Development and validation of the DBS-PS (Deep Brain Stimulation-Perception Scale): Assessing parkinsonian patients' expectations to prevent post-operative disappointment?

BACKGROUND: Recent literature suggests that taking into consideration and evaluating preoperative expectations of Parkinson's disease (PD) patients candidates to deep brain stimulation (DBS), can contribute to treatment effectiveness. However, few validated instruments investigating preoperative expectations are available. We present the development and validation of the DBS-PS (Deep Brain Stimulation - Perception Scale). METHODS: The DBS-PS is an 11 questions self-administered scale, with answers rated on a 10-point Likert scale (1 completely false, 10 completely true). Items were generated on the basis of patient's interviews analyzed by an expert group and reached consensus. The scale is divided into three domains: expectations for PD, expectations for social-life and leisure, expectations for intimate life. Exploratory factor analysis (EFA) completed by item response theory (IRT) analysis was conducted to validate the theoretical structure of the DBS-PS. RESULTS: 64 PD patients aged 59.18 (SD = 5.74) years with PD diagnosed since 9.36 (SD = 4.09) years completed the DBS-PS preoperatively. EFA confirmed a 3 factors scale structure (eigenvalue >1) explaining 69% of variance (factor 1: 43%; factor 2: 17%; factor 3: 9%). Reliability (Cronbach's α: 0.714 for factor 1, 0.781 for factor 2, 0.889 for factor 3) and discriminant validity (Pearson coefficient r < 0.50) were satisfactory. IRT showed good model fit, preserved unidimensionality, but some local dependences were observed. CONCLUSION: The DBS-PS shows satisfactory psychometric properties. It is easy to administer in routine practice with preoperative PD patients. It constitutes an interesting basis for cognitive restructuring before neurosurgery, by highlighting dysfunctional cognitions and measuring the benefits of cognitive restructuring therapy.

Sustained reduction of essential tremor with low-power non-thermal transcranial focused ultrasound stimulations in humans.

BACKGROUND: Transcranial ultrasound stimulation (TUS) is a non-invasive brain stimulation technique; when skull aberrations are compensated for, this technique allows, with millimetric accuracy, circumvention of the invasive surgical procedure associated with deep brain stimulation (DBS) and the limited spatial specificity of transcranial magnetic stimulation. OBJECTIVE: /hypothesis: We hypothesize that MR-guided low-power TUS can induce a sustained decrease of tremor power in patients suffering from medically refractive essential tremor. METHODS: The dominant hand only was targeted, and two anatomical sites were sonicated in this exploratory study: the ventral intermediate nucleus of the thalamus (VIM) and the dentato-rubro-thalamic tract (DRT). Patients (N = 9) were equipped with MR-compatible accelerometers attached to their hands to monitor their tremor in real-time during TUS. RESULTS: VIM neurostimulations followed by a low-duty cycle (5 %) DRT stimulation induced a substantial decrease in the tremor power in four patients, with a minimum of 89.9 % reduction when compared with the baseline power a few minutes after the DRT stimulation. The only patient stimulated in the VIM only and with a low duty cycle (5 %) also experienced a sustained reduction of the tremor (up to 93.4 %). Four patients (N = 4) did not respond. The temperature at target was 37.2 ± 1.4 °C compared to 36.8 ± 1.4 °C for a 3 cm away control point. CONCLUSIONS: MR-guided low power TUS can induce a substantial and sustained decrease of tremor power. Follow-up studies need to be conducted to reproduce the effect and better to understand the variability of the response amongst patients. MR thermometry during neurostimulations showed no significant thermal rise, supporting a mechanical effect.

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.

ON/OFF non-motor evaluation: a new way to evaluate non-motor fluctuations in Parkinson's disease.

