Gait & Posture

BACKGROUND: Dual task walking requires simultaneous management of cognitive and motor demands and is associated with changes in gait and cortical activation. However, the relationship between task related cortical recruitment and dual task related gait adjustments in healthy young adults remains unclear. This study aimed to investigate the effects of dual tasking on gait performance and cortical activation, and to examine the association between changes in cortical activity and dual-task costs. METHODS: This cross sectional study included 33 healthy young adults. Participants performed three conditions: single task walking, cognitive single task (verbal fluency), and dual task walking. Each condition was repeated 10 times using a repeated short block design with randomized trial presentation. Gait performance was assessed using an instrumented walkway, and cortical activation was measured using functional near infrared spectroscopy. Dual task costs were calculated for gait and cognitive outcomes. Statistical analysis included repeated measures analysis of variance (ANOVA) and Wilcoxon signed rank tests, with false discovery rate correction for multiple comparisons. Associations between changes in cortical activation and dual task costs were examined using correlation analyses. RESULTS: Dual task walking resulted in significant changes in gait, including reduced speed, step and stride length, and increased base of support, stance, and double support (all p < 0.05), while cognitive performance remained unchanged. Dual tasking was associated with increased cortical activation in left prefrontal and motor related regions. Greater increases in cortical activation were associated with lower dual task costs across most gait parameters, with significant correlations observed in the left dorsolateral prefrontal cortex (r {approx} 0.42 to 0.47 for speed and stride length; p < 0.05). Double support showed a distinct pattern, suggesting a specific temporal adjustment within the gait cycle. CONCLUSIONS: Dual task walking in young adults is associated with coordinated behavioral and cortical adaptations. Increased cortical recruitment is linked to reduced motor interference, suggesting that broader engagement of cortical networks may contribute to performance under cognitive motor load.

Freezing of gait is a disabling episodic symptom of Parkinson's disease, typically emerging during complex locomotor tasks such as turning, obstacle negotiation, and gait initiation. These tasks require effective motor planning and proactive visual search of the intended walking route. Current evidence suggests that people with Parkinson's disease and freezing of gait show different patterns of visual search compared to those without freezing of gait and healthy older adults. However, existing reports are based on relatively simple tasks that lack common triggers for freezing of gait and do not adequately control for other factors likely to influence visual search, such as motor symptom severity and balance ability. This study examined visual search behaviour in 24 healthy older adults and 37 people with Parkinson's disease (21 with freezing of gait, 16 without) during a complex walking task requiring repeated turning and navigation through narrow spaces. Visual search characteristics were compared between people with Parkinson's disease and healthy controls, and relationships between visual search, freezing of gait, motor symptom severity, and balance ability were explored within the Parkinson's disease group. Compared with healthy controls, people with Parkinson's disease showed significantly fewer fixations toward areas outside the walking path, longer average fixation durations, and reduced saccade amplitudes, with no differences in proactive visual planning of the intended route. No relationship was found between visual search outcomes and freezing of gait. Reduced fixations to outside-path areas were associated with poorer functional balance independently of motor symptom severity. These findings indicate that restricted visual sampling in Parkinson's disease is primarily associated with balance impairment rather than freezing of gait or motor symptom severity.

