Free-water imaging of the cholinergic basal forebrain and pedunculopontine nucleus in Parkinson's disease.

Free-water imaging can predict and monitor dopamine system degeneration in people with Parkinson's disease. It can also enhance the sensitivity of traditional diffusion tensor imaging (DTI) metrics for indexing neurodegeneration. However, these tools are yet to be applied to investigate cholinergic system degeneration in Parkinson's disease, which involves both the pedunculopontine nucleus and cholinergic basal forebrain. Free-water imaging, free-water-corrected DTI and volumetry were used to extract structural metrics from the cholinergic basal forebrain and pedunculopontine nucleus in 99 people with Parkinson's disease and 46 age-matched controls. Cognitive ability was tracked over 4.5 years. Pearson's partial correlations revealed that free-water-corrected DTI metrics in the pedunculopontine nucleus were associated with performance on cognitive tasks that required participants to make rapid choices (behavioural flexibility). Volumetric, free-water content and DTI metrics in the cholinergic basal forebrain were elevated in a sub-group of people with Parkinson's disease with evidence of cognitive impairment, and linear mixed modelling revealed that these metrics were differently associated with current and future changes to cognition. Free water and free-water-corrected DTI can index cholinergic degeneration that could enable stratification of patients in clinical trials of cholinergic interventions for cognitive decline. In addition, degeneration of the pedunculopontine nucleus impairs behavioural flexibility in Parkinson's disease, which may explain this region's role in increased risk of falls.

Back to 'normal'? BMI, physical fitness and health-related quality of life of children from North East England before, during and after the COVID-19 lockdowns.

We assessed whether changes in children's body mass index (BMI), physical fitness and health-related quality of life observed post-2020 United Kingdom COVID-19 lockdown remained 12 and 18 months later. Twenty-metre shuttle run test (20mSRT), handgrip strength, standing broad jump, sit-and-reach, height, body mass, and health-related quality of life (Kidscreen27 questionnaire) were measured in 90 children (8-9 years) during October 2019 ("T0"), November 2020 ("T1"), November 2021 ("T2") and June 2022 ("T3"). Mixed-effects models showed age- and sex-normalised BMI increased from T0 (mean: 0.71) to T1 (0.97), remaining elevated at T2 (0.95) and T3 (0.89). Decreases in 20mSRT performance were observed from T0 (22.0) to T1 (19.3), then increased at T2 (23.5) and T3 (28.3). Standing broad jump and handgrip strength increased over time. The proportion of children with overweight/obesity increased from T0 (32%) to T3 (48%). Health-related quality of life decreased for "Physical Wellbeing" yet increased for "Autonomy & Parents". Our findings highlight that lockdowns may have had lasting implications for children's health, and the urgent need to reduce overweight and obesity in North East England. Improving health and fitness behaviours to maximise long-term health outcomes and build resilience to future emergencies and disruptions to health behaviours is also paramount.

Sweat Characteristics and Fluid Balance Responses During Two Heat Training Camps in Elite Female Field Hockey Players.

We examined the sweat characteristics and fluid balance of elite female field hockey players during two heat training camps. Fourteen elite female field hockey players from the Australian national squad participated in two heat training camps held ∼6 months apart, following winter- (Camp 1) and summer-based training (Camp 2). Daily waking body mass (BM) and urine specific gravity (USG) were collected, along with several markers of sweat and fluid balance across two matches per camp. There was a 19% mean reduction in estimated whole-body sweat sodium concentration from Camp 1 (45.8 ± 6.5 mmol/L) to Camp 2 (37.0 ± 5.0 mmol/L; p < .001). Waking urine specific gravity ≥ 1.020 was observed in 31% of samples, with no significant differences in mean urine specific gravity or BM between camps (p > .05), but with substantial interindividual variation. Intramatch sweat rates were high (1.2-1.8 L/hr), with greater BM losses in Camp 1 (p = .030), resulting in fewer players losing ≥2% BM in Camp 2 (0%-8%), as compared with Camp 1 (36%-43%; p = .017). Our field data suggest that elite female field hockey players experience substantial sweat losses during competition in the heat regardless of the season. In agreement with previous findings, we observed substantial interindividual variation in sweat and hydration indices, supporting the use of individualized athlete hydration strategies.

High-Intensity Running During International Male Field Hockey Involves Frequent Changes of Direction and Repeated Accelerations but Seldom Reaches Sprint Velocities.