BACKGROUND: NMF are currently poorly evaluated in therapeutic decisions. A quantification of their severity would facilitate their integration. The objective of this study was to validate an autoquestionnaire evaluating the severity of non-motor fluctuations (NMF) in Parkinson's disease (PD). METHODS: Patients with PD were included in presurgical situation for deep brain stimulation of subthalamic nuclei. They participated in the PREDISTIM cohort (a study evaluating the predictive factors for therapeutic response of subthalamic stimulation in PD) in 17 centres in France. Our questionnaire, resulting from previous phases of development, included 11 non-motor symptoms (NMS). Their severity ranged from 0 to 10 and was assessed in OFF and then ON-Dopa to study their fluctuations. RESULTS: 310 patients were included, of whom 98.8% had NMS and 98.0% had NMF. Each NMS was significantly improved by L-Dopa (decrease in severity score ranging from 43.1% to 69.9%). Fatigue was the most frequent and most severe NMS. NMS were considered more bothersome than motor symptoms by 37.5% of patients in OFF-Dopa and 34.9% in ON-Dopa. CONCLUSIONS: This is the first questionnaire allowing a real-time quantification of the severity of NMS and their fluctuation with levodopa. It was able to confirm and measure the effect of L-dopa and show differences according to the patients and the NMS. It differs from other questionnaires by its measurement at a precise moment of the severity of the NMS, allowing its use during pretherapeutic assessments.Our questionnaire has been validated to measure the severity of NMF. It will be able to quantify the non-motor effect of anti-parkinsonian treatments and could facilitate the integration of NMF in therapeutic decisions.

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.

Freezing of gait depends on cortico-subthalamic network recruitment following STN-DBS in PD patients.

INTRODUCTION: Subthalamic deep-brain-stimulation (STN-DBS) is an effective means to treat Parkinson's disease (PD) symptoms. Its benefit on gait disorders is variable, with freezing of gait (FOG) worsening in about 30% of cases. Here, we investigate the clinical and anatomical features that could explain post-operative FOG. METHODS: Gait and balance disorders were assessed in 19 patients, before and after STN-DBS using clinical scales and gait recordings. The location of active stimulation contacts were evaluated individually and the volumes of activated tissue (VAT) modelled for each hemisphere. We used a whole brain tractography template constructed from another PD cohort to assess the connectivity of each VAT within the 39 Brodmann cortical areas (BA) to search for correlations between postoperative PD disability and cortico-subthalamic connectivity. RESULTS: STN-DBS induced a 100% improvement to a 166% worsening in gait disorders, with a mean FOG decrease of 36%. We found two large cortical clusters for VAT connectivity: one "prefrontal", mainly connected with BA 8,9,10,11 and 32, and one "sensorimotor", mainly connected with BA 1-2-3,4 and 6. After surgery, FOG severity positively correlated with the right prefrontal VAT connectivity, and negatively with the right sensorimotor VAT connectivity. The right prefrontal VAT connectivity also tended to be positively correlated with the UPDRS-III score, and negatively with step length. The MDRS score positively correlated with the right sensorimotor VAT connectivity. CONCLUSION: Recruiting right sensorimotor and avoiding right prefrontal cortico-subthalamic fibres with STN-DBS could explain reduced post-operative FOG, since gait is a complex locomotor program that necessitates accurate cognitive control.

Personality assessment with Temperament and Character Inventory in Parkinson's disease.

INTRODUCTION: There is a growing interest in personality evaluation in Parkinson's disease (PD), following observations of specific temperaments in PD patients. Therefore, our objective was to evaluate personality dimensions from the Temperament and Character Inventory (TCI) in a cohort of fluctuating PD patients considered for deep brain stimulation. METHODS: Fluctuating PD patients from the PREDISTIM cohort were included. Description of TCI dimensions and comparison with a French normative cohort were performed. Pearson correlations between TCI dimensions and motor, behavioral and cognitive variables were investigated. Structural and internal consistency analysis of the TCI were further assessed. RESULTS: The 570 PD patients presented significant higher scores in Harm Avoidance, Reward Dependence, Persistence, Self-Directedness and Cooperativeness and significant lower scores in Self-Transcendence compared to the French normative cohort; only Novelty Seeking scores were not different. Harm Avoidance and Self-directedness scores were correlated with PDQ-39 total, HAMD, HAMA scores, and anxiolytic/antidepressant treatment. Novelty Seeking scores were correlated with impulsivity. Pearson correlations between TCI dimensions, principal component analysis of TCI sub-dimensions and Cronbach's alpha coefficients showed adequate psychometric proprieties. CONCLUSION: The TCI seems to be an adequate tool to evaluate personality dimensions in PD with good structural and internal consistencies. These fluctuating PD patients also have specific personality dimensions compared to normative French population. Moreover, Harm Avoidance and Self-Directedness scores are associated with anxio-depressive state or quality of life and, and Novelty Seeking scores with impulsivity.