Background and Objectives Patients with peripheral neuropathies (PN) commonly exhibit balance impairment. In clinical practice, balance is typically assessed using the Rombergs test and ataxia scales, which rely on examiner interpretation, while objective biomarkers for quantifying balance remain lacking. Wearable sensors are valuable tools for objectively quantifying gait abnormalities in PN patients and may capture clinically meaningful changes over time. By integrating these parameters, artificial intelligence (AI) can assist in generating a digital score that enables easy, objective, and reproducible monitoring of patients postural balance. This study aims to generate and assess an AI-generated digital Rombergs test to quantify balance impairments in a cohort of PN patients. Methods PN patients were assessed in a longitudinal study using a wearable system composed of inertial sensors placed on the trunk and plantar pressure sensors integrated in insoles. Patients performed the Rombergs test under both eyes-open and eyes-closed conditions and were classified according to ataxia severity (mild, moderate, or severe) following the score obtained in item 1 of MICARS and SARA scales. Results We included 97 patients with PN (including autoimmune and hereditary polyneuropathies), and 117 healthy controls (HC). Significant differences in trunk sway and center of pressure (COP) were observed between groups, particularly with eyes closed. Using wearable sensor parameters, we developed an AI digital Rombergs test, which correlated with clinician-rated Rombergs test performance and distinguished patients with and without ataxia (AUC=0.632) and across different PN pathologies. Longitudinally, digital Rombergs test and iRODS showed concordant trajectories. Also, changes [&ge;]25% in the score were associated with clinical changes in ataxia severity measured by an increase in MICARS-SARA score (+1.42 points), whereas improvement was associated with a decrease (-0.20 points) in the scale. Discussion This study demonstrates that wearable sensors are useful to detect and quantify balance impairment. The AI-generated Rombergs test is an objective and reproducible tool for postural balance assessment, with robust discriminatory performance across clinical ataxia severity in PN. Scores longitudinal changes aligned with clinical severity, supporting its potential for monitoring disease progression and treatment response. Its strong association with balance measures reinforces its role as a quantitative biomarker of postural control in ataxia patients.

Uneven walking surfaces require adjustments in motor strategies and can thus provide insights into the neuromuscular changes underlying maturation. Also, coordination metrics and variability offer a richer description of motor control mechanisms than standard spatiotemporal parameters, constituting a more sensitive approach to characterize developmental changes. This study aimed to investigate the effects of uneven surfaces on intersegmental coordination, as well as inter-joint coordination and its variability, and to assess the differences in adaptation between age groups when walking on uneven surfaces. Seventy participants (2-29 years), divided into four age groups, completed gait trials on an even and two levels of uneven surfaces while equipped with reflective markers. Mean absolute relative phase and deviation phase of the knee-hip and ankle-knee joint pairs were computed to characterize lower limb inter-joint coordination and variability. In addition, the organization and density of whole-body intersegmental coordination were assessed using correlation networks built from marker acceleration data. Uneven surfaces induced more in-phase inter-joint coupling, reduced network density and increased variability across all age groups. While the organization of intersegmental coordination remained stable, older participants exhibited denser networks, reflecting refined segmental interactions. In contrast, younger participants showed more in-phase joint coordination and higher variability suggesting less mature motor control. The age-related inter-joint coordination differences were emphasized on uneven surfaces, likely reflecting the maturation-related ability to modulate spinal locomotor patterns via supraspinal control, thereby increasing adaptation to environmental perturbations. Highlights- Uneven surfaces induce more in-phase inter-joint coordination. - Uneven surfaces accentuate differences in locomotor strategies across development. - Kinectome density may be a promising indicator of locomotor maturation. - Coordinative variability decreased with neuromotor development.

Wearable exoskeletons are a promising tool for augmenting balance and reducing fall risk. Recent work suggests that active ankle exoskeletons need to act faster than the human to improve reactive balance control. However, the magnitude of exoskeleton torque that is best for improving reactive balance remains unknown. Drawing from the optimal torque for minimizing metabolic expenditure, we hypothesized that reactive balance would improve with increased exoskeleton torque. Participants wearing bilateral ankle exoskeletons were instructed to maintain standing balance during 15cm backward support-surface perturbations. Three exoskeleton plantarflexion torque conditions were tested: NO (Off), LOW (15Nm), or HIGH (30Nm). LOW torque improved balance performance compared to NO torque (p<0.001), with a 7{+/-}3% decrease in peak center of mass (CoM) displacement. Although HIGH torque caused a 9{+/-}11% decrease in peak CoM displacement compared to NO torque (p=0.12), it was not significant due to high intersubject variability. Whereas LOW torque decreased peak CoM displacement in all (range: -0.2 to -1.6cm), HIGH torque only decreased it in some (range = 1.2 to -2.6cm). The change in CoM displacement from LOW to HIGH torque was associated with balance ability, quantified by the narrowing beam test (R2=0.29, p=0.06), while this relationship didnt meet conventional statistical significance, likely due to the small sample size, it suggests that higher levels of exoskeleton torque may hinder balance performance in individuals with better balance ability. Taken together, more exoskeleton torque is not always better for balance, highlighting a potential need to personalize exoskeleton torque for balance augmentation.

