A General Neurologist's Practical Diagnostic Algorithm for Atypical Parkinsonian Disorders: A Consensus Statement.

Purpose of Review: The most common four neurodegenerative atypical parkinsonian disorders (APDs) are progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal syndrome (CBS), and dementia with Lewy bodies (DLB). Their formal diagnostic criteria often require subspecialty experience to implement as designed and all require excluding competing diagnoses without clearly specifying how to do that. Validated diagnostic criteria are not available at all for many of the other common APDs, including normal pressure hydrocephalus (NPH), vascular parkinsonism (VP), or drug-induced parkinsonism (DIP). APDs also include conditions of structural, genetic, vascular, toxic/metabolic, infectious, and autoimmune origin. Their differential diagnosis can be challenging early in the course, if the presentation is atypical, or if a rare or non-neurodegenerative condition is present. This review equips community general neurologists to make an early provisional diagnosis before, or in place of, referral to a tertiary center. Early diagnosis would allay diagnostic uncertainty, allow prompt symptomatic management, provide disease-specific information and support resources, avoid further pointless testing and treatments, and create the possibility of trial referral. Recent Findings: We address 64 APDs using one over-arching flow diagram and a series of detailed tables. Most instances of APDs can be diagnosed with a careful history and neurological exam, along with a non-contrast brain MRI. Additional diagnostic tests are rarely needed but are delineated where applicable. Our diagnostic algorithm encourages referral to a tertiary center whenever the general neurologist feels it would be in the patient's best interest. Our algorithm emphasizes that the diagnosis of APDs is an iterative process, refined with the appearance of new diagnostic features, availability of new technology, and advances in scientific understanding of the disorders. Clinicians' proposals for all diagnostic tests for the APDs, including repeat visits, should be discussed with patients and their families to ensure that the potential information to be gained aligns with their larger clinical goals. Summary: We designed this differential diagnostic algorithm for the APDs to enhance general neurologists' diagnostic skills and confidence and to help them address the less common or more ambiguous cases.

Velocity-Based Training Affects Function, Strength, and Power in Persons with Parkinson's Disease.

ABSTRACT: Calaway, CC, Martinez, KJ, Calzada Bichili, AR, Caplan, JH, Milgrim, WP, Mann, JB, Haq, I, and Signorile, JF. Velocity-based training affects function, strength, and power in persons with Parkinson's disease. J Strength Cond Res XX(X): 000-000, 2024-Velocity-based training (VBT) is commonly associated with high-level athletes. No study has examined the effects of VBT on performance in persons with Parkinson's disease (PD). The objective of the study was to compare the effects of 10 and 30% velocity-loss threshold protocols on changes in functional performance, strength, and power in persons with PD after 12 weeks of supervised VBT, 3 days per week. Twenty-one subjects with PD (72.9 ± 5.9 y) were randomly assigned to the 10% or 30% velocity-loss threshold group and performed the 6-m walk test at habitual and maximal gait speed (6MWTMax), the 5 time sit-to-stand test (5 × STS), 1 repetition maximum (1RM), and peak power (PP) testing for the chest press (CP) and leg press (LP) exercise. A mixed ANOVA with significance was set a priori at 0.05 revealed that significant time effects were seen for the 6MWT at maximal speed (MDiff ± SD = 0.22 ± 0.04 m·s-1, p < 0.001), 5-time sit-to-stand time (-1.48 ± 0.45 seconds, p = 0.005) and power (75.5 ± 22.7 W, p = 0.005), 1RM for CP (5.1 ± 1.1 kg, p < 0.001) and LP (12.6 ± 3.7 kg, p = 0.005), and LP-PP (43.6 ± 13.2 W, p = 0.006). Secondary analyses revealed time effects for the load at which PP was achieved for the CP exercise. A Wilcoxon signed-rank test revealed no significant differences in the percentage of 1RM at which PP was achieved for either condition. Results indicate that VBT is an effective training modality for improving functional capacity, strength, and power in persons with PD; however, shifts in force-velocity relationships were not evidenced.

