Visual impairments are common post-stroke and can lead to diminished functioning and difficulty accomplishing everyday tasks, such as reading and navigating unfamiliar environments independently. This pilot study investigates the usability, acceptability and preliminary efficacy of technological visuo-cognitive training (TVT) using the Senaptec Sensory Station for stroke survivors with visual field loss. Ten stroke survivors (8 males, 2 females; 43-79 years old; Mage = 65, SDage = 11.03) with a non-progressive visual field defect underwent TVT comprising baseline assessment, five 30-minute training sessions over 2-3 weeks, and post-intervention assessment. Measures of visual cognition, patient-reported outcomes, usability, and acceptability were assessed pre- and post-intervention, supplemented by qualitative interviews. Participants demonstrated meaningful gains in several aspects of visual search and functional vision. Reaction times on target capture tasks improved significantly, mirrored by more efficient performance on the Bell's Test. These behavioural changes aligned with reductions in reported visual difficulties and fatigue, both showing large effect sizes. Across sessions, participants also showed improvement in hand-eye coordination and visuomotor integration. Engagement with the system was high: perceived competence increased and usability ratings were excellent. Qualitative accounts contextualised these findings, describing enjoyment of the technology, occasional challenges related to adaptive difficulty or physical limitations, and perceived benefits such as greater awareness of visual scanning strategies in daily life. Notably, several sensory measures (e.g., visual clarity, contrast sensitivity, depth perception) remained unchanged, indicating that improvements were domain-specific rather than global. Overall, TVT demonstrated acceptability with selective improvements in visual search function and vision-related quality of life. Larger randomised controlled trials are needed to determine efficacy and comparative effectiveness against standard rehabilitation approaches.

Background Postural instability is one of the most debilitating symptoms of Parkinson’s disease (PD). It is also major concern in healthy older adults (OA), contributing to increased fall risk. Cognitive function plays a critical role in postural control. However, little is known about the specific cognitive domains related to postural control in these populations. This study aimed to examine how postural control relates to different domains of cognitive function across varying standing sensory conditions, and how these associations are influenced by age, PD and PD severity. Methods A total of 232 participants (127 people with PD (PwPD) aged 69.51 (7.67)), 52 OA (aged 68.78 (7.92) and 53 younger adults (YA) (aged 23.58 (4.02) were assessed across two sites. PwPD were also categorised based on Hoehn and Yahr (H&Y) stage I, II and III. Participants completed cognitive tests and four standing tasks (eyes open/closed, firm/foam surface). Sway measures (area, velocity, jerkiness, root mean square, and frequency) were collected using six wearable inertial sensors. Hierarchical linear regression analysis examined cognitive predictors of sway within each group. Results Regression analyses revealed group-specific cognitive-postural associations. In PwPD, OA, YA, and H&Y II, better executive function was linked to increased sway outcomes. Conclusions Increased sway outcomes may reflect a more flexible, adaptive postural control strategy, while reduced sway outcomes may reflect a more constrained postural strategy linked to poorer cognition. These findings highlight the importance of considering performance on specific cognitive domains, age, and disease severity when assessing postural control and fall risk in OA and PwPD.

Pupil response may be a useful biomarker in Parkinson’s disease (PD) due to links with autonomic function and cognitive load. However, research has focused on static tasks, missing functional demands during real-world activities like walking. Methods: We recruited 38 people with PD and 16 healthy controls who walked for 2 min under single- and dual-task conditions while wearing mobile eye-tracking glasses (Tobii Pro Glasses 2, 100 Hz). Pupil response outcomes (velocity, size, difference between eyes) were extracted alongside gait characteristics from inertial sensors. Known groups validity compared PD and controls; convergent/divergent validity examined relationships with cognitive, visual, clinical, and gait measures. Results: People with PD had significantly altered pupil constriction/dilation velocity (p = 0.01), a larger difference between their left and right pupils (p = 0.04), and a larger mean and minimum pupil size (p ≤ 0.01) compared to controls during walking. Pupil response correlated with cognitive function (JLO, CLOX1, TMTB), visual acuity, disease severity (MDS-UPDRS-III), and gait characteristics in both groups. No dual-task effects were observed. Conclusions: Pupil response during walking demonstrates known groups and convergent validity, indicating potential as a clinical biomarker for PD. Following this initial study, more research is required to further validate pupil response in PD (e.g., analytical validation and testing within real-world ecologically valid environments).