Background: Huntington ' s disease (HD) causes progressive postural control deficits, but how sensory reweighting mechanisms degrade across disease stages remains poorly understood. Objective: To determine whether objective markers of postural sway track disease severity and altered sensory reweighting across the HD spectrum. Methods: Ninety-seven adults (46 {+/-} 14 yrs) were categorized into four groups: 29 with HD, 27 pre-manifest (PM), 28 not at risk (AR-), and 13 age-matched healthy controls (HC). Participants performed three trials of quiet standing with eyes open and eyes closed on a force plate. Results: Manifest HD individuals exhibited greater AP, ML, and total COP sway displacement compared with the PM, AR-, and HC groups. HD and PM groups demonstrated greater instability with eyes closed. COP wavelet power was concentrated below 1 Hz across all groups. The eyes-open to eyes-closed change in 0-1 Hz power predicted total COP sway in HC (68%), AR- (45%), and PM (46%), but this relation was substantially weaker in HD. Conclusions: Progressive weakening of oscillatory-sway coupling distinguishes manifest HD from premanifest stages. PM individuals demonstrate early sensory reweighting deficits that manifest only when vision is removed, while HD individuals show decoupled oscillatory activity that fails to support stable postural regulation. This progressive decoupling may serve as a candidate marker of disease conversion prior to overt motor diagnosis.

Gait asymmetry is a common manifestation of walking impairment among clinical populations. We recently developed a novel treadmill walking approach called dynamic treadmill walking that can provide asymmetric gait training by changing the treadmill speed between fast and slow speeds within a single stride. Here, we studied the energy expenditure associated with a variety of dynamic treadmill walking conditions. We hypothesized that the metabolic power required for dynamic treadmill walking in all conditions would approximate the metabolic power associated with conventional walking at the mean of the fast and slow speeds employed in the task. Eleven young adults without gait impairment walked on an instrumented treadmill and breathed into a metabolic measurement system. During dynamic treadmill walking, the treadmill fluctuated between 0.75m/s and 1.50m/s, each for 50% of an individuals stride time. We used a metronome to synchronize participants right heel-strikes with four different timing conditions. Net metabolic power during dynamic treadmill walking was significantly greater than normal walking at the mean speed of the task (1.125m/s) and generally lower than walking at the fast speed (1.5m/s). We did not observe any significant associations between net metabolic power and several measures of gait asymmetry during dynamic treadmill walking. These findings establish dynamic treadmill walking as a promising technique for improving gait symmetry in individuals who cannot tolerate fast treadmill walking, a common gait rehabilitation approach. Future work will assess the feasibility, metabolic demands, and clinical efficacy of using dynamic treadmill walking to improve gait symmetry in clinical populations. Key Points SummaryO_LIDynamic treadmill walking (i.e., walking with oscillating treadmill speeds) has previously been shown to drive gait asymmetries, but little is known about the energy expenditure required to complete the task. C_LIO_LIOur hypothesis was that dynamic treadmill walking would have similar metabolic power requirements to normal walking at a speed that is intermediate between the two dynamic treadmill walking speeds. C_LIO_LIWe found that dynamic treadmill walking actually requires metabolic power that is greater than the average of the two belt speeds, but less than that used for fast walking. C_LIO_LIDynamic treadmill walking is a promising and clinically translatable technique for rehabilitating populations with gait asymmetries that is not more energetically costly than fast treadmill walking, a common gait rehabilitation approach. C_LI