Can Dopamine Responsiveness Be Predicted in Parkinson's Disease Without an Acute Administration Test?

BACKGROUND: Dopamine responsiveness (dopa-sensitivity) is an important parameter in the management of patients with Parkinson's disease (PD). For quantification of this parameter, patients undergo a challenge test with acute Levodopa administration after drug withdrawal, which may lead to patient discomfort and use of significant resources. OBJECTIVE: Our objective was to develop a predictive model combining clinical scores and imaging. METHODS: 350 patients, recruited by 13 specialist French centers and considered for deep brain stimulation, underwent an acute L-dopa challenge (dopa-sensitivity > 30%), full assessment, and MRI investigations, including T1w and R2* images. Data were randomly divided into a learning base from 10 centers and data from the remaining centers for testing. A machine selection approach was applied to choose the optimal variables and these were then used in regression modeling. Complexity of the modelling was incremental, while the first model considered only clinical variables, the subsequent included imaging features. The performances were evaluated by comparing the estimated values and actual valuesResults:Whatever the model, the variables age, sex, disease duration, and motor scores were selected as contributors. The first model used them and the coefficients of determination (R2) was 0.60 for the testing set and 0.69 in the learning set (p < 0.001). The models that added imaging features enhanced the performances: with T1w (R2 = 0.65 and 0.76, p < 0.001) and with R2* (R2 = 0.60 and 0.72, p < 0.001). CONCLUSION: These results suggest that modeling is potentially a simple way to estimate dopa-sensitivity, but requires confirmation in a larger population, including patients with dopa-sensitivity < 30.

Heterogeneity of PD-MCI in Candidates to Subthalamic Deep Brain Stimulation: Associated Cortical and Subcortical Modifications.

BACKGROUND: Parkinson's disease mild cognitive impairment (PD-MCI) is frequent and heterogenous. There is no consensus about its influence on subthalamic deep brain stimulation (STN-DBS) outcomes. OBJECTIVE: To determine the prevalence of PD-MCI and its subtypes in candidates to STN-DBS. Secondarily, we sought to identify MRI structural markers associated with cognitive impairment in these subgroups. METHODS: Baseline data from the French multicentric PREDISTIM cohort were used. Candidates to STN-DBS were classified according to their cognitive performance in normal cognition (PD-NC) or PD-MCI. The latter included frontostriatal (PD-FS) and posterior cortical (PD-PC) subtypes. Between-group comparisons were performed on demographical and clinical variables as well as on T1-weighted MRI sequences at the cortical and subcortical levels. RESULTS: 320 patients were included: 167 (52%) PD-NC and 153 (48%) PD-MCI patients. The latter group included 123 (80%) PD-FS and 30 (20%) PD-PC patients. There was no between-group difference regarding demographic and clinical variables. PD-PC patients had significantly lower global efficiency than PD-FS patients and significantly worse performance on visuospatial functions, episodic memory, and language. Compared to PD-NC, PD-MCI patients had cortical thinning and radiomic-based changes in the left caudate nucleus and hippocampus. There were no significant differences between the PD-MCI subtypes. CONCLUSION: Among the candidates to STN-DBS, a significant proportion has PD-MCI which is associated with cortical and subcortical alterations. Some PD-MCI patients have posterior cortical deficits, a subtype known to be at higher risk of dementia.