Subjective feelings associated with expectations and rewards during risky decision-making in impulse control disorder.

Impulse Control Disorder (ICD) in Parkinson's disease is a behavioral addiction induced by dopaminergic therapies, but otherwise unclear etiology. The current study investigates the interaction of reward processing variables, dopaminergic therapy, and risky decision-making and subjective feelings in patients with versus without ICD. Patients with (n = 18) and without (n = 12) ICD performed a risky decision-making task both 'on' and 'off' standard-of-care dopaminergic therapies (the task was performed on 2 different days with the order of on and off visits randomized for each patient). During each trial of the task, participants choose between two options, a gamble or a certain reward, and reported how they felt about decision outcomes. Subjective feelings of 'pleasure' are differentially driven by expectations of possible outcomes in patients with, versus without ICD. While off medication, the influence of expectations about risky-decisions on subjective feelings is reduced in patients with ICD versus without ICD. While on medication, the influence of expected outcomes in patients with ICD versus without ICD becomes similar. Computational modeling of behavior supports the idea that latent decision-making factors drive subjective feelings in patients with Parkinson's disease and that ICD status is associated with a change in the relationship between factors associated with risky behavior and subjective feelings about the experienced outcomes. Our results also suggest that dopaminergic medications modulate the impact expectations have on the participants' subjective reports. Altogether our results suggest that expectations about risky decisions may be decoupled from subjective feelings in patients with ICD, and that dopaminergic medications may reengage these circuits and increase emotional reactivity in patients with ICD.

Blepharoclonus in Parkinsonism.

Background and Objectives: In clinical practice, we have observed that patients with Parkinson disease (PD) often have blepharoclonus, but its prevalence is not well described in the literature. Understanding the relative frequencies of blepharoclonus in PD and atypical parkinsonian syndromes may shed light on the diagnostic utility of this clinical sign. We aimed to assess (1) the frequency of blepharoclonus in patients with PD in a single-center cohort; (2) the association of blepharoclonus with disease stage, tremor severity, and non-motor symptoms; and (3) the frequency of blepharoclonus in synucleinopathy vs non-synucleinopathy-associated parkinsonism. Methods: We prospectively enrolled 85 patients, 75 with PD and 10 with atypical parkinsonism. Blepharoclonus was considered present if eyelid fluttering was sustained for >5 seconds after gentle eye closure. For each patient, demographics were collected, and we completed selected questions from the MDS-UPDRS (Unified Parkinson's Disease Rating Scale) part 2, REM Sleep Behavior Disorder Questionnaire, and MDS-UPDRS part 3 tremor assessments and recorded the presence/absence of dyskinesia. Results: 63 of 75 patients with PD (84%) had blepharoclonus. Among the 10 patients with atypical parkinsonism, 5 had synucleinopathy syndromes. Blepharoclonus was present in 3 of 5 patients with synucleinopathy and 0 of 5 patients with non-synucleinopathy-associated parkinsonian syndromes. Discussion: Blepharoclonus is prevalent in our PD cohort, suggesting possible utility as a clinical marker for PD. The absence of blepharoclonus in a patient with parkinsonism may suggest a non-synucleinopathy (e.g., tauopathy). Analysis of a larger cohort of both PD and atypical parkinsonism would be needed to establish whether blepharoclonus distinguishes PD from atypical parkinsonism, or synucleinopathy from non-synucleinopathy.

Sub-second Dopamine Signals during Risky Decision-Making in Patients with Impulse Control Disorder.