ABSTRACT: Goods, PS, Appleby, B, Scott, BR, Peeling, P, and Galna, B. High-intensity running during international male field hockey involves frequent changes of direction and repeated accelerations but seldom reaches sprint velocities. J Strength Cond Res XX(X): 000-000, 2024-The aim of this investigation was to quantify the characteristics of high-intensity running in international male field hockey. Player movement data were collected through wearable player tracking devices across 3 tournaments (17 matches) from 27 members of the Australian male field hockey team (totaling 266 player matches). Active duration (minute), high-intensity efforts (>2.5 m·s-2 for >1 second), repeated high-intensity efforts (≥3 efforts with ≤45-second recovery between efforts), and sprints (>7 m·s-1) were extracted and aggregated for each player match. The duration, distance, mean and peak speed, mean change of direction and straightness for each high-intensity effort, and peak deceleration at the conclusion of each effort were calculated. Mixed-effects models were used to estimate the mean for each outcome (fixed effect), with random intercepts modeled for player and match. On average, players completed 42.2 high-intensity efforts and 2.1 sprints per match. High-intensity efforts were short (3.61 seconds, 12.9 m), failed to reach high velocities (average peak velocity: 4.8 m·s-1), and involved frequent changes of direction (56% of efforts were not straight). There were 4.7 bouts of repeated high-intensity efforts per player, per match (comprising 3.8 efforts, with 3.53 seconds per effort separated by 16.2-second recovery). Last, we also found that 29% of high-intensity efforts involved a high-speed deceleration (>3.5 m·s-2), and these occurred frequently when in conjunction with a >45° (86%) or >90° (89%) change of direction. We recommend practitioners focus on developing players' ability to repeatedly accelerate, decelerate, and change direction over short distances and adopt testing and monitoring programs that assess these qualities.

Physical preparation of the Australian national male field hockey team exceeded the movement demands of the Tokyo 2020 Olympic Games tournament.

This investigation explored differences in the pre-tournament preparation period relative to the movement demands of the Tokyo 2020 Olympic Games for the Australian male field-hockey team. Movement data was collected over 7 months prior to and during the 13-day Olympic tournament. Duration, distance (total; >80% individual peak velocity; >5 m.s-1), high-speed decelerations (>3.5 m.s-2), and total accelerations and decelerations (>2.5 m.s-2) were measured during each running-based session. A 13-day moving sum was calculated for each variable and compared to a player-specific "worst-case scenario" (WCS) for intra-tournament total movement demands. Summed 13-day movement demands exceeded the WCS for 6-58% of the preparation period across variables, for the entire squad. During the tournament, midfielders covered significantly greater sprint distance than Defenders (+84%,p = 0.020), with no other positional differences found. Greater variation in tournament movement demands was observed between players for accelerations, decelerations, and high-speed distance (CV = 19-46%) compared to duration and distance (CV = 4-9%). In conclusion, physical preparation exposed athletes to movement demands which surpassed WCS. Additionally, gross measures of training volume (duration and distance) are more generalisable to a squad; however, additional metrics such as sprint distance and high-speed decelerations are needed to better define positional and individual movement demands, and therefore, should be monitored by practitioners.

Gait-Related Metabolic Covariance Networks at Rest in Parkinson's Disease.

BACKGROUND: Gait impairments are characteristic motor manifestations and significant predictors of poor quality of life in Parkinson's disease (PD). Neuroimaging biomarkers for gait impairments in PD could facilitate effective interventions to improve these symptoms and are highly warranted. OBJECTIVE: The aim of this study was to identify neural networks of discrete gait impairments in PD. METHODS: Fifty-five participants with early-stage PD and 20 age-matched healthy volunteers underwent quantitative gait assessment deriving 12 discrete spatiotemporal gait characteristics and [18 F]-2-fluoro-2-deoxyglucose-positron emission tomography measuring resting cerebral glucose metabolism. A multivariate spatial covariance approach was used to identify metabolic brain networks that were related to discrete gait characteristics in PD. RESULTS: In PD, we identified two metabolic gait-related covariance networks. The first correlated with mean step velocity and mean step length (pace gait network), which involved relatively increased and decreased metabolism in frontal cortices, including the dorsolateral prefrontal and orbital frontal, insula, supplementary motor area, ventrolateral thalamus, cerebellum, and cuneus. The second correlated with swing time variability and step time variability (temporal variability gait network), which included relatively increased and decreased metabolism in sensorimotor, superior parietal cortex, basal ganglia, insula, hippocampus, red nucleus, and mediodorsal thalamus. Expression of both networks was significantly elevated in participants with PD relative to healthy volunteers and were not related to levodopa dosage or motor severity. CONCLUSIONS: We have identified two novel gait-related brain networks of altered glucose metabolism at rest. These gait networks could serve as a potential neuroimaging biomarker of gait impairments in PD and facilitate development of therapeutic strategies for these disabling symptoms. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Changes in children's physical fitness, BMI and health-related quality of life after the first 2020 COVID-19 lockdown in England: A longitudinal study.