BACKGROUND: Aging and Parkinsons disease (PD) reduce gait automaticity and increase cognitive demand during walking. Although dual task (DT) paradigms investigate cognitive motor interference, evidence remains limited by heterogeneous tasks, predominant focus on prefrontal cortex (PFC) activity, and variability in functional near infrared spectroscopy (fNIRS) methods. This study investigates whether longitudinal changes in cortical activation during DT walking differ among young adults, older adults, and individuals with PD, and how these changes relate to DT costs over 5 years. METHODS: This longitudinal observational study follows STROBE and fNIRS guidelines and will be conducted in a controlled laboratory (Rede Amparo, CEPID NeuroMat, University of Sao Paulo). Participants will be evaluated annually under three randomized conditions: motor single-task walking, cognitive single task phonemic verbal fluency and DT walking with phonemic verbal fluency, each repeated 10 times. The primary outcome measure will be longitudinal changes in cortical activation during DT walking, quantified by oxygenated hemoglobin (HbO) signals measured with fNIRS in prefrontal and premotor cortical regions. The main predictors of interest will be motor and cognitive DT costs. Covariates will include age, sex, education, cognition, balance, mood, and disease severity in the PD group. Spatiotemporal gait parameters, including gait speed, step length, stride length, step time, base of support, double support, stance phase, and variability, will be recorded using the GAITRite system, and DT costs will be calculated for selected parameters. Cortical activation will be assessed using a 66 channel wearable fNIRS system with short separation channels. DISCUSSION: By combining randomized task blocks, separate motor and cognitive conditions, broader cortical coverage, and concurrent neural and gait assessment across three groups annually, this protocol is expected to provide a comprehensive characterization of cognitive motor interference during walking and its evolution, supporting interpretation of cortical and behavioral responses. The study may help distinguish age related adaptations from PD specific alterations and clarify whether increased cortical recruitment during DT gait reflects compensation, reduced neural efficiency, or ceiling effects, refining understanding of gait automaticity decline and informing rehabilitation and non invasive brain stimulation approaches.

Background: Freezing of gait (FOG) in Parkinson's disease (PD) is provoked by turning, doorways and dual-task walking. We evaluated WALK, a cadence-linked vibration neuromodulation combined with motor-learning training. Methods: Single-centre, sham-controlled pilot randomised trial. Adults with PD (Hoehn and Yahr 2 to 4) and neurologist-verified FOG were randomised 1:1 to intervention (WALK; vibration enabled) or sham (WALK; vibration disabled), alongside identical supervised home-based training for 6 weeks (3 sessions per week). OFF-medication assessments were performed at S0, S8 and S16. At S8 and S16, assessments were completed without a device and then with a device (fixed order). The primary endpoint was the mZ-FOG total (0 to 36). Results: Forty participants completed follow-up assessments (intervention n=24; sham n=16) with 100% session adherence and no serious device-related adverse events. In the intervention group, mZ-FOG total improved when assessed with the device at S8 ({Delta}=8.08) and S16 ({Delta}=9.21) relative to S0, with partial retention when assessed without the device at S16 ({Delta}=5.54). Conclusions: Cadence-linked, localised vibration neuromodulation plus motor-learning training was feasible and was associated with clinically meaningful within-intervention-group reductions in FOG. Taken together, the effect sizes and task-specific pattern support progression to a multicentre, assessor-blinded trial with an active sham, powered for between-group comparisons and durability and/or adherence endpoints.

Background and ObjectiveThe foot-ankle complex is a highly articulated and mechanically constrained system, often simplified as a chain of few rigid segments, neglecting many bone-to-bone motions and raising questions about the accurate representation of interaction with ground. This study proposes a new reduced-order multibody formulation that captures intrinsic kinematic constraints of the foot through motion synergies. MethodsBones kinematic coupling, or motion synergies, were experimentally derived from weight-bearing CT scans using principal component analysis. These couplings were embedded in a synergy-based multibody kinematic optimization framework describing the foot-ankle with five degrees of freedom: ankle flexion; foot adduction, pronation, and arching; and toe flexion. Model accuracy was evaluated against bone-level experimental kinematics. The model was applied to gait data from healthy, flat, and diabetic feet and compared with a standard multi-segment foot model, assessing robustness by progressively reducing the number of skin markers. ResultsAverage errors were about 1{degrees} and 0.5 mm when using subject-specific synergies and below 7{degrees} and 4 mm when scaling the generic model, matching or exceeding the accuracy of existing models. Reliable reconstruction was obtained using only four foot markers. In clinical gait analysis, the model showed superior discrimination between populations and enabled assessment of transverse arch deformation, not accessible with conventional models. ConclusionThe proposed synergy-based model provides an accurate, low-complexity framework for reconstructing bone-level foot and ankle kinematics, substantially simplifying gait analysis while improving biomechanical interpretability. This framework supports future integration with dynamic models aimed at studying load transmission in the foot.