Background: Impulse Control Disorder (ICD) in Parkinson's disease is a behavioral addiction arising secondary to dopaminergic therapies, most often dopamine receptor agonists. Prior research implicates changes in striatal function and heightened dopaminergic activity in the dorsal striatum of patients with ICD. However, this prior work does not possess the temporal resolution required to investigate dopaminergic signaling during real-time progression through various stages of decision-making involving anticipation and feedback. Methods: We recorded high-frequency (10Hz) measurements of extracellular dopamine in the striatum of patients with (N=3) and without (N=3) a history of ICD secondary to dopamine receptor agonist therapy for Parkinson's disease symptoms. These measurements were made using carbon fiber microelectrodes during awake DBS neurosurgery and while participants performed a sequential decision-making task involving risky investment decisions and real monetary gains and losses. Per clinical standard-of-care, participants withheld all dopaminergic medications prior to the procedure. Results: Patients with ICD invested significantly more money than patients without ICD. On each trial, patients with ICD made smaller adjustments to their investment levels compared to patients without ICD. In patients with ICD, dopamine levels rose or fell on sub-second timescales in anticipation of investment outcomes consistent with increased or decreased confidence in a positive outcome, respectively; dopamine levels in patients without ICD were significantly more stable during this phase. After outcome revelation, dopamine levels in patients with ICD rose significantly more than in inpatients without ICD for better-than-expected gains. For worse-than-expected losses, dopamine levels in patients with ICD remained level whereas dopamine levels in patients without ICD fell. Conclusion: We report significantly increased risky behavior and exacerbated phasic dopamine signaling, on sub-second timescales, anticipating and following the revelation of the outcomes of risky decisions in patients with ICD. Notably, these results were obtained when patients who had demonstrated ICD in the past but were, at the time of surgery, in an off-medication state. Thus, it is unclear whether observed signals reflect an inherent predisposition for ICD that was revealed when dopamine receptor agonists were introduced or whether these observations were caused by the introduction of dopamine receptor agonists and the patients having experienced ICD symptoms in the past. Regardless, future work investigating dopamine's role in human cognition, behavior, and disease should consider the signals this system generates on sub-second timescales.

Time perception reflects individual differences in motor and non-motor symptoms of Parkinson's disease.

Decreasing dopaminergic function is at the core of Parkinson's disease (PD) motor symptoms and changes in dopaminergic action are associated with many comorbid non-motor symptoms in PD. Notably, dopaminergic signaling in the striatum has been shown to play a critical role in the perception of time. We hypothesize that patients with PD perceive time differently and in accordance with their specific comorbid non-motor symptoms and clinical state. This means that individual differences in clinical symptoms may be reflected in individual differences in timing behavior. To test this hypothesis, we recruited patients with PD and compared individual differences in patients' clinical state with their ability to judge intervals of time ranging from 500 ms to 1100 ms while on and off their prescribed dopaminergic medications. We show that medication state (on vs. off medications) did not affect timing behavior, but individual differences in timing behavior are able to predict individual differences in comorbid non-motor symptoms, duration of PD diagnosis, and prescribed dopaminergic medications. We show that comorbid impulse control disorder is associated with temporal overestimation; depression is associated with decreased temporal accuracy; and increased PD duration and prescribed levodopa monotherapy are associated with reduced temporal precision and accuracy. Observed differences in time perception are consistent with hypothesized dopaminergic mechanisms thought to underlie the respective motor and non-motor symptoms in PD. In future work, time perception tasks may augment clinical diagnosis strategies, or help disentangle the neural and cognitive mechanisms underlying PD motor and non-motor symptom etiology.

The vital role of natural history studies in rare disease: insights from X-linked dystonia parkinsonism.

This scientific commentary refers to 'Establishing a natural history of X-linked dystonia parkinsonism', by Acuna et al. (https://doi.org/10.1093/braincomms/fcad106).

Time perception reflects individual differences in motor and non-motor symptoms of Parkinson's disease.