We aimed to assess one-year changes in physical fitness, health-related quality of life (HRQoL) and body mass index (BMI), encompassing the 2020 COVID-19 UK lockdowns. Data were collected (October 2019, November 2020) from 178 8-10-year-olds in Newcastle-upon-Tyne, England, 85% from England's most deprived quintile. Twenty-metre shuttle run test performance (20mSRT), handgrip strength (HGS), standing broad jump (SBJ), sit-and-reach, height, body mass, HRQoL (Kidscreen-27 questionnaire) and sports club participation were measured. BMI z-scores and overweight/obesity were calculated (≥85th centile). Paired t-tests and linear regression assessed change, adjusting for baseline BMI. Significant (p<0.001) changes were observed: increases in mean BMI (+1.5kg·m-2), overweight/obesity (33% to 47%), SBJ (+6.8cm) and HGS (+1.5kg); decreases in 20mSRT performance (-3 shuttles), sit-and-reach (-1.8cm). More children at follow-up were categorized "very low" for 20mSRT performance (35% baseline v 51%). Increased BMI z-score was associated with decreased "Physical Wellbeing" HRQoL. Follow-up sports club participation was associated with better 20mSRT performance (p=0.032), and "Autonomy & Parents" (p=0.011), "Social Support & Peers" (p=0.038) HRQoL. Children's 20mSRT performance and BMI changed adversely over one year; national lockdowns potentially made negative contributions. Physical fitness, physical activity and sports programmes should be part of children's physical and mental recovery from the pandemic.

Cholinergic Basal Forebrain Volumes Predict Gait Decline in Parkinson's Disease.

BACKGROUND: Gait disturbance is an early, disabling feature of Parkinson's disease (PD) that is typically refractory to dopaminergic medication. The cortical cholinergic system, originating in the nucleus basalis of Meynert of the basal forebrain, has been implicated. However, it is not known if degeneration in this region relates to a worsening of disease-specific gait impairment. OBJECTIVE: To evaluate associations between sub-regional cholinergic basal forebrain volumes and longitudinal progression of gait impairment in PD. METHODS: 99 PD participants and 47 control participants completed gait assessments via an instrumented walkway during 2 minutes of continuous walking, at baseline and for up to 3 years, from which 16 spatiotemporal characteristics were derived. Sub-regional cholinergic basal forebrain volumes were measured at baseline via MRI and a regional map derived from post-mortem histology. Univariate analyses evaluated cross-sectional associations between sub-regional volumes and gait. Linear mixed-effects models assessed whether volumes predicted longitudinal gait changes. RESULTS: There were no cross-sectional, age-independent relationships between sub-regional volumes and gait. However, nucleus basalis of Meynert volumes predicted longitudinal gait changes unique to PD. Specifically, smaller nucleus basalis of Meynert volume predicted increasing step time variability (P = 0.019) and shortening swing time (P = 0.015); smaller posterior nucleus portions predicted shortening step length (P = 0.007) and increasing step time variability (P = 0.041). CONCLUSIONS: This is the first study to demonstrate that degeneration of the cortical cholinergic system predicts longitudinal progression of gait impairments in PD. Measures of this degeneration may therefore provide a novel biomarker for identifying future mobility loss and falls. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The Impact of Environment on Gait Assessment: Considerations from Real-World Gait Analysis in Dementia Subtypes.