BACKGROUND:Postural instability is one of the most debilitating symptoms of Parkinson's disease (PD). Moreover, older adults (OA) often show issues with postural control leading to increased fall-risk. However, the current understanding of the neural underpinnings of standing postural control remains limited. This study aims to investigate cortical control of postural control in OA, younger adults (YA), and people with PD (PwPD), using functional near-infrared spectroscopy (fNIRS). METHODS:A total of four 2-minute standing conditions were performed. Postural control and cortical activity were recorded in 80 PwPD, 33 OA, and 38 YA. A wireless fNIRS system recorded changes in relative oxygenated haemoglobin (∆HbO2) across cortical regions including the prefrontal cortex (PFC), supplementary motor area (SMA), primary motor cortex (M1), primary somatosensory cortex (S1), and primary visual cortex (V1). Six wearable sensors provided sway outcome measures (area, jerkiness velocity, root mean square, and frequency). RESULTS:Sway outcomes were greater across several conditions in PwPD. Significant group effects were found with increased ∆HbO2 in the PFC in PD compared to OA. Moreover, YA had increased ∆HbO2 in the S1 compared to OA and PD. CONCLUSIONS:PwPD showed greater PFC recruitment, indicating reliance on executive-attentional resources for balance. In contrast, YA engaged somatosensory regions more strongly, suggesting that ageing may affect the integration of sensory information for postural control. Findings support interventions that (a) reduce executive load during balance in PD and (b) bolster somatosensory integration in ageing.

BACKGROUND:Mobility impairment is influenced by intrinsic Parkinson's disease (PD) factors but also by extrinsic/environmental factors, such as indoor vs. outdoor locations as well as terrain type. Most existing studies address human activity recognition (HAR) and terrain classification separately and often focus on healthy cohorts. There remains a need for an integrated framework that enables contextual mobility assessment in people with PD (PwPD) using wearable sensors. METHODS:In this exploratory pilot study, we developed a unified multimodal wearable framework based on a one-dimensional convolutional neural network (1D-CNN) to perform HAR and terrain recognition in PwPD. A local dataset was collected from ten PwPD using synchronised inertial measurement units (IMUs) and surface electromyography (sEMG) sensors positioned on the lower back and lower limbs. The model was evaluated under three sensor configurations (M1, lower-back IMU; M2, individual IMU windows pooled across four lower-limb sensor locations; M3, corresponding IMU+sEMG windows pooled across the same locations). External benchmark evaluation was conducted using the UCI-HAR, WISDM and Uneven Walking Surface IMU datasets to assess the applicability of the same architecture across independent datasets. RESULTS:On the local dataset, HAR accuracy increased from 0.786 with M1 to 0.889 with M3, while terrain classification accuracy increased from 0.821 to 0.881. Participant-level analysis showed significant differences across configurations for activity accuracy (p = 0.032, W = 0.383), precision (p = 0.001, W = 0.753) and F1-score (p = 0.008, W = 0.531). For terrain classification, significant differences were observed for recall and F1-score (both p = 0.025, W = 0.370). When independently retrained on the external datasets, the same architectural design achieved accuracies of 0.976 on UCI-HAR, 0.981 on WISDM and 0.875 on the Uneven Walking Surface dataset, demonstrating the applicability of the same architecture across independent datasets. CONCLUSION:The proposed framework supports both HAR and terrain classification in PwPD using a common architecture and provides a basis for combining activity and environmental context in wearable mobility assessment. The findings provide preliminary evidence of performance differences across sensor configurations.