Design and Simulation of a Passive Absorber to Reduce Measured Postural Tremor Signal.

Tremor is a semirhythmic oscillatory movement of a body part caused by alternating simultaneous contractions of an antagonistic muscle group. Medical and surgical treatments used to reduce the symptoms of involuntary tremor can cause negative side effects. This study examined the ability of passive vibration absorbers in reducing the amplitude of postural tremor (PT). Inertial measurement unit (IMU) was used to record PT signals at the forearm and hand of a patient. IMU signal was used to excite an upper limb modeled to represent the flexion-extension vibrational motion at the joints. Equations of motion were solved numerically to obtain a response that fits the measured tremor signal. Passive tuned mass damper (TMD) was modeled as a cantilever beam and a screw placed along its length, at a position reflecting its operational frequency. Natural frequency of the TMD was derived for different mass positions and validated numerically and experimentally. Modal damping ratio of the TMD, for each mass position, was also estimated. Mass position and damping coefficient of the TMD were optimized depending on the minimization in the power spectral density (PSD) of angular displacement amplitude at the wrist joint. Optimized three-TMD system of 28.64 g total effective mass with the estimated modal damping ratio reduced 83.1% of the PSD of the angular displacement amplitude. This study showed the performance ability of a lightweight passive absorber in controlling the involuntary tremor of a system excited by the measured tremor signal of a patient.

Personality Related to Quality-of-Life Improvement After Deep Brain Stimulation in Parkinson's Disease (PSYCHO-STIM II).

BACKGROUND: Deep brain stimulation of the sub-thalamic nucleus (DBS-STN) reduces symptoms in Parkinson's disease (PD) patients with motor fluctuations. However, some patients may not feel ameliorated afterwards, despite an objective motor improvement. It is thus important to find new predictors of patients' quality of life (QoL) amelioration after DBS-STN. We hypothesized that personality dimensions might affect QoL after DBS-STN. OBJECTIVE: To evaluate associations between personality dimensions and QoL improvement one year after DBS-STN. METHODS: DBS-STN-PD patients (n = 303) having answered the "Temperament and Character Inventory" (TCI) before surgery and the PDQ-39 before and one year after surgery were included, from the cohort study PREDI-STIM. Linear regression models were used to evaluate associations between TCI dimensions and change in PDQ-39 scores after DBS-STN. RESULTS: Novelty Seeking and Cooperativeness scores before surgery were positively associated with PDQ-39 scores improvement after DBS-STN (FDR-adjusted p < 0.01). Moreover, paradoxically unimproved patients with deterioration of their PDQ-39 scores after DBS-STN despite improvement of their MDS-UPDRS-IV scores had lower Cooperativeness scores, while paradoxically improved patients with amelioration of their PDQ-39 scores despite deterioration of their MDS-UPDRS-IV scores had higher Reward Dependence scores. CONCLUSION: Some presurgical personality dimensions were significantly associated with QoL amelioration and discrepancy between motor state and QoL changes after DBS-STN in PD. Educational programs before DBS-STN should take in account patient personality dimensions to better deal with their expectations.

Preoperative REM Sleep Behavior Disorder and Subthalamic Nucleus Deep Brain Stimulation Outcome in Parkinson Disease 1 Year After Surgery.