Laboratory-based gait assessments are indicative of clinical outcomes (e.g., disease identification). Real-world gait may be more sensitive to clinical outcomes, as impairments may be exaggerated in complex environments. This study aims to investigate how different environments (e.g., lab, real world) impact gait. Different walking bout lengths in the real world will be considered proxy measures of context. Data collected in different dementia disease subtypes will be analysed as disease-specific gait impairments are reported between these groups. Thirty-two people with cognitive impairment due to Alzheimer's disease (AD), 28 due to dementia with Lewy bodies (DLB) and 25 controls were recruited. Participants wore a tri-axial accelerometer for six 10 m walks in lab settings, and continuously for seven days in the real world. Fourteen gait characteristics across five domains were measured (i.e., pace, variability, rhythm, asymmetry, postural control). In the lab, the DLB group showed greater step length variability (p = 0.008) compared to AD. Both subtypes demonstrated significant gait impairments (p < 0.01) compared to controls. In the real world, only very short walking bouts (<10 s) demonstrated different gait impairments between subtypes. The context where walking occurs impacts signatures of gait impairment in dementia subtypes. To develop real-world gait assessment as a clinical tool, algorithms and metrics must accommodate for changes in context.

Gait analysis with wearables predicts conversion to parkinson disease.

OBJECTIVE: Quantification of gait with wearable technology is promising; recent cross-sectional studies showed that gait characteristics are potential prodromal markers for Parkinson disease (PD). The aim of this longitudinal prospective observational study was to establish gait impairments and trajectories in the prodromal phase of PD, identifying which gait characteristics are potentially early diagnostic markers of PD. METHODS: The 696 healthy controls (mean age = 63 ± 7 years) recruited in the Tubingen Evaluation of Risk Factors for Early Detection of Neurodegeneration study were included. Assessments were performed longitudinally 4 times at 2-year intervals, and people who converted to PD were identified. Participants were asked to walk at different speeds under single and dual tasking, with a wearable device placed on the lower back; 14 validated clinically relevant gait characteristics were quantified. Cox regression was used to examine whether gait at first visit could predict time to PD conversion after controlling for age and sex. Random effects linear mixed models (RELMs) were used to establish longitudinal trajectories of gait and model the latency between impaired gait and PD diagnosis. RESULTS: Sixteen participants were diagnosed with PD on average 4.5 years after first visit (converters; PDC). Higher step time variability and asymmetry of all gait characteristics were associated with a shorter time to PD diagnosis. RELMs indicated that gait (lower pace) deviates from that of non-PDC approximately 4 years prior to diagnosis. INTERPRETATION: Together with other prodromal markers, quantitative gait characteristics can play an important role in identifying prodromal PD and progression within this phase. ANN NEUROL 2019;86:357-367.

Factors That Influence Habitual Activity in Mild Cognitive Impairment and Dementia.

BACKGROUND: Reduced engagement with habitual activity (HA) is associated with greater risk and progression of cognitive decline and falls in older adults and people with dementia. Understanding external and intrinsic factors that affect HA may provide novel targets for non-pharmacologic interventions. OBJECTIVE: This study primarily aims to identify factors that influence HA in normal ageing and cognitive impairment, such as cognitive and motor problems and disease subtype. METHODS: 108 older adults participated in this study; 36 with cognitive impairment due to Alzheimer's disease (AD), 30 with dementia with Lewy bodies (DLB), 16 with Parkinson's disease dementia (PDD), and 26 controls. A tri-axial accelerometer recorded continuous data of volume, variability, and pattern of HA over 7 days. Participants undertook a battery of cognitive and neuropsychological assessments. RESULTS: One-way analysis of variance controlling for age and gender shows that people with DLB and PDD engage less with HA than controls (p ≤ 0.01), but there were no significant differences between AD and controls (p ≥ 0.01). Multivariate analysis demonstrated motor disease and impairments in activities of daily living (ADLs) independently explained 10-26% of volume, variability, and pattern of HA in people with cognitive impairment. CONCLUSION: People with cognitive impairment have reduced HA engagement compared to controls. Motor disease and impairments in ADLs most strongly contribute to these findings and may be important to consider for disease management. Wearable technology can provide a personalised picture of an individual's daily behaviours and may be a useful tool for person-centred care.

Turning Detection During Gait: Algorithm Validation and Influence of Sensor Location and Turning Characteristics in the Classification of Parkinson's Disease.