Ocular microtremor (OMT) is an involuntary fixational eye movement linked to brainstem activity. OMT is thought to have a mean frequency range of 70-90 Hz in healthy adults. Previous research suggests OMT may be reduced in neurological diseases like Parkinson's Disease. Historically, OMT has been measured invasively in specialist laboratories using lengthy and expensive protocols. Developments now allow for OMT measurement quickly and non-invasively using hand-held technology (i.e., iTremor ONE). This pilot study aimed to examine the analytical and clinical validation of OMT measurement via the iTremor ONE in people with Parkinson's Disease (PwPD). 33 PwPD and 31 age matched healthy controls participated in this study. For analytical validation, 22 PwPD completed a test re-test reliability assessment of OMT measurement, assessed using interclass correlation coefficients (ICC). For clinical validation, OMT frequency in PwPD (n = 33) was compared to controls. Correlations were explored with demographics and clinical scales. Additionally, 24 PwPD were tested 'OFF' (12hr withdrawal) and 'ON' their anti-Parkinson's (dopaminergic) medication to compare OMT response to a known intervention. The iTremor ONE demonstrated excellent test-retest reliability (ICC > 0.9) for measuring OMT frequency in PwPD. Mean OMT frequency was significantly lower in PwPD (63.78 ± 4.82 Hz) compared to controls (69.44 ± 6.47 Hz, p < .001), with good discriminative ability (AUC 0.75-0.77). OMT frequency correlated with age in both groups and with specific motor features (speech, facial expression, gait) in PwPD. No significant differences in OMT frequency were observed between 'OFF' and 'ON' dopaminergic medication states. This is the first study to demonstrate that a non-invasive hand-held device can reliably measure OMT in PwPD and presents OMT analytical and clinical validation evidence. OMT frequency may provide a supporting measure for diagnosis or screening. Further research is required to understand the neural mechanisms underpinning OMT in PwPD and the role it could play in clinical practice.

ABSTRACT Objective Gait impairment is a distinctive symptom of Parkinson's disease that negatively impact mobility. We assessed the validity of wearable digital insoles against a validated reference gait analysis system for measuring select gait characteristics in patients with Parkinson's disease. Methods A comparative analysis between digital insoles (Moticon ReGo Insole) and the GAITRite system was conducted in patients with Parkinson's disease. Patients were assessed in both the OFF and ON medication states. Gait characteristics were measured simultaneously with both systems during two 10 m walk tests. Patients also completed a patient experience survey following the use of the digital insoles. Results Overall, 21 patients with Parkinson's disease were included in the study. Analytical validation for gait cadence, speed, and stride length showed excellent agreement (intraclass correlation coefficients between 0.93–0.97) in both the OFF and ON states. Stance, swing, and double support times exhibited lower validity with moderate agreement (intraclass correlation coefficients from 0.48–0.57). Gait speed and stride length were significantly associated with scores on the Movement Disorders Society's Unified Parkinson's Disease Rating Scale (p = 0.0085 and 0.013, respectively). Mean differences in all parameters measured with the insoles, except cadence, were significantly different between OFF and ON states (p < 0.003). The majority of patients liked wearing the digital insoles and found them comfortable and user‐friendly. Interpretation These findings support the validity of Moticon ReGo digital insoles for the assessment of several important gait characteristics in Parkinson's disease.

This study investigated whether a lower volume of once-weekly resistance training (RT) could elicit meaningful improvements in quality of life (QoL), functional capacity and strength in untrained older adults, aiming to determine if reduced training volume could yield meaningful adaptations. The study included 31 community-dwelling older adults (mean age 66.7 ± 4.9 years; 55 % female) with a mean body mass index (BMI) of 27.2 kg/m². Participants were randomised into four groups to perform a leg press exercise using either maximal-intent (MI; defined as the purposeful intention to move as fast as possible regardless of resistance) or controlled-tempo (CT) RT across two volumes (3 ×5 or 5 ×5, sets × repetitions) at 60 % one-repetition maximum (1RM) once weekly for six weeks. Body mass, BMI, QoL (assessed by the SF-36) were assessed, and a follow-up QoL survey conducted three months post-intervention. Functional capacity was evaluated using balance, six-minute walk (6MWT), timed-up-and-go (TUG), and 30-second sit-to-stand (30sSTS) tests. Strength was measured via leg press 1RM, knee extension maximum voluntary isometric contractions (MVIC), and strength-to-mass ratio. All assessments were conducted at baseline, mid-intervention (week 3) and post-intervention (week 6) to compare the effectiveness of both shorter (3-week) and full-length (6-week) training periods. Low-dose RT significantly enhanced QoL, functional capacity, and strength (p < 0.05) across all groups within the first three weeks. Both CT and MI modalities led to significant strength improvements (p < 0.001), with no statistically significant difference between modalities (p > 0.05). Despite the reduced volume, the 3 × 5 protocol achieved comparable outcomes to 5 × 5, suggesting that meaningful adaptations can be achieved with lower training volumes. These findings support the efficacy of short-term, lower-dose RT interventions for untrained older adults.

