Disentangling Bradykinesia and Rigidity in Parkinson's Disease: Evidence from Short- and Long-Term Subthalamic Nucleus Deep Brain Stimulation.

OBJECTIVE: Bradykinesia and rigidity are considered closely related motor signs in Parkinson disease (PD), but recent neurophysiological findings suggest distinct pathophysiological mechanisms. This study aims to examine and compare longitudinal changes in bradykinesia and rigidity in PD patients treated with bilateral subthalamic nucleus deep brain stimulation (STN-DBS). METHODS: In this retrospective cohort study, the clinical progression of appendicular and axial bradykinesia and rigidity was assessed up to 15 years after STN-DBS in the best treatment conditions (ON medication and ON stimulation). The severity of bradykinesia and rigidity was examined using ad hoc composite scores from specific subitems of the Unified Parkinson's Disease Rating Scale motor part (UPDRS-III). Short- and long-term predictors of bradykinesia and rigidity were analyzed through linear regression analysis, considering various preoperative demographic and clinical data, including disease duration and severity, phenotype, motor and cognitive scores (eg, frontal score), and medication. RESULTS: A total of 301 patients were examined before and 1 year after surgery. Among them, 101 and 56 individuals were also evaluated at 10-year and 15-year follow-ups, respectively. Bradykinesia significantly worsened after surgery, especially in appendicular segments (p < 0.001). Conversely, rigidity showed sustained benefit, with unchanged clinical scores compared to preoperative assessment (p > 0.05). Preoperative motor disability (eg, composite scores from the UPDRS-III) predicted short- and long-term outcomes for both bradykinesia and rigidity (p < 0.01). Executive dysfunction was specifically linked to bradykinesia but not to rigidity (p < 0.05). INTERPRETATION: Bradykinesia and rigidity show long-term divergent progression in PD following STN-DBS and are associated with independent clinical factors, supporting the hypothesis of partially distinct pathophysiology. ANN NEUROL 2024;96:234-246.

Long-term effects of bilateral subthalamic nucleus deep brain stimulation on gait disorders in Parkinson's disease: a clinical-instrumental study.

OBJECTIVE: To assess the long-term effects of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) on gait in a cohort of advanced Parkinson's Disease (PD) patients. METHODS: This observational study included consecutive PD patients treated with bilateral STN-DBS. Different stimulation and drug treatment conditions were assessed: on-stimulation/off-medication, off-stimulation/off-medication, and on-stimulation/on-medication. Each patient performed the instrumented Timed Up and Go test (iTUG). The instrumental evaluation of walking ability was carried out with a wearable inertial sensor containing a three-dimensional (3D) accelerometer, gyroscope, and magnetometer. This device could provide 3D linear acceleration, angular velocity, and magnetic field vector. Disease motor severity was evaluated with the total score and subscores of the Unified Parkinson Disease Rating Scale part III. RESULTS: Twenty-five PD patients with a 5-years median follow-up after surgery (range 3-7) were included (18 men; mean disease duration at surgery 10.44 ± 4.62 years; mean age at surgery 58.40 ± 5.73 years). Both stimulation and medication reduced the total duration of the iTUG and most of its different phases, suggesting a long-term beneficial effect on gait after surgery. However, comparing the two treatments, dopaminergic therapy had a more marked effect in all test phases. STN-DBS alone reduced total iTUG duration, sit-to-stand, and second turn phases duration, while it had a lower effect on stand-to-sit, first turn, forward walking, and walking backward phases duration. CONCLUSIONS: This study highlighted that in the long-term after surgery, STN-DBS may contribute to gait and postural control improvement when used together with dopamine replacement therapy, which still shows a substantial beneficial effect.

Interplay between speech and gait variables in Parkinson's disease patients treated with subthalamic nucleus deep brain stimulation: A long-term instrumental assessment.