Dopaminergic signaling in the striatum has been shown to play a critical role in the perception of time. Decreasing striatal dopamine efficacy is at the core of Parkinson's disease (PD) motor symptoms and changes in dopaminergic action have been associated with many comorbid non-motor symptoms in PD. We hypothesize that patients with PD perceive time differently and in accordance with their specific comorbid non-motor symptoms and clinical state. We recruited patients with PD and compared individual differences in patients' clinical features with their ability to judge millisecond to second intervals of time (500ms-1100ms) while on or off their prescribed dopaminergic medications. We show that individual differences in comorbid non-motor symptoms, PD duration, and prescribed dopaminergic pharmacotherapeutics account for individual differences in time perception performance. We report that comorbid impulse control disorder is associated with temporal overestimation; depression is associated with decreased temporal accuracy; and PD disease duration and prescribed levodopa monotherapy are associated with reduced temporal precision and accuracy. Observed differences in time perception are consistent with hypothesized dopaminergic mechanisms thought to underlie the respective motor and non-motor symptoms in PD, but also raise questions about specific dopaminergic mechanisms. In future work, time perception tasks like the one used here, may provide translational or reverse translational utility in investigations aimed at disentangling neural and cognitive systems underlying PD symptom etiology. One Sentence Summary: Quantitative characterization of time perception behavior reflects individual differences in Parkinson's disease motor and non-motor symptom clinical presentation that are consistent with hypothesized neural and cognitive mechanisms.

Interactive mobile application for Parkinson's disease deep brain stimulation (MAP DBS): An open-label, multicenter, randomized, controlled clinical trial.

INTRODUCTION: Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease (PD), but its efficacy is tied to DBS programming, which is often time consuming and burdensome for patients, caregivers, and clinicians. Our aim is to test whether the Mobile Application for PD DBS (MAP DBS), a clinical decision support system, can improve programming. METHODS: We conducted an open-label, 1:1 randomized, controlled, multicenter clinical trial comparing six months of SOC standard of care (SOC) to six months of MAP DBS-aided programming. We enrolled patients between 30 and 80 years old who received DBS to treat idiopathic PD at six expert centers across the United States. The primary outcome was time spent DBS programming and secondary outcomes measured changes in motor symptoms, caregiver strain and medication requirements. RESULTS: We found a significant reduction in initial visit time (SOC: 43.8 ± 28.9 min n = 37, MAP DBS: 27.4 ± 13.0 min n = 35, p = 0.001). We did not find a significant difference in total programming time between the groups over the 6-month study duration. MAP DBS-aided patients experienced a significantly larger reduction in UPDRS III on-medication scores (-7.0 ± 7.9) compared to SOC (-2.7 ± 6.9, p = 0.01) at six months. CONCLUSION: MAP DBS was well tolerated and improves key aspects of DBS programming time and clinical efficacy.

Intracranial subsecond dopamine measurements during a "sure bet or gamble" decision-making task in patients with alcohol use disorder suggest diminished dopaminergic signals about relief.

OBJECTIVE: To the authors' knowledge, no data have been reported on dopamine fluctuations on subsecond timescales in humans with alcohol use disorder (AUD). In this study, dopamine release was monitored in 2 patients with and 2 without a history of AUD during a "sure bet or gamble" (SBORG) decision-making task to begin to characterize how subsecond dopamine responses to counterfactual information, related to psychological notions of regret and relief, in AUD may be altered. METHODS: Measurements of extracellular dopamine levels were made once every 100 msec using human voltammetric methods. Measurements were made in the caudate during deep brain stimulation electrode implantation surgeries (for treatment of movement disorders) in patients who did (AUD, n = 2) or did not (non-AUD, n = 2) have a history of AUD. Participants performed an SBORG decision-making task in which they made choices between sure bets and 50%-chance monetary gamble outcomes. RESULTS: Fast changes were found in dopamine levels that appear to be modulated by "what could have been" and by patients' AUD status. Positive counterfactual prediction errors (related to relief) differentiated patients with versus without a history of AUD. CONCLUSIONS: Dopaminergic encoding of counterfactual information appears to differ between patients with and without AUD. The current study has a major limitation of a limited sample size, but these data provide a rare insight into dopaminergic physiology during real-time decision-making in humans with an addiction disorder. The authors hope future work will expand the sample size and determine the generalizability of the current results.