ObjectiveExamine cortical activation patterns in Huntington's disease (HD) under single-task (ST) and dual-task (DT) balance conditions compared to controls using portable functional near-infrared spectroscopy (fNIRS).BackgroundIndividuals with HD have difficulty multitasking while performing balance tasks, so previously automatic tasks may require more attentional resources to maintain stability and prevent falls. Our understanding of the neural mechanisms underlying the relationship between impaired cognition and balance in HD is minimal. fNIRS provides a noninvasive means to functionally image the brain under ecologically valid conditions to understand the neural underpinnings of impaired balance in HD.MethodsEighteen HD (56.2 ± 9.8 years) and 20 age-matched control participants (57.4 ± 11.2 years) completed ST/ DT balance testing with eyes open (EO) or eyes closed (EC) wearing inertial sensors and fNIRS to collect spatiotemporal balance variables with concurrent prefrontal (PFC) and posterior parietal (PPC) cortical activity monitoring. The cognitive DT was the Controlled Oral Word Association Test during 3, 30-second trials.ResultsIndividuals with HD had significantly lower PPC activity during the EO DT condition compared to controls (P = .007). Unlike controls, there were no differences in PFC or PPC activation across balance conditions in HD, despite significantly worsening postural sway during DT conditions (P < .0001).ConclusionOur findings suggest that individuals with HD are unable to increase cortical activation during challenging DT conditions suggesting a recruitment ceiling was reached during ST conditions. Furthermore, individuals with HD may not be able to increase cortical recruitment in response to increasing task difficulty.

The analysis of running gait has conventionally taken place within an expensive and restricted laboratory space, with wearable technology offering a practical, cost-effective, and unobtrusive way to examine running gait in more natural environments. This pilot study presents a wearable inertial measurement unit (IMU) setup for the continuous analysis of running gait during an outdoor parkrun (i.e., 5 km). The study aimed to (1) provide analytical validation of running gait measures compared to time- and age-graded performance and (2) explore performance validation. Ten healthy adults (7 females, 3 males, mean age 37.2 ± 11.7 years) participated. The participants wore Axivity AX6 IMUs on the talus joint of each foot, recording tri-axial accelerometer and gyroscope data at 200 Hz. Temporal gait characteristics—gait cycle, ground contact time, swing time, and duty factor—were extracted using zero-crossing algorithms. The data were analyzed for correlations between the running performance, foot strike type, and fatigue-induced changes in temporal gait characteristics. Strong correlations were found between the performance time and both the gait cycle and ground contact time, with weak correlations for foot strike types. The analysis of asymmetry and fatigue highlighted modest changes in gait as fatigue increased, but no significant gender differences were found. This setup demonstrates potential for in-field gait analysis for running, providing insights for performance and injury prevention strategies.

Parkinson's disease (PD) can cause postural instability, which may result in falls. These issues have been associated with motor and non-motor symptoms (NMS), including cognitive dysfunction. Several techniques have been employed to investigate the underlying neural mechanisms involved in postural control in PD. These include behavioural studies assessing associations between cognition and postural control, functional neuroimaging studies, and resting-state neural correlates. This review provides an overview of these emerging bodies of research. Scopus, PubMed, and ProQuest were searched and detailed the brain-imaging technique, cohort, and postural control measures. A total of 79 studies were identified. Findings supported the notion of cortical involvement in postural control function to compensate for subcortical damage resulting from PD. Future studies should standardise their outcome measures and data analysis to allow comparisons of results across studies and ensure more comprehensive and robust data collection to enhance the reliability and validity of these findings.