Parkinson's disease (PD) is a common neurodegenerative disorder resulting in a range of mobility deficits affecting gait, balance and turning. In this paper, we present: (i) the development and validation of an algorithm to detect turns during gait; (ii) a method to extract turn characteristics; and (iii) the classification of PD using turn characteristics. Thirty-seven people with PD and 56 controls performed 180-degree turns during an intermittent walking task. Inertial measurement units were attached to the head, neck, lower back and ankles. A turning detection algorithm was developed and validated by two raters using video data. Spatiotemporal and signal-based characteristics were extracted and used for PD classification. There was excellent absolute agreement between the rater and the algorithm for identifying turn start and end (ICC ≥ 0.99). Classification modeling (partial least square discriminant analysis (PLS-DA)) gave the best accuracy of 97.85% when trained on upper body and ankle data. Balanced sensitivity (97%) and specificity (96.43%) were achieved using turning characteristics from the neck, lower back and ankles. Turning characteristics, in particular angular velocity, duration, number of steps, jerk and root mean square distinguished mild-moderate PD from controls accurately and warrant future examination as a marker of mobility impairment and fall risk in PD.

Comparison of Walking Protocols and Gait Assessment Systems for Machine Learning-Based Classification of Parkinson's Disease.

Early diagnosis of Parkinson's diseases (PD) is challenging; applying machine learning (ML) models to gait characteristics may support the classification process. Comparing performance of ML models used in various studies can be problematic due to different walking protocols and gait assessment systems. The objective of this study was to compare the impact of walking protocols and gait assessment systems on the performance of a support vector machine (SVM) and random forest (RF) for classification of PD. 93 PD and 103 controls performed two walking protocols at their normal pace: (i) four times along a 10 m walkway (intermittent walk-IW), (ii) walking for 2 minutes on a 25 m oval circuit (continuous walk-CW). 14 gait characteristics were extracted from two different systems (an instrumented walkway-GAITRite; and an accelerometer attached at the lower back-Axivity). SVM and RF were trained on normalized data (accounting for step velocity, gender, age and BMI) and evaluated using 10-fold cross validation with area under the curve (AUC). Overall performance was higher for both systems during CW compared to IW. SVM performed better than RF. With SVM, during CW Axivity significantly outperformed GAITRite (AUC: 87.83 ± 7.81% vs. 80.49 ± 9.85%); during IW systems performed similarly. These findings suggest that choice of testing protocol and sensing system may have a direct impact on ML PD classification results and highlight the need for standardization for wide scale implementation.

Do Alzheimer's and Lewy body disease have discrete pathological signatures of gait?

OBJECTIVE: We aimed to refine the hypothesis that dementia has a unique signature of gait impairment reflective of underlying pathology by considering two dementia subtypes, Alzheimer's disease (AD) and Lewy body disease (LBD), and exploring the role of cognition in disease-specific gait impairments. BACKGROUND: Accurately differentiating AD and LBD is important for treatment and disease management. Early evidence suggests gait could be a marker of dementia due to associations between discrete gait characteristics and cognitive domains. UPDATED HYPOTHESIS: We hypothesize that AD and LBD have unique signatures of gait, reflecting disease-specific cognitive profiles and underlying pathologies. An exploratory study included individuals with mild cognitive impairment or dementia due to LBD (n = 45) and AD (n = 36) and 29 older adult controls. An instrumented walkway quantified 16 gait characteristics reflecting five independent domains of locomotion (pace, rhythm, variability, asymmetry, and postural control). The LBD group demonstrated greater impairments in asymmetry and variability compared with AD; both groups were more impaired in pace and variability domains than controls. Executive dysfunction explained 11% of variance for gait variability in LBD, whereas global cognitive impairment explained 13.5% of variance in AD; therefore, gait impairments may reflect disease-specific cognitive profiles. With a refined hypothesis that AD- and LBD-specific signatures of gait reflect discrete pathologies, future studies must examine the relationship between a validated model of gait with neural networks, using recognized biomarkers and postmortem follow-up. MAJOR CHALLENGES FOR HYPOTHESIS: Differential diagnosis of AD and LBD used appropriate criteria and required consensus from an expert diagnostic panel to improve diagnostic accuracy. Future work should follow the framework set out in Parkinson's disease to establish unique signatures of gait as proxy measures of disease-specific pathology; that is, use a validated gait model to explore the progressive relationship between gait, cognition, and pathology. LINKAGE TO OTHER MAJOR THEORIES: These exploratory findings support the theory of interacting cognitive-motor networks, as the gait-cognition relationship may reflect cognitive control over motor networks. Unique signatures of gait may reflect different temporal patterns of pathological burden in neural areas related to cognitive and motor function.