Rapid-onset dystonia-parkinsonism is associated with reduced cerebral blood flow without gray matter changes.

Purpose: Previous research showed discrete neuropathological changes associated with rapid-onset dystonia-parkinsonism (RDP) in brains from patients with an ATP1A3 variant, specifically in areas that mediate motor function. The purpose of this study was to determine if magnetic resonance imaging methodologies could identify differences between RDP patients and variant-negative controls in areas of the brain that mediate motor function in order to provide biomarkers for future treatment or prevention trials. Methods: Magnetic resonance imaging voxel-based morphometry and arterial spin labeling were used to measure gray matter volume and cerebral blood flow, respectively, in cortical motor areas, basal ganglia, thalamus, and cerebellum, in RDP patients with ATP1A3 variants (n = 19; mean age = 37 ± 14 years; 47% female) and variant-negative healthy controls (n = 11; mean age = 34 ± 19 years; 36% female). Results: We report age and sex-adjusted between group differences, with decreased cerebral blood flow among patients with ATP1A3 variants compared to variant-negative controls in the thalamus (p = 0.005, Bonferroni alpha level < 0.007 adjusted for regions). There were no statistically significant between-group differences for measures of gray matter volume. Conclusions: There is reduced cerebral blood flow within brain regions in patients with ATP1A3 variants within the thalamus. Additionally, the lack of corresponding gray matter volume differences may suggest an underlying functional etiology rather than structural abnormality.

Intracranial approach for sub-second monitoring of neurotransmitters during DBS electrode implantation does not increase infection rate.

INTRODUCTION: Currently, sub-second monitoring of neurotransmitter release in humans can only be performed during standard of care invasive procedures like DBS electrode implantation. The procedure requires acute insertion of a research probe and additional time in surgery, which may increase infection risk. We sought to determine the impact of our research procedure, particularly the extended time in surgery, on infection risk. METHODS: We screened 602 patients who had one or more procedure codes documented for DBS electrode implantation, generator placement, programming, or revision for any reason performed at Wake Forest Baptist Medical Center between January 2011 through October 2020 using International Classification of Diseases (ICD) codes for infection. During this period, 116 patients included an IRB approved 30-minute research protocol, during the Phase 1 DBS electrode implantation surgery, to monitor sub-second neurotransmitter release. We used Fisher's Exact test (FET) to determine if there was a significant change in the infection rate following DBS electrode implantation procedures that included, versus those that did not include, the neurotransmitter monitoring research protocol. RESULTS: Within 30-days following DBS electrode implantation, infection was observed in 1 (0.21%) out of 486 patients that did not participate in the research procedure and 2 (1.72%) of the 116 patients that did participate in the research procedure. Notably, all types of infection observed were typical of those expected for DBS electrode implantation. CONCLUSION: Infection rates are not statistically different across research and non-research groups within 30-days following the research procedure (1.72% vs. 0.21%; p = 0.0966, FET). Our results demonstrate that the research procedures used for sub-second monitoring of neurotransmitter release in humans can be performed without increasing the rate of infection.

Associations Between Vascular Risk Factors and Perivascular Spaces in Adults with Intact Cognition, Mild Cognitive Impairment, and Dementia.