Purpose: To identify, through iterative user-centered design, the auditory biofeedback requirements and sound preferences supporting gait training in children with cerebral palsy (CP), and to determine which feedback variables, sound mappings, and sound types yield clinically viable and movement-interpretable paradigms. Methods: The iterative process spanned two prototype phases. Prototype A comprised seven paradigms demonstrated to two experienced physiotherapists (Workshop 1A). Two of these were subsequently discarded owing to poor sound-movement interpretability and two were modified. Six paradigms were added to Prototype B, demonstrated to four children, five parents, and one therapist (Workshop 1B) and two therapists (Workshop 2B). Data were analyzed using systematic text condensation. Results: Within-child sound preferences varied with energy level and sensory state on a given day. Sound-movement interpretability tended to suffer for paradigms with greater acoustic complexity (e.g. computer-generated music). Therapists endorsed a repertoire spanning both movement quality and movement quantity targets. Participants independently proposed paradigms rewarding restrained and controlled movement, a feedback category absent from the current prototype. Conclusions: Session-level calibration is preferable to fixed sound profiles, requiring real-time interface support for paradigm adjustment. Acoustic complexity must remain subordinate to movement-sound interpretability. Paradigms targeting movement restraint are a development priority unaddressed in the literature.

Wearable digital health technologies may complement traditional gait assessments in amyotrophic lateral sclerosis (ALS) by sensitively capturing real-world mobility changes. In this study, we validated six digital gait metrics derived from ankle-worn sensors in a natural history cohort of 182 individuals with ALS. Investigated metrics correspond to various aspects of gait, including volume, speed, intensity, similarity, variability, and fragmentation. Longitudinal analyses showed significant declines in step count, peak cadence, stride intensity, and stride similarity, with increasing stride duration variability and walking fragmentation over 52 weeks. Many participants exhibited greater relative change in the gait metrics than the self-reported ALS Functional Rating Scale-Revised (ALSFRS-RSE). Stratified analyses revealed that digital metrics captured significant functional decline even in participants with stable walking scores on the ALSFRS-RSE. These findings support the potential utility of these metrics for disease monitoring in ALS clinical care and trials.

Background: Accurate evaluation of fine motor abilities is a key aspect of neurological rehabilitation. However, conventional approaches like goniometry are limited by variations among raters and their difficulty in detecting active movement. On the other hand, computer vision-based software delivers non-invasive and quantitative analysis of hand movements. An innovative computer-vision-based software tool, F.A.I.R. Chance(C), was developed to track and analyze individual finger joint movements on a camera-equipped laptop and give real-time numerical feedback. However, its metrics require validation in a healthy population before the tool can be used for clinical purposes. Objective: To assess the reliability and validity of finger movement assessment by the F.A.I.R. Chance computer vision-based tool in healthy adult participants. Methods: An observational cross-sectional study was done at MGM School of Physiotherapy, comprising 30 healthy participants between 18 and 60 years of age. Finger movements like flexion, extension, abduction, and adduction were measured with a standard handheld goniometer. These same finger movements were then measured with the tool at two time points separated by a 30-minute interval to determine the test-retest reliability. The tool's measurements were compared with the goniometric measurements to determine its concurrent validity. Test retest reliability was checked by the Intra-class Correlation Coefficient ICC (2,1), while concurrent validity was tested through Pearson's correlation coefficients. Results: Metacarpophalangeal and proximal interphalangeal joint motions demonstrated moderate to good test-retest reliability (ICC: 0.716-0.953) for the F.A.I.R. Chance tool. However, distal interphalangeal joint movements had lower consistency. Good reliability (ICC: 0.754-0.908) was seen for movements of abduction and adduction in the fingers. Strong concurrent validity for extension movements of the metacarpophalangeal joints (r=0.760-0.914) and moderate concurrent validity for flexion movements of the metacarpophalangeal joints (r=0.427-0.604) was demonstrated for all fingers for the F.A.I.R. Chance tool. Concurrent validity for adduction and abduction movements demonstrated a low to fair correlation with goniometric measurements (r=0.210-0.440). This is consistent with previous research showing poor agreement between goniometry and adduction-abduction movements of the fingers. Conclusion: The F.A.I.R. Chance tool shows good reliability and acceptable concurrent validity to assess fine motor movements in the healthy adult population. This sets a basis for further clinical study of the tool in the target population with fine motor impairments. Keywords: artificial intelligence; assistive technology; computer vision; fine motor evaluation; hand function;