Saccade frequency response to visual cues during gait in Parkinson's disease: the selective role of attention.

Gait impairment is a core feature of Parkinson's disease (PD) with implications for falls risk. Visual cues improve gait in PD, but the underlying mechanisms are unclear. Evidence suggests that attention and vision play an important role; however, the relative contribution from each is unclear. Measurement of visual exploration (specifically saccade frequency) during gait allows for real-time measurement of attention and vision. Understanding how visual cues influence visual exploration may allow inferences of the underlying mechanisms to response which could help to develop effective therapeutics. This study aimed to examine saccade frequency during gait in response to a visual cue in PD and older adults and investigate the roles of attention and vision in visual cue response in PD. A mobile eye-tracker measured saccade frequency during gait in 55 people with PD and 32 age-matched controls. Participants walked in a straight line with and without a visual cue (50 cm transverse lines) presented under single task and dual-task (concurrent digit span recall). Saccade frequency was reduced when walking in PD compared to controls; however, visual cues ameliorated saccadic deficit. Visual cues significantly increased saccade frequency in both PD and controls under both single task and dual-task. Attention rather than visual function was central to saccade frequency and gait response to visual cues in PD. In conclusion, this study highlights the impact of visual cues on visual exploration when walking and the important role of attention in PD. Understanding these complex features will help inform intervention development.

Direct and indirect effects of attention and visual function on gait impairment in Parkinson's disease: influence of task and turning.

Gait impairment is a core feature of Parkinson's disease (PD) which has been linked to cognitive and visual deficits, but interactions between these features are poorly understood. Monitoring saccades allows investigation of real-time cognitive and visual processes and their impact on gait when walking. This study explored: (i) saccade frequency when walking under different attentional manipulations of turning and dual-task; and (ii) direct and indirect relationships between saccades, gait impairment, vision and attention. Saccade frequency (number of fast eye movements per-second) was measured during gait in 60 PD and 40 age-matched control participants using a mobile eye-tracker. Saccade frequency was significantly reduced in PD compared to controls during all conditions. However, saccade frequency increased with a turn and decreased under dual-task for both groups. Poorer attention directly related to saccade frequency, visual function and gait impairment in PD, but not controls. Saccade frequency did not directly relate to gait in PD, but did in controls. Instead, saccade frequency and visual function deficit indirectly impacted gait impairment in PD, which was underpinned by their relationship with attention. In conclusion, our results suggest a vital role for attention with direct and indirect influences on gait impairment in PD. Attention directly impacted saccade frequency, visual function and gait impairment in PD, with connotations for falls. It also underpinned indirect impact of visual and saccadic impairment on gait. Attention therefore represents a key therapeutic target that should be considered in future research.

Influence of Cueing and an Attentional Strategy on Freezing of Gait in Parkinson Disease During Turning.

BACKGROUND AND PURPOSE: Individuals with Parkinson disease exhibit decreased axial head-pelvis rotation. Consequently, they turn more en bloc than healthy controls, which may contribute to freezing during turning. We wanted to understand the influence of auditory cueing and an attentional strategy on turning and how this related to freezing of gait (FOG). METHODS: Fifteen participants with Parkinson disease and FOG were asked to turn 180° during baseline condition, unilateral cueing, and an attentional strategy prompting to start the turn with head rotation first. FOG occurrence, axial rotation, center of mass (COM) deviation, knee-flexion amplitude, and total turn velocity were measured using 3D motion analysis while off-medication. Normal reference values were obtained from 14 age-matched controls. RESULTS: Thirty-nine FOG episodes occurred in 5 participants. FOG occurred in 52.8% of baseline trials compared with 34.6% of trials using the head-first strategy, and 3.8% of the auditory cueing trials. During the head first strategy, the initiation of head, trunk, and pelvic rotation as well as the head-pelvis separation resembled turning patterns of healthy controls, but the COM shift to the inside of the turn was exaggerated. By contrast, during cueing, turning became more en bloc, with decreased head-pelvis separation and knee-flexion amplitude. DISCUSSION AND CONCLUSIONS: Cueing reduced FOG but did not correct axial movement deficits. The head-first strategy improved head-pelvis dissociation but had only limited effects on FOG. These results suggest that axial and COM deviation impairments are not directly related to FOG but may rather indicate a compensatory mechanism. Cueing reinforced the en-bloc movement and might as such help prevent FOG by triggering an alternative neural mechanism for movement generation.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A163).

