamic nucleus functional territories was investigated. RESULTS: A total of 217 were patients included. Of the patients, 10.6% had ICD at baseline of which 95.6% improved at 1 year following subthalamic DBS; 3.6% of the patients experienced de novo ICD at 1 year following subthalamic DBS. Dopamine agonist dose reduction (from 309.8 to 109.3 mg) was the main driver of ICD regression (P = 0.05). Higher preoperative dyskinesias were associated with poorer ICD evolution (P = 0.04). Whereas baseline apathy was a risk factor of de novo ICD (P = 0.02), ICD improvement correlated with postoperative apathy (P = 0.004). Stimulation power and position of active contacts-mainly located within the sensorimotor part of the subthalamic nucleus-did not influence ICD. CONCLUSIONS: This 1-year, postoperative follow-up study showed ICD regression and dopaminergic drug reduction with optimal position of the active contacts within the subthalamic nucleus. Whereas patients with PD with preoperative ICD were prone to postoperative apathy, we also showed that those with preoperative apathy had a higher risk to experience postoperative de novo ICD, further highlighting the meaningful influence of postoperative management of dopaminergic medication on outcome and the continuum between apathy and ICD. © 2020 International Parkinson and Movement Disorder Society.

[Aging and disorders of taste and smell]. / Vieillissement et troubles du goût et de l'olfaction.

Compared with other sensory modalities, age-related alterations in taste and smell are less known and less investigated in clinical practice. In fact, the elderly with a loss of smell or taste may not always report it or be aware of it. In addition, the clinical evaluation of taste and smell by specific tests is rarely performed.

Modeling of Electric Fields in Individual Imaging Atlas for Capsular Threshold Prediction of Deep Brain Stimulation in Parkinson's Disease: A Pilot Study.

Background: Modeling of deep brain stimulation electric fields and anatomy-based software might improve post-operative management of patients with Parkinson's disease (PD) who have benefitted from subthalamic nucleus deep brain stimulation (STN-DBS). Objective: We compared clinical and software-guided determination of the thresholds for current diffusion to the pyramidal tract, the most frequent limiting side effect in post-operative management of STN-DBS PD patients. Methods: We assessed monopolar reviews in 16 consecutive STN-DBS PD patients and retrospectively compared clinical capsular thresholds, which had been assessed according to standard clinical practice, to those predicted by volume of tissue activated (VTA) model software. All the modeling steps were performed blinded from patients' clinical evaluations. Results: At the group level, we found a significant correlation (p = 0.0001) when performing statistical analysis on the z-scored capsular thresholds, but with a low regression coefficient (r = 0.2445). When considering intra-patient analysis, we found significant correlations (p < 0.05) between capsular threshold as modeled with the software and capsular threshold as determined clinically in five patients (31.2%). Conclusions: In this pilot study, the VTA model software was of limited assistance in identifying capsular thresholds for the whole cohort due to a large inter-patient variability. Clinical testing remains the gold standard in selecting stimulation parameters for STN-DBS in PD.