BACKGROUND:Gait impairment in Parkinson's disease (PD) occurs early and pharmaceutical interventions do not fully restore this function. Visual cueing has been shown to improve gait and alleviate freezing of gait (FOG) in PD. Technological development of digital laser shoe visual cues now allows for visual cues to be used continuously when walking. This study aimed to investigate the effects of laser shoe visual cueing on gait in people with PD across different disease severity (i.e., Hoehn & Yahr [H&Y] stages I-III) and FOG status. METHODS:Eighty people with PD (H&YI = 20, H&YII = 30 [15 FOG, 15 noFOG], H&YIII = 30 [15 FOG, 15 noFOG]) walked a 10 m straight path (back and forth) self-paced for 80 seconds without and then with laser shoe cues (participants were allowed 1-2 walks to familiarize with the cues). Inertial sensors were used to measure gait metrics. Laser cue line was set to usual step length for individuals based on their usual walk data from the inertial sensors. RESULTS:Laser shoe cueing did not improve gait in PD regardless of disease severity or FOG status. Across all groups, participants decreased gait speed (P < .001), cadence (P < .001), arm range of motion (P < .005), and increased stride time, double support time (P < .001), elevation at midswing (P < .001), and gait variability (P < .001) with the laser shoes compared to usual walking. CONCLUSION:Digital laser shoe visual cues do not improve gait in people with PD across disease severity or FOG status. Further investigation is required to examine different cue settings or exposure periods.

Background Internal and external cueing strategies are often applied to alleviate gait deficits in Parkinson’s disease (PD). However, it remains unclear which type of cueing strategy is most effective at different disease stages. The underlying neural mechanisms of response to cueing are also unknown. Objective To investigate the immediate response of multiple brain cortical regions and gait to internal and external cueing in people at different stages of PD. Methods People with PD (n = 80) were split into groups dependent on their disease stage (Hoehn and Yahr [H&Y] stage I to III). Participants performed a baseline walk without cues followed by randomized cued walking conditions (internal and external [visual, auditory and tactile] cues). A combined functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) system assessed cortical brain activity while walking. Wearable inertial sensors assessed gait. Results Cue-related gait improvements were not influenced by H&Y stage; moderate or large effect sizes were only observed for internal cueing and external visual cueing. fNIRS findings suggested cortical response was similar across H&Y stages, with increased activity in the prefrontal cortex with internal cues; and increased activity in the primary motor and visual cortices with external cues. However, EEG showed that people with PD in H&YIII had higher parietal alpha power than those in H&YI in the auditory, tactile, and visual cueing conditions. Conclusion Gait improvement with cueing was similar across PD stages and underpinned by cognitive, motor, and/or sensory neural processing within selective brain regions that may be influenced by PD stage (i.e., parietal cortex).

Stroboscopic visual training is a novel rehabilitation technique which involves training under conditions of intermittent vision to enhance visual and perceptual skills. Stroboscopic glasses may be a useful adjunct to rehabilitation for people with neurological conditions, but very little is known about what it is like to train under conditions of interrupted vision. This study explores the experience of using stroboscopic glasses as a novel, digital adjunct to exercise for people with Parkinson’s. This qualitative study is embedded in a pilot randomised controlled trial investigating technological visuo-cognitive training in people with Parkinson’s. A subset of participants who used stroboscopic glasses as part of the trial were interviewed between January and November 2022. Individual semi-structured interviews were conducted in participant homes. Transcribed data were coded and analysed thematically. Level of active participation with the strobe training was measured with the Pittsburgh Rehabilitation Participation Scale to add context to the qualitative data. Sixteen people with Parkinson’s were interviewed. Three overarching themes were identified: (1) The stroboscopic experience; (2) Acceptability of the strobe glasses; (3) Evaluation of stroboscopic visual training. Pittsburgh Rehabilitation Participation Scale scores significantly increased from 3.6 after the first session to 4.7 at the final session (p = < 0.001) indicating improved participation in the strobe training Our study shows that in a supervised context, strobe glasses are an acceptable adjunct to exercise for people with Parkinson’s. However, reactions to the stroboscopic effect and fear of falling may affect independent use. Based on our findings, we make recommendations for future clinical research using strobe glasses in relation to eligibility criteria, methodology and risk assessment. Further work is required to explore the feasibility and efficacy of stroboscopic visual training in Parkinson’s disease to support its use in clinical practice. This trial was listed on the ISRCTN registry with study ID ISRCTN46164906 on 21 April 2021.