BACKGROUND: Perivascular spaces (PVS) are fluid-filled compartments surrounding small intracerebral vessels that transport fluid and clear waste. OBJECTIVE: We examined associations between PVS count, vascular and neurodegenerative risk factors, and cognitive status among the predominantly Hispanic participants of the FL-VIP Study of Alzheimer's Disease Risk. METHODS: Using brain MRI (n = 228), we counted PVS in single axial image through the basal ganglia (BG) and centrum semiovale (CSO). PVS per region were scored as 0 (none), 1 (<10), 2 (11-20), 3 (21-40), and 4 (>40). Generalized linear models examined PVS associations with vascular risk factors and a composite vascular comorbidity risk (VASCom) score. RESULTS: Our sample (mean age 72±8 years, 61% women, 60% Hispanic, mean education 15±4 years, 33% APOE4 carriers) was 59% hypertensive, 21% diabetic, 66% hypercholesteremic, and 30% obese. Mean VASCom score was 2.3±1.6. PVS scores ranged from 0-4 in the BG (mean 1.3±0.7) and CSO (mean 1.2±0.9), and 0-7 combined (mean 2.5±1.4). In multivariable regression models, BG PVS was associated with age (ß= 0.03/year, p < 0.0001), Hispanic ethnicity (ß= 0.29, p = 0.01), education (ß= 0.04/year, p = 0.04), and coronary bypass surgery (ß= 0.93, p = 0.02). CSO PVS only associated with age (ß= 0.03/year, p < 0.01). APOE4 and amyloid-ß were not associated with PVS. CONCLUSION: BG PVS may be a marker of subclinical cerebrovascular disease. Further research is needed to validate associations and identify mechanisms linking BG PVS and cerebrovascular disease markers. PVS may be a marker of neurodegeneration despite our negative preliminary findings and more research is warranted. The association between BG PVS and Hispanic ethnicity also requires further investigation.

COVID-19 and Vaccination in the Setting of Neurologic Disease: An Emerging Issue in Neurology.

The COVID-19 pandemic caused by the SARS-CoV-2 virus has left many unanswered questions for patients with neurological disorders and the providers caring for them. Elderly and immunocompromised patients are at increased risk for severe symptoms due to COVID-19, and the virus may increase symptoms of underlying neurological illness, particularly for those with significant bulbar and respiratory weakness or other neurologic disability. Emerging SARS-CoV-2 vaccines offer substantial protection from symptomatic infection, but both patients and providers may have concerns regarding theoretical risks of vaccination, including vaccine safety and efficacy in the context of immunotherapy and the potential for precipitating or exacerbating neurological symptoms. In this statement on behalf of the Quality Committee of the AAN we review the current literature, focusing on COVID-19 infection in adults with neurological disease, in order to elucidate risks and benefits of vaccination in these individuals. Based on existing evidence, neurologists should recommend COVID-19 vaccination to their patients. For those patients being treated with immunotherapies, attention should be paid to timing of vaccination with respect to treatment and the potential for an attenuated immune response.

MR Tractography-Based Targeting and Physiological Identification of the Cuneiform Nucleus for Directional DBS in a Parkinson's Disease Patient With Levodopa-Resistant Freezing of Gait.

BACKGROUND: Freezing of gait (FOG) is a debilitating motor deficit in a subset of Parkinson's Disease (PD) patients that is poorly responsive to levodopa or deep brain stimulation (DBS) of established PD targets. The proposal of a DBS target in the midbrain, known as the pedunculopontine nucleus (PPN), to address FOG was based on its observed neuropathology in PD and its hypothesized involvement in locomotor control as a part of the mesencephalic locomotor region (MLR). Initial reports of PPN DBS were met with enthusiasm; however, subsequent studies reported mixed results. A closer review of the MLR basic science literature, suggests that the closely related cuneiform nucleus (CnF), dorsal to the PPN, may be a superior site to promote gait. Although suspected to have a conserved role in the control of gait in humans, deliberate stimulation of a homolog to the CnF in humans using directional DBS electrodes has not been attempted. METHODS: As part of an open-label Phase 1 clinical study, one PD patient with predominantly axial symptoms and severe FOG refractory to levodopa therapy was implanted with directional DBS electrodes (Boston Science Vercise CartesiaTM) targeting the CnF bilaterally. Since the CnF is a poorly defined reticular nucleus, targeting was guided both by diffusion tensor imaging (DTI) tractography and anatomical landmarks. Intraoperative stimulation and microelectrode recordings were performed near the targets with leg EMG surface recordings in the subject. RESULTS: Post-operative imaging revealed accurate targeting of both leads to the designated CnF. Intraoperative stimulation near the target at low thresholds in the awake patient evoked involuntary electromyography (EMG) oscillations in the legs with a peak power at the stimulation frequency, similar to observations with CnF DBS in animals. Oscillopsia was the primary side effect evoked at higher currents, especially when directed posterolaterally. Directional DBS could mitigate oscillopsia. CONCLUSION: DTI-based targeting and intraoperative stimulation to evoke limb EMG activity may be useful methods to help target the CnF accurately and safely in patients. Long term follow-up and detailed gait testing of patients undergoing CnF stimulation will be necessary to confirm the effects on FOG. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT04218526.