OBJECTIVE: To evaluate correlations between speech and gait parameters in the long term and under different medication and subthalamic nucleus deep brain stimulation (STN-DBS) conditions in a cohort of advanced Parkinson's disease (PD) patients. METHODS: This observational study included consecutive PD patients treated with bilateral STN-DBS. Axial symptoms were evaluated using a standardized clinical-instrumental approach. Speech and gait were assessed by perceptual and acoustic analyses and by the instrumented Timed Up and Go (iTUG) test, respectively. Disease motor severity was evaluated with the total score and subscores of the Unified Parkinson's Disease Rating Scale (UPDRS) Part III. Different stimulation and drug treatment conditions were assessed: on-stimulation/off-medication, off-stimulation/off-medication, and on-stimulation/on-medication. RESULTS: Twenty-five PD patients with a 5-year median follow-up after surgery (range 3-7 years) were included (18 males; disease duration at surgery: 10.44 [SD 4.62] years; age at surgery: 58.40 [SD 5.73] years). In the off-stimulation/off-medication and on-stimulation/on-medication conditions, patients who spoke louder had also the greater acceleration of the trunk during gait; whereas in the on-stimulation/on-medication condition only, patients with the poorer voice quality were also the worst to perform the sit to stand and gait phases of the iTUG. Conversely, patients with the higher speech rate performed well in the turning and walking phases of the iTUG. CONCLUSIONS: This study underlines the presence of different correlations between treatment effects of speech and gait parameters in PD patients treated with bilateral STN-DBS. This may allow us to better understand the common pathophysiological basis of these alterations and to develop a more specific and tailored rehabilitation approach for axial signs after surgery.

Axial impairment and falls in Parkinson's disease: 15 years of subthalamic deep brain stimulation.

In this retrospective study, we longitudinally analyzed axial impairment and falls in people with Parkinson's disease (PD) and subthalamic nucleus deep brain stimulation (STN-DBS). Axial scores and falling frequency were examined at baseline, and 1, 10, and 15 years after surgery. Preoperative demographic and clinical data, including PD duration and severity, phenotype, motor and cognitive scales, medications, and vascular changes on neuroimaging were examined as possible risk factors through Kaplan-Meier and Cox regression analyses. Of 302 individuals examined before and at 1 year after surgery, 102 and 57 were available also at 10 and 15 years of follow-up, respectively. Axial scores were similar at baseline and at 1 year but worsened at 10 and 15 years. The prevalence rate of frequent fallers progressively increased from baseline to 15 years. Preoperative axial scores, frontal dysfunction and age at PD onset were risk factors for axial impairment progression after surgery. Axial scores, akinetic/rigid phenotype, age at disease onset and disease duration at surgery predicted frequent falls. Overall, axial signs progressively worsened over the long-term period following STN-DBS, likely related to the progression of PD, especially in a subgroup of subjects with specific risk factors.

Does Motor Symptoms Asymmetry Predict Motor Outcome of Subthalamic Deep Brain Stimulation in Parkinson's Disease Patients?

Background: In Parkinson's disease (PD), the side of motor symptoms onset may influence disease progression, with a faster motor symptom progression in patients with left side lateralization. Moreover, worse neuropsychological outcomes after subthalamic nucleus deep brain stimulation (STN-DBS) have been described in patients with predominantly left-sided motor symptoms. The objective of this study was to evaluate if the body side of motor symptoms onset may predict motor outcome of bilateral STN-DBS. Methods: This retrospective study included all consecutive PD patients treated with bilateral STN-DBS at Grenoble University Hospital from 1993 to 2015. Demographic, clinical and neuroimaging data were collected before (baseline condition) and 1 year after surgery (follow-up condition). The predictive factors of motor outcome at one-year follow-up, measured by the percentage change in the MDS-UPDRS-III score, were evaluated through univariate and multivariate linear regression analysis. Results: A total of 233 patients were included with one-year follow-up after surgery [143 males (61.40%); 121 (51.90 %) right body onset; 112 (48.10%) left body onset; mean age at surgery, 55.31 ± 8.44 years; mean disease duration, 11.61 ± 3.87]. Multivariate linear regression analysis showed that the left side of motor symptoms onset did not predict motor outcome (ß = 0.093, 95% CI = -1.967 to 11.497, p = 0.164). Conclusions: In this retrospective study, the body side of motor symptoms onset did not significantly influence the one-year motor outcome in a large cohort of PD patients treated with bilateral STN-DBS.

Long-term independence and quality of life after subthalamic stimulation in Parkinson disease.

BACKGROUND AND PURPOSE: Studies on long-term nonmotor outcomes of subthalamic nucleus stimulation in Parkinson disease (PD) are scarce. This study reports on very long-term non-motor and motor outcomes in one of the largest cohorts of people with advanced PD, treated for >10 years with subthalamic nucleus stimulation. The main outcome was to document the evolution of independence in activities of daily living. The secondary outcomes were to measure the change in quality of life, as well as non-motor and motor outcomes. METHODS: Patients were studied preoperatively, at 1 year, and beyond 10 years after subthalamic stimulation with an established protocol including motor, non-motor, and neuropsychological assessments. RESULTS: Eighty-five people with PD were included. Independence scores in the off-medication condition (measured with the Schwab & England Activities of Daily Living Scale) as well as quality of life (measured with the Parkinson's Disease Questionnaire [PDQ]-37) remained improved at longest follow-up compared to preoperatively (respectively, p < 0.001, p = 0.015). Cognitive scores, measured with the Mattis Dementia Rating Scale, significantly worsened compared to before and 1 year after surgery (p < 0.001), without significant change in depression, measured with the Beck Depression Inventory. Motor fluctuations, dyskinesias, and off dystonia remained improved at longest follow-up (p < 0.001), with a significant reduction in dopaminergic treatment (45%, p < 0.001). CONCLUSIONS: This study highlights the long-term improvement of subthalamic stimulation on independence and quality of life, despite the progression of disease and the occurrence of levodopa-resistant symptoms.