The Senaptec Sensory Station (SSS) is a device that can measure visual acuity (VA) and contrast sensitivity (CS), but validity has not been established in clinical populations. Therefore, we examined analytical and initial clinical validation of VA and CS measured via the SSS in Parkinson’s disease (PD). SSS was used in 34 PD (aged 69.6 (SD = 9.4) years old) to measure VA (via visual clarity outcome) and CS (via SSS-CS6 and SSS-CS18 outcomes). Analytical validation was performed through comparison to reference VA and CS eye-charts (ETDRS VA, MARS CS), and clinical validation was performed through correlation with clinical measures. Difference in VA LogMar score between the reference eye chart and the SSS was − 0.03 (0.23); e.g., approximately a single letter on the eye chart. There was moderate agreement between the SSS and eye chart VA measurement in PD (ICC = 0.42). Additionally, there was moderate correlation between SSS and eye chart (0.8 cpd) CS measurement in PD, specifically for SSS-CS6 (6 cpd) (r = 0.46). However, there was poor correlation between eye chart and SSS-CS18 (18 cpd). SSS VA and CS measures correlated moderately with cognitive function, disease duration and severity, providing clinical validation evidence. VA and CS can be measured with SSS in PD with moderate comparability to reference eye charts (dependent on cpd for CS), and digital outcomes may provide clinically meaningful outcomes to use in PD trials. A range of human, technological and protocol factors may impact validity of VA and CS measurement via SSS, which should be further examined in future studies.

Ocular microtremor (OMT) is a fixational eye movement that cannot be seen with the naked eye but is always present, even when the eye appears motionless/still. The link between OMT and brain function provides a strong rationale for investigation as there lies potential for its use as a biomarker in populations with neurological impairments. OMT frequency is typically 70-80Hz in healthy adults and research suggests that this will be reduced in those with neurological disease such as Parkinson's Disease (PD). This study aims to examine OMT in people with PD compared to healthy older adults. This is an exploratory, observational study that will use a novel handheld device-The iTremor ONE, which has been developed to rapidly, non-invasively assess and evaluate OMT frequency. This device uses incident laser technology directed at the sclera. People with PD who meet the inclusion criteria will participate in a home-based assessment involving cognitive, motor (using the UPDRS-III) and OMT measures. With OMT as the primary outcome, assessment with the iTremor is quick, taking just three seconds to obtain a reading. People with PD will be invited into the laboratory to perform extensive cognitive assessments along with an assessment of balance, gait, and turning using wearable sensors. People with PD will be assessed both off, and on, their anti-parkinsonian medication following a 12 hour washout period. We will recruit 30 People with PD, 30 people with suspected PD and 30 age-matched healthy control participants for assessment of OMT. 20 People with PD will complete a test-retest reliability assessment at the same approximate time, exactly one week after their initial visit under the same conditions to explore consistency. This will be the first study of its kind to non-invasively investigate OMT frequency as a marker/monitor for PD with advanced technology that could be used within the clinic, laboratory, or home. Identifying OMT as a PD biomarker could better support clinical assessment, enabling improved provision of care to patients with advanced disease monitoring. Clinical trial registration: This trial is registered at clinicaltrials.gov (NCT06051877; September 2023).