Predicting first fall in newly diagnosed Parkinson's disease: Insights from a fall-naïve cohort.

BACKGROUND: Falls are common and associated with reduced independence and mortality in Parkinson's disease. Previous research has been conducted on falls-prevalent or advanced disease cohorts. OBJECTIVE: This study identifies risk factors for first fall for 36 months in a newly diagnosed, falls-naïve cohort. METHODS: A total of 121 consecutive Parkinson's disease patients were recruited. Falls data were collected prospectively during 36 months from diagnosis via monthly falls diaries and telephone follow-up for 117 participants. Assessment comprised a comprehensive battery of clinical, gait, and cognitive measures. Significant predictors were identified from decision-tree analysis and survival analysis with time to first fall during 36 months as the dependent variable. FINDINGS: At baseline, 26 (22%) participants reported retrospective falls. At 36 months, the remaining cohort (n = 91) comprised 47 fallers (52%) and 30 (33%) nonfallers and 14 (15%) participants with incomplete diaries. Fallers presented with a significantly higher disease severity, poorer ability to stand on one leg, slower gait speed, increased stance time variability, and higher swing time asymmetry. Median time to first fall was 847 days. Gait speed, stance time, and Hoehn & Yahr III stage emerged as significant predictors of first fall, hazard ratio 3.44 (95% confidence interval [CI] 1.58 to 7.48), 3.31(95% CI 1.40 to 7.80), and 2.80 (95% CI 1.38 to 5.65), respectively. The hazard ratio for risk factors combined was 7.82 (CI 2.80 to 21.84). CONCLUSIONS: Interventions that target gait deficit and postural control in early Parkinson's disease may limit the potential for first fall. © 2016 International Parkinson and Movement Disorder Society.

Free-living gait characteristics in ageing and Parkinson's disease: impact of environment and ambulatory bout length.

BACKGROUND: Gait is emerging as a powerful diagnostic and prognostic tool, and as a surrogate marker of disease progression for Parkinson's disease (PD). Accelerometer-based body worn monitors (BWMs) facilitate the measurement of gait in clinical environments. Moreover they have the potential to provide a more accurate reflection of gait in the home during habitual behaviours. Emerging research suggests that measurement of gait using BWMs is feasible but this has not been investigated in depth. The aims of this study were to explore (i) the impact of environment and (ii) ambulatory bout (AB) length on gait characteristics for discriminating between people with PD and age-matched controls. METHODS: Fourteen clinically relevant gait characteristics organised in five domains (pace, variability, rhythm, asymmetry, postural control) were quantified using laboratory based and free-living data collected over 7 days using a BWM placed on the lower back in 47 PD participants and 50 controls. RESULTS: Free-living data showed that both groups walked with decreased pace and increased variability, rhythm and asymmetry compared to walking in the laboratory setting. Four of the 14 gait characteristics measured in free-living conditions were significantly different between controls and people with PD compared to two measured in the laboratory. Between group differences depended on bout length and were more apparent during longer ABs. ABs ≤ 10s did not discriminate between groups. Medium to long ABs highlighted between-group significant differences for pace, rhythm and asymmetry. Longer ABs should therefore be taken into account when evaluating gait characteristics in free-living conditions. CONCLUSION: This study provides encouraging results to support the use of a single BWM for free-living gait evaluation in people with PD with potential for research and clinical application.

Viewing 3D TV over two months produces no discernible effects on balance, coordination or eyesight.

With the rise in stereoscopic 3D media, there has been concern that viewing stereoscopic 3D (S3D) content could have long-term adverse effects, but little data are available. In the first study to address this, 28 households who did not currently own a 3D TV were given a new TV set, either S3D or 2D. The 116 members of these households all underwent tests of balance, coordination and eyesight, both before they received their new TV set, and after they had owned it for 2 months. We did not detect any changes which appeared to be associated with viewing 3D TV. We conclude that viewing 3D TV does not produce detectable effects on balance, coordination or eyesight over the timescale studied. Practitioner Summary: Concern has been expressed over possible long-term effects of stereoscopic 3D (S3D). We looked for any changes in vision, balance and coordination associated with normal home S3D TV viewing in the 2 months after first acquiring a 3D TV. We find no evidence of any changes over this timescale.