Background Gait impairment is a central sign of cervical spondylotic myelopathy (CSM) that is typically evaluated through subjective patient-reported questionnaires or objective in-clinic measures. These systems require substantial resources to administer and are poorly suited for longitudinal monitoring, however, emerging smartphone applications present an efficient alternative. We developed and assessed the validity of a data processing framework based on the SynapTrack smartphone application to assess gait function in individuals with CSM. Methods Participants completed walking tasks which were recorded on both the SynapTrack app and a gold standard gait mat. Acceleration data extracted from the smartphone by the app were filtered and processed to produce gait cycle features including velocity, step time, waveform features and frequency domain features. Standard gait features were compared across the two methods by correlation and Bland-Altman plots to assess validity. App-based gait features were then compared to the standard modified Japanese Orthopedic Assessment (mJOA) assessment to determine construct validity through correlation and ability to discriminate between individuals with CSM and healthy controls. Finally, intraclass correlation coefficients and coefficients of variation were used to measure test-retest reliability and standard variation across app features. Results A total of 110 participants were included in this study, of which 55 (50%) had CSM, 24 (22%) had peripheral neuropathy, and 31 (28%) were healthy controls. SynapTrack gait measures including velocity, step time, and double support showed strong validity as indicated through Bland-Altman plots and high correlation (>0.8) with mat features. In addition to the gait features, acceleration root mean square, acceleration crest, spectral entropy, and dominant frequency showed strong construct validity compared to the mJOA across correlation (0.2-0.54), trend test (p < 0.001), and AUROC (0.62-0.79) analyses. ICCs showed moderate test-retest reliability (0.52-0.67). Discussion The proposed framework for processing gait data showed strong validity compared to the gold standard mat and high construct validity compared to the mJOA suggesting the utility of the SynapTrack app as an efficient alternative to existing methods. The confirmation of gait metrics related to CSM severity and identification of relevant waveform and frequency domain features present opportunities to use smartphone apps to develop ecologically valid data driven markers of CSM severity.

PurposeThe para-cycling classification system aims to minimize the impact of impairments on competition outcomes with the help of scientific evidence. This study investigated the impact of unilateral and bilateral ankle immobility on cycling performance, quantified by the maximal average mechanical power output (AMPO) over one revolution relative to that without ankle immobility. MethodsTen well-trained non-disabled cyclists performed all-out 6-second sprints on a cycle ergometer at 120 rpm under three conditions: without ankle foot orthoses (AFOs), with 1 AFO and with 2 AFOs immobilizing the ankle joint(s). Mechanical power output, pedal forces, cycling kinematics and surface-electromyography were measured. Maximal AMPO; ankle, knee and hip joint AMPO; and the amount of muscle excitation were calculated. ResultsWith 1 AFO and 2 AFOs, respectively, maximal AMPO was 96% (p<0.05) and 91% (p<0.001) of that without AFOs (1188 W). The decrease in maximal AMPO with ankle immobilization was less than the decrease in ankle joint AMPO (126 W decrease with 2 AFOs; p<0.001), due to an increase in hip joint AMPO (69 W increase with 2 AFOs; p<0.05). The amount of muscle excitation was not significantly different across conditions. ConclusionsThese findings provide a first quantitative and mechanistic indication of the impact of ankle immobility on cycling performance, which may offer valuable evidence to support the development of an evidence-based para-cycling classification system.