Short- and long-term outcome and predictors in an international cohort of patients with neuro-COVID-19.

BACKGROUND AND PURPOSE: Despite the increasing number of reports on the spectrum of neurological manifestations of COVID-19 (neuro-COVID), few studies have assessed short- and long-term outcome of the disease. METHODS: This is a cohort study enrolling adult patients with neuro-COVID seen in neurological consultation. Data were collected prospectively or retrospectively in the European Academy of Neurology NEuro-covid ReGistrY ((ENERGY). The outcome at discharge was measured using the modified Rankin Scale and defined as 'stable/improved' if the modified Rankin Scale score was equal to or lower than the pre-morbid score, 'worse' if the score was higher than the pre-morbid score. Status at 6 months was also recorded. Demographic and clinical variables were assessed as predictors of outcome at discharge and 6 months. RESULTS: From July 2020 to March 2021, 971 patients from 19 countries were included. 810 (83.4%) were hospitalized. 432 (53.3%) were discharged with worse functional status. Older age, stupor/coma, stroke and intensive care unit (ICU) admission were predictors of worse outcome at discharge. 132 (16.3%) died in hospital. Older age, cancer, cardiovascular complications, refractory shock, stupor/coma and ICU admission were associated with death. 262 were followed for 6 months. Acute stroke or ataxia, ICU admission and degree of functional impairment at discharge were predictors of worse outcome. 65/221 hospitalized patients (29.4%) and 10/32 non-hospitalized patients (24.4%) experienced persisting neurological symptoms/signs. 10/262 patients (3.8%) developed new neurological complaints during the 6 months of follow-up. CONCLUSIONS: Neuro-COVID is a severe disease associated with worse functional status at discharge, particularly in older subjects and those with comorbidities and acute complications of infection.

Long-term Outcomes (15 Years) After Subthalamic Nucleus Deep Brain Stimulation in Patients With Parkinson Disease.

OBJECTIVE: To evaluate the effects of deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson disease (PD) patients on motor complications beyond 15 years after surgery. METHODS: Data about motor complications, quality of life (QoL), activities of daily living, the UPDRS motor scores, dopaminergic treatment, stimulation parameters, and side effects of STN-DBS were retrospectively retrieved and compared between before surgery, at 1 year and beyond 15 years after bilateral STN-DBS. RESULTS: Fifty-one patients with 17.06 ± 2.18 years STN-DBS follow-up were recruited. Compared to baseline, the time spent with dyskinesia and the time spent in the off state were reduced by 75% (p<0.001) and by 58.7% (p<0.001), respectively. Moreover, dopaminergic drugs were reduced by 50.6% (p<0.001). The PDQL total score, and the emotional function and social function domains improved of 13.8% (p=0.005), 13.6% (p=0.01) and 29.9% (p<0.001), respectively. Few and mostly manageable device-related adverse events were observed during the follow-up. CONCLUSIONS: STN-DBS is still effective beyond 15 years from the intervention, notably with significant improvement in motor complications and stable reduction of dopaminergic drugs. Furthermore, despite the natural continuous progression of PD with worsening of levodopa-resistant motor and non-motor symptoms over the years, STN-DBS patients could maintain an improvement in QoL. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that, for patients with PD, STN-DBS remains effective at treating motor complications 15 years after surgery.

Predictors of Long-Term Outcome of Subthalamic Stimulation in Parkinson Disease.