BACKGROUND AND OBJECTIVES: To determine whether patients with Parkinson disease (PD) eligible for subthalamic nucleus deep brain stimulation (STN-DBS) with probable REM sleep behavior disorder (RBD) preoperatively could be more at risk of poorer motor, nonmotor, and quality of life outcomes 12 months after surgery compared to those without RBD. METHODS: We analyzed the preoperative clinical profile of 448 patients with PD from a French multicentric prospective study (PREDISTIM) according to the presence or absence of probable RBD based on the RBD Single Question and RBD Screening Questionnaire. Among the 215 patients with PD with 12 months of follow-up after STN-DBS, we compared motor, cognitive, psycho-behavioral profile, and quality of life outcomes in patients with (pre-opRBD+) or without (pre-opRBD-) probable RBD preoperatively. RESULTS: At preoperative evaluation, pre-opRBD+ patients were older (61 ± 7.2 vs 59.5 ± 7.7 years; p = 0.02), had less motor impairment (Movement Disorder Society-sponsored version of the Unified Parkinson's Disease Rating Scale [MDS-UPDRS] III "off": 38.7 ± 16.2 vs 43.4 ± 7.1; p = 0.03) but more nonmotor symptoms on daily living activities (MDS-UPDRS I: 12.6 ± 5.5 vs 10.7 ± 5.3; p < 0.001), had more psychobehavioral manifestations (Ardouin Scale of Behavior in Parkinson's Disease total: 7.7 ± 5.1 vs 5.1 ± 0.4; p = 0.003), and had worse quality of life (Parkinson's Disease Questionnaire-39: 33 ± 12 vs 29 ± 12; p = 0.03), as compared to pre-opRBD- patients. Both pre-opRBD+ and pre-opRBD- patients had significant MDS-UPDRS IV score decrease (-37% and -33%, respectively), MDS-UPDRS III "med 'off'/stim 'on'" score decrease (-52% and -54%), and dopaminergic treatment decrease (-52% and -49%) after surgery, with no between-group difference. There was no between-group difference for cognitive and global quality of life outcomes. CONCLUSIONS: In patients with PD eligible for STN-DBS, the presence of probable RBD preoperatively is not associated with a different clinical outcome 1 year after neurosurgery. TRIAL REGISTRATION INFORMATION: NCT02360683. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that in patients with PD eligible for STN-DBS, the presence of probable RBD preoperatively is not associated with poorer outcomes 1 year post surgery.

Long-term effect of apomorphine infusion in advanced Parkinson's disease: a real-life study.

Long-term effects of continuous subcutaneous apomorphine infusion (CSAI) on health-related quality of life (HRQoL) and predictors of CSAI discontinuation are poorly known. Data from consecutive advanced Parkinson's disease patients treated in routine care were retrospectively collected over 24 months after CSAI initiation, with a focus on the 39-item Parkinson's disease questionnaire (PDQ-39). We determined predictors of CSAI discontinuation and HRQoL improvement using multiple regression analysis. Of the 110 subjects evaluated over a 2-year period, 35% discontinued CSAI. Of those who continued treatment, HRQoL remained stable with a sustained reduction in motor fluctuations. The observed effect on dyskinesias was mild and transient. Of note, patients with preexisting impulse control disorders showed an overall good tolerability. PDQ-39 was the only baseline predictor of HRQoL improvement after 2 years of treatment. The presence of dyskinesias, poorer psychological status, shorter disease duration, male sex, and worse OFF state were predictors of discontinuation. Best candidates for CSAI are patients with: (i) poor baseline HRQoL and (ii) marked motor fluctuations.

Personality dimensions of patients can change during the course of parkinson's disease.

BACKGROUND: Studies assessing personality dimensions by the "Temperament and Character Inventory" (TCI) have previously found an association between Parkinson's disease (PD) and lower Novelty Seeking and higher Harm Avoidance scores. Here, we aimed to describe personality dimensions of PD patients with motor fluctuations and compare them to a normative population and other PD populations. METHODS: All PD patients awaiting Deep Brain Stimulation (DBS) answered the TCI before neurosurgery. Their results were compared to those of historical cohorts (a French normative population, a de novo PD population, and a PD population with motor fluctuations). RESULTS: Most personality dimensions of our 333 included PD patients with motor fluctuations who are candidates for DBS were different from those of the normative population and some were also different from those of the De Novo PD population, whereas they were similar to those of another population of PD patients with motor fluctuations. CONCLUSIONS: During the course of PD, personality dimensions can change in parallel with the development of motor fluctuations, either due to the evolution of the disease and/or dopaminergic treatments.

Antisaccade, a predictive marker for freezing of gait in Parkinson's disease and gait/gaze network connectivity.