Biomechanical analysis of infant motor behavior is complicated by rapid growth and large inter-subject variability in body size and segment proportions. We present a growth-adjusted anthropometric scaling framework that integrates Centers for Disease Control and Prevention (CDC) growth charts with three-dimensional motion capture to estimate subject-specific infant biomechanics during prone play. Nineteen infants aged 2-6 months were recorded during spontaneous prone movement. Weight-for-age percentiles were computed using CDC LMS parameters and used to infer body length from length-for-age references, ensuring internal consistency between weight and length estimates. Body segments were scaled using published infant proportions and validated against head and shoulder widths measured from motion capture. Infant head and trunk proportions were substantially larger than adult values, whereas limb proportions were similar. Estimated and measured dimensions of head and trunk width showed good agreement, with mean root mean squared errors of approximately 3 cm. Adult-based scaling produced head and trunk length errors of up to 6 cm. This growth-adjusted framework improves anatomical fidelity and enables normalization of biomechanical measures across infants with differing growth trajectories.

Background Slow walking in older adults with mild parkinsonian signs (MPS) is a complex, multifactorial phenomenon arising from the cumulative burden of subclinical age-associated pathologies. This decline reflects age-associated neuronal loss in the dopaminergic system. A recent study suggests that levodopa treatment may enhance gait parameters. The goal of this small pilot study is to explore the effect of levodopa treatment on slow walking gait in older adults with MPS. Method This study was a randomized, placebo-controlled clinical pilot trial. Slow walking older adults without clinical evidence of PD were recruited and randomized into 2 groups (active treatment group or placebo control group). Participants in the active group were pre-treated with carbidopa for three days, followed by carbidopa-levodopa for seven days. Spatiotemporal gait parameters were evaluated at baseline and post-intervention. Results Gait factor analysis identified three main factors explaining gait characteristics at baseline, which included gait efficiency, gait rhythmicity, and gait turning.No effect of treatment was observed in the placebo group (p=0.111, p=0.616), no group difference was observed between the placebo and active group at baseline ({beta}=0.310, p=0.547), but a strong trend for a treatment-related increase was observed in the active treatment group ({beta}=0.506, p=0.076). Conclusion Our preliminary data suggest that sustained levodopa treatment (one week) in conjunction with carbidopa pre-treatment and concomitant carbidopa supplementation is feasible in slow walking older adults with MPS. Moreover, the data indicate potential efficacy, showing improvements in cadence, and step durations.

Background and Objectives: Cervical spondylotic myelopathy (CSM) is a leading cause of neurological disability in older adults. However, validated, scalable tools to quantify disease severity and changes over time are lacking. Recent advances in smartphone technology have opened new avenues for longitudinal, objective, and remote monitoring of neurological conditions. We performed a preliminary evaluation of the reliability and validity of SynapTrack, a smartphone-based digital platform for objective remote CSM assessments. Methods: In this single-center prospective cohort study, 265 participants (151 with CSM, 114 healthy controls) completed in-person SynapTrack assessments related to tapping, pinching, and vibratory detection, along with reference laboratory measures of dexterity (Box and Block Test, 9-Hole Peg Test) and vibratory sensation (tuning fork). A subset completed repeated home-based testing to assess test-retest reliability. We evaluated convergent validity, construct validity against the modified Japanese Orthopedic Association (mJOA) score, known-groups validity, and test-retest reliability (intraclass correlation coefficient, ICC). Results: Smartphone-derived metrics demonstrated good-to-excellent test-retest reliability, with the strongest stability for vibratory detection threshold (ICC = 0.92), overall and non-dominant tapping speed (ICC = 0.90 each), and pinching successful targets (ICC = 0.90). Convergent validity was supported by moderate-to-strong correlations between digital metrics and reference laboratory dexterity tests ({rho} up to 0.60 for tapping speed; up to -0.65 for the vibratory threshold). Construct validity against the mJOA was strongest for the vibratory threshold ({rho} = -0.53 to -0.54) and Level 2 non-dominant pinching errors ({rho} = -0.45). Selected metrics distinguished CSM patients from controls with good discrimination, including non-dominant tapping speed (AUROC = 0.76, 95% CI 0.68-0.85), Level 2 dominant pinching successful targets (AUROC = 0.78, 95% CI 0.62-0.94), and the non-dominant vibratory threshold (AUROC = 0.77, 95% CI 0.64-0.90). Conclusions and Relevance: A smartphone-based battery of upper-extremity sensorimotor tasks demonstrated preliminary reliability and validity in CSM. Furthermore, to our knowledge, the novel vibratory detection task represents the first smartphone-based sensory assessment used for CSM. Collectively, these findings position SynapTrack as a scalable platform for objective, remote neurological monitoring of CSM.