Deep brain stimulation of the Cuneiform nucleus for levodopa-resistant freezing of gait in Parkinson's disease: study protocol for a prospective, pilot trial.

BACKGROUND: Freezing of gait (FOG) is a particularly debilitating motor deficit seen in a subset of Parkinson's disease (PD) patients that is poorly responsive to standard levodopa therapy or deep brain stimulation (DBS) of established PD targets such as the subthalamic nucleus and the globus pallidus interna. The proposal of a DBS target in the midbrain, known as the pedunculopontine nucleus (PPN) to address FOG, was based on its observed pathology in PD and its hypothesized involvement in locomotor control as a part of the mesencephalic locomotor region, a functionally defined area of the midbrain that elicits locomotion in both intact animals and decerebrate animal preparations with electrical stimulation. Initial reports of PPN DBS were met with much enthusiasm; however, subsequent studies produced mixed results, and recent meta-analysis results have been far less convincing than initially expected. A closer review of the extensive mesencephalic locomotor region (MLR) preclinical literature, including recent optogenetics studies, strongly suggests that the closely related cuneiform nucleus (CnF), just dorsal to the PPN, may be a superior target to promote gait initiation. METHODS: We will conduct a prospective, open-label, single-arm pilot study to assess safety and feasibility of CnF DBS in PD patients with levodopa-refractory FOG. Four patients will receive CnF DBS and have gait assessments with and without DBS during a 6-month follow-up. DISCUSSION: This paper presents the study design and rationale for a pilot study investigating a novel DBS target for gait dysfunction, including targeting considerations. This pilot study is intended to support future larger scale clinical trials investigating this target. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04218526 (registered January 6, 2020).

Auditory-perceptual voice and speech evaluation in ATP1A3 positive patients.

INTRODUCTION: Bulbar symptoms are frequent in patients with rapid-onset dystonia-parkinsonism (RDP). RDP is caused by ATP1A3 mutations, with onset typically within 30 days of stressor exposure. Most patients have impairments in speech (dysarthria) and voice (dysphonia). These have not been quantified. We aimed to formally characterize these in RDP subjects as compared to mutation negative family controls. METHODS: We analyzed recordings in 32 RDP subjects (male = 21, female = 11) and 29 mutation negative controls (male = 15, female = 14). Three raters, blinded to mutation status, rated speech and vocal quality. Dysarthria was classified by subtype. Dysphonia was rated via the GRBAS (Grade, Roughness, Breathiness, Asthenia, Strain) scale. We used general neurological exams and the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) to assess dysarthria, dystonia, and speech/swallowing dysfunction. RESULTS: The presence of dysarthria was more frequent in RDP subjects compared to controls (72% vs. 17%, p < 0.0001). GRBAS voice ratings were worse in the RDP cohort across nearly all categories. Dysarthria in RDP was associated with concordant cranial nerve 9-11 dysfunction (54%, p = 0.048), speech/swallowing dysfunction (96%, p = 0.0003); and oral dystonia (88%, p = 0.001). CONCLUSIONS: Quantitative voice and speech analyses are important in assessing RDP. Subjects frequently experience dysarthria and dysphonia. Dystonia is not the exclusive voice abnormality present in this population. In our analysis, RDP subjects more frequently experienced bulbar symptoms than controls. GRBAS scores are useful in quantifying voice impairment, potentially allowing for better assessments of progression or treatment effects. Future directions include using task-specific diagnostic and perceptual voice evaluation tools to further assess laryngeal dystonia.