Freezing of gait is a challenging sign of Parkinson's disease associated with disease severity and progression and involving the mesencephalic locomotor region. No predictive factor of freezing has been reported so far. The primary objective of this study was to identify predictors of freezing occurrence at 5 years. In addition, we tested whether functional connectivity of the mesencephalic locomotor region could explain the oculomotor factors at baseline that were predictive of freezing onset. We performed a prospective study investigating markers (parkinsonian signs, cognitive status and oculomotor recordings, with a particular focus on the antisaccade latencies) of disease progression at baseline and at 5 years. We identified two groups of patients defined by the onset of freezing at 5 years of follow-up; the 'Freezer' group was defined by the onset of freezing in the ON medication condition during follow-up (n = 17), while the 'non-Freezer' group did not (n = 8). Whole brain resting-state functional MRI was recorded at baseline to determine how antisaccade latencies were associated with connectivity of the mesencephalic locomotor region networks in patients compared to 25 age-matched healthy volunteers. Results showed that, at baseline and compared to the non-Freezer group, the Freezer group had equivalent motor or cognitive signs, but increased antisaccade latencies (P = 0.008). The 5-year course of freezing of gait was correlated with worsening antisaccade latencies (P = 0.0007). Baseline antisaccade latencies was also predictive of the freezing onset (χ2 = 0.008). Resting state connectivity of mesencephalic locomotor region networks correlated with (i) antisaccade latency differently in patients and healthy volunteers at baseline; and (ii) the further increase of antisaccade latency at 5 years. We concluded that antisaccade latency is a predictive marker of the 5-year onset of freezing of gait. Our study suggests that functional networks associated with gait and gaze control are concurrently altered during the course of the disease.

Whispering dysphonia in TUBB4A-related disorders responsive to bipallidal deep brain stimulation.

BACKGROUND: Mutations in TUBB4A are associated with a wide phenotypic spectrum including generalized dystonia with whispering dysphonia (DYT-TUBB4A). METHODS: We report the case of a 44-year-old patient with DYT-TUBB4A with a clinical presentation of disabling progressive dystonia, with a prominent laryngeal, cervical and facial involvement. RESULTS: Bipallidal deep brain stimulation (DBS) resulted in a 55% reduction of dystonia severity assessed by the Burke-Fahn-Marsden scale score 6 months after surgery. The effect was obvious on the cervical and facial components of dystonia. CONCLUSION: We suggest that bipallidal DBS should be considered in patients with disabling dystonia related to TUBB4A variants.

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.

Personality Dimensions Are Associated with Quality of Life in Fluctuating Parkinson's Disease Patients (PSYCHO-STIM).

BACKGROUND: Parkinson's disease (PD) negatively affects patients' Quality of Life (QoL) which depends on both objective criteria such as physical health and subjective ones such as worries and norms according to personal believes. Therefore, QoL could be also associated to personality dimensions in chronic neurological diseases such as PD. OBJECTIVE: Our objective was thus to study the potential association between personality dimensions and QoL in PD patients with motor fluctuations before Deep Brain Stimulation of the Sub-Thalamic Nucleus (DBS-STN). METHODS: Data were obtained from the French multicentric cohort study Predi-Stim. All PD patients awaiting DBS-STN and responding to the inclusion criteria at the time of the study were included. All participants answered the "Temperament and Character Inventory" (TCI) and the PDQ-39 before surgery. Analyses were made using adjusted univariate generalized linear regression models to evaluate a potential association between TCI dimensions and PDQ-39 scores. RESULTS: Three hundred thirty-three consecutive patients were included. The temperament Harm Avoidance was negatively associated with QoL (p = 1e-4, R2= 0.33), whereas the character Self-Directedness was positively associated with mental component of QoL (p = 2e-4, R2= 0.33) in PD patients with motor fluctuations awaiting DBS-STN. CONCLUSIONS: PD patients with motor fluctuations, with lower Harm Avoidance and higher Self-Directedness scores have the best QoL mainly at an emotional and social level. Therapeutic education of these PD patients focusing on their personal resources may thus be important to improve their well-being.