PurposeParkinsons disease (PD) is a neurodegenerative disease that affects motor control but can also influence sensory perception. Changes in vision and proprioception are well-documented but less is known about how PD alters auditory perception, particularly perception of speech acoustic properties. The current study examined perception of speech rate and intensity in PD and the relationship of auditory perception to disease severity. MethodPeople with PD were compared to age- and hearing-matched controls using perceptual tasks focused on discrimination and learning of speech rate and intensity. For rate discrimination, speech, non-speech, and visual stimuli were included to determine whether performance differences for PD participants and controls were specific to speech. Disease severity was assessed using the MDS-Unified Parkinsons Disease Rating Scale (MDS-UPDRS) and the relationship to performance on perceptual discrimination and learning tasks was evaluated. ResultsPeople with PD performed significantly worse than controls in the rate discrimination task for all types of stimuli. There were no significant group differences for intensity discrimination. However, participants with greater PD disease severity demonstrated significantly poorer intensity discrimination accuracy. Performance on learning tasks utilizing rate and intensity manipulations did not differ between PD and control participants and was unrelated to PD disease severity. ConclusionsPeople with PD had difficulty discriminating rate differences across speech, non-speech, and visual stimuli, indicating that challenges with rate perception are not limited to speech. The relationship between intensity discrimination and disease severity suggests common dopaminergic networks between motor symptoms and auditory perception in PD.

BackgroundHuntington disease (HD) is a neurological disorder caused by an aberrant CAG expansion in the HTT gene, producing a mutant protein (mHTT). Although HD is classically characterized by adult-onset cortical and striatal degeneration, accumulating evidence suggests that altered cortical development may also contribute to disease pathogenesis. ObjectiveWe sought to investigate the impact of mHTT on neocortical patterning, which is a largely unexplored aspect of HD. MethodsUsing the HdhQ140 HD knock-in mouse model, we performed immunofluorescence and in situ hybridization to analyze the patterning of the cortex from embryonic day 10 to postnatal day 7. ResultsDuring embryogenesis, HTT expression exhibited a high medial-to-low lateral gradient in the neocortex, like that observed for key transcription factors involved in cortical patterning. Notably, HTT expression was absent from the cortical hem, a critical patterning center. In HD, the protein gradient remained unchanged whereas the expression in medial pallium seemed increased. During the early development of the cerebral hemispheres, the expression of morphogens and signaling pathways, including Shh, Fgf8, and Wnt/BMP genes, were disrupted in organizing centers, leading to altered expression of major neocortical transcription factors. At postnatal stages, the motor and somatosensory cortical areas were misplaced. These developmental alterations were associated with postnatal sensorimotor deficits relevant to HD. ConclusionsOur findings demonstrate that HD-related neurodevelopmental alterations arise as early as embryonic day 10 in mice. This supports previous work suggesting that defects in brain development contribute to HD pathogenesis prior to clinical onset.