OBJECTIVE: This study was undertaken to identify preoperative predictive factors of long-term motor outcome in a large cohort of consecutive Parkinson disease (PD) patients with bilateral subthalamic nucleus deep brain stimulation (STN-DBS). METHODS: All consecutive PD patients who underwent bilateral STN-DBS at the Grenoble University Hospital (France) from 1993 to 2015 were evaluated before surgery, at 1 year (short-term), and in the long term after surgery. All available demographic variables, neuroimaging data, and clinical characteristics were collected. Preoperative predictors of long-term motor outcome were investigated by performing survival and univariate/multivariate Cox regression analyses. Loss of motor benefit from stimulation in the long term was defined as a reduction of less than 25% in the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III scores compared to the baseline off-medication scores. As a secondary objective, potential predictors of short-term motor outcome after STN-DBS were assessed by performing univariate and multivariate linear regression analyses. RESULTS: In the long-term analyses (mean follow-up = 8.4 ± 6.26 years, median = 10 years, range = 1-17 years), 138 patients were included. Preoperative higher frontal score and off-medication MDS-UPDRS part III scores predicted a better long-term motor response to stimulation, whereas the presence of vascular changes on neuroimaging predicted a worse motor outcome. In 357 patients with available 1-year follow-up, preoperative levodopa response, tremor dominant phenotype, baseline frontal score, and off-medication MDS-UPDRS part III scores predicted the short-term motor outcome. INTERPRETATION: Frontal lobe dysfunction, disease severity in the off-medication condition, and the presence of vascular changes on neuroimaging represent the main preoperative clinical predictors of long-term motor STN-DBS effects. ANN NEUROL 2021;89:587-597.

Dyspnea after subthalamic deep brain stimulation in Parkinson's disease: a case-control study.

OBJECTIVE: Dyspnea can be present as non-motor symptom in patients with Parkinson's disease (PD). Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves motor and non-motor symptoms in PD. However, new-onset dyspnea has been reported after DBS surgery. We have studied respiratory characteristics of PD patients with bilateral STN-DBS to assess the impact of DBS on pulmonary function. METHODS: STN-DBS PD patients with dyspnea after surgery (cases) were matched with STN-DBS PD patients without dyspnea (controls). Motor and pulmonary function were assessed with stimulation and without medication (on stim/off med), and without stimulation and medication (off stim/off med). Pulmonary function was investigated with spirometry and dyspnea with the Medical Research Council Dyspnea Scale (MRCDS) and the Borg Scale (BS). RESULTS: Seven cases (five men, 58.30 ± 6.70 years of age) and seven controls (six men, 61.10 ± 6.30 years of age) were enrolled. MRCDS and BS revealed the presence of dyspnea in both groups. No significant changes in pulmonary function were found in both cases and controls in on stim/off med vs. off stim/off med condition (p < 0.05), and in cases vs. controls in on stim/ off med condition (p < 0.05). CONCLUSIONS: No impact of STN-DBS on pulmonary function was found in cases. Impaired perception of dyspnea and spread of stimulation surrounding the STN might account for new-onset dyspnea after DBS surgery. Dyspnea was detected also in controls using ad hoc questionnaires. Our findings suggest further investigation of this non-motor symptom in PD patients.

Long-term neuropsychiatric outcomes after pallidal stimulation in primary and secondary dystonia.

OBJECTIVE: To evaluate changes in the diagnosis of Axis I psychiatric disorders in patients with primary and secondary dystonia after deep brain stimulation (DBS) of the globus pallidus internus (GPi). METHODS: Structured Clinical Interviews for the DSM-IV, Axis I psychiatric disorders, were prospectively performed before and after surgery. Diagnoses were made based on DSM-IV criteria. Psychiatric disorders were grouped into 5 categories: mood, anxiety, addiction, obsessive-compulsive disorders, and psychosis. Patients could be stratified to more than one category. Rates for unchanged diagnoses, diagnoses in remission, and new-onset diagnoses after surgery for each category were calculated. RESULTS: Fifty-seven patients with primary and secondary dystonia were included. Mean ± SD age at surgery and dystonia duration at time of surgery was 50.6 ± 13.8 and 19.0 ± 13.2 years, respectively. Preoperatively, 37 Axis I diagnoses were made in 25 patients, 43.8% of those presenting with at least 1 Axis I diagnosis (mostly mood and anxiety disorders). Mean ± SD duration of psychiatric follow-up was 24.4 ± 19.6 months. Overall, after surgery no significant changes (p = 0.16) were found in Axis I diagnoses (23 patients, 40.3%): 27 (73%) unchanged, 10 (27%) in complete remission, and 4 (12.9%) new-onset diagnoses. CONCLUSIONS: Our results support the overall psychiatric stability of patients with primary and secondary dystonia treated with GPi DBS. However, considering the high psychiatric morbidity in the dystonia population, psychiatric assessments before and after surgery are strongly recommended. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that GPi DBS does not change Axis I psychiatric diagnoses in patients with primary and secondary dystonia.