Hybrid approaches to allied health services for children and young people: a scoping review.

BACKGROUND: Hybrid models that integrate both in-person and remote health services are increasingly recognized as a promising approach. Nevertheless, research that defines and characterizes these models in children and young people is scarce and essential for establishing guidelines for implementation of hybrid allied health services. This scoping review evaluates four key aspects of hybrid allied health services in children and young people: 1. definitions, 2. service characteristics, 3. outcome measures, and 4. results of hybrid allied health services. METHODS: Six databases were searched: Medline (Ovid), Embase, CINHAL, Psycinfo, Cochrane CENTRAL, and Web of Science. Of the 9,868 studies potentially meeting the inclusion criteria, 49 studies focused on children and young people. Following full-text review, n = 21 studies were included. RESULTS: Terminology used for hybrid allied health services varied across studies which targeted diverse clinical populations and varied in study design, type and frequency of remote and in-person treatments. Over 75% of cases used custom-written software, limiting scalability. All interventions started in-person, possibly to establish a therapeutic alliance and solve technological issues. Most hybrid allied health services (67%) were in mental health, while only a minority involved physical, occupational or speech therapy. The most common outcomes were feasibility and satisfaction, but tools used to measure them were inconsistent. Although 57% of studies demonstrated effectiveness of hybrid allied health services, none measured cost-effectiveness. DISCUSSION: Despite the potential of hybrid allied health services for children and young people, the literature remains at a preliminary stage. Standardization of definitions and outcome measures, and clearer reporting of service characteristics and results would likely promote consolidation of hybrid allied health services in children and young people into clinical practice.

The effect of co-dependent (thinking in motion [TIM]) versus single-modality (CogniFit) interventions on cognition and gait among community-dwelling older adults with cognitive impairment: a randomized controlled study.

BACKGROUND: Cognition and motor skills are interrelated throughout the aging process and often show simultaneous deterioration among older adults with cognitive impairment. Co-dependent training has the potential to ameliorate both domains; however, its effect on the gait and cognition of older adults with cognitive impairment has yet to be explored. The aim of this study is to compare the effects of the well-established single-modality cognitive computerized training program, CogniFit, with "Thinking in Motion (TIM)," a co-dependent group intervention, among community-dwelling older adults with cognitive impairment. METHODS: Employing a single-blind randomized control trial design, 47 community-dwelling older adults with cognitive impairment were randomly assigned to 8 weeks of thrice-weekly trainings of TIM or CogniFit. Pre- and post-intervention assessments included cognitive performance, evaluated by a CogniFit battery, as a primary outcome; and gait, under single- and dual-task conditions, as a secondary outcome. RESULTS: CogniFit total Z scores significantly improved from baseline to post-intervention for both groups. There was a significant main effect for time [F (1, 44) = 17.43, p < .001, ηp2 = .283] but not for group [F (1, 44) = 0.001, p = .970]. No time X group interaction [F (1, 44) = 1.29, p = .261] was found. No changes in gait performance under single and dual-task performance were observed in both groups. CONCLUSIONS: The findings show that single-modality (CogniFit) and co-dependent (TIM) trainings improve cognition but not gait in older adults with cognitive impairment. Such investigations should be extended to include various populations and a broader set of outcome measurements. TRIAL REGISTRATION: ACTRN12616001543471. Date: 08/11/2016.

Organisation of services and systems of care in paediatric spinal cord injury rehabilitation in seven countries: a survey with a descriptive cross-sectional design.

STUDY DESIGN: International multicentre cross-sectional study. OBJECTIVES: To describe the organisation and systems of paediatric spinal cord injury (SCI) rehabilitation services in seven countries and compare them with available recommendations and key features of paediatric SCI. SETTING: Ten SCI rehabilitation units in seven countries admitting children and adolescents with SCI < 18 years of age. METHODS: An online survey reporting data from 2017. Descriptive and qualitative analysis were used to describe the data. RESULTS: The units reported large variations in catchment area, paediatric population and referrals, but similar challenges in discharge policy. Nine of the units were publicly funded. Three units had a paediatric SCI unit. The most frequent causes of traumatic injury were motor vehicle accidents, falls, and sports accidents. Unlike the other units, the Chinese units reported acrobatic dancing as a major cause. Mean length of stay in primary rehabilitation ranged between 18 and 203 days. Seven units offered life-long follow-up. There was a notable variation in staffing between the units; some of the teams were not optimal regarding the interdisciplinary and multiprofessional nature of the field. Eight units followed acknowledged standards and recommendations for specialised paediatric SCI rehabilitation and focused on family-centred care and rehabilitation as a dynamic process adapting to the child and the family. CONCLUSIONS: As anticipated, we found differences in the organisation and administration of rehabilitation services for paediatric SCI in the ten rehabilitation units in seven countries. This might indicate a need for internationally approved, evidence-based guidelines for specialised paediatric SCI rehabilitation.

Factors associated with Multidisciplinary Healthcare Resource Utilization Following Discharge from Pediatric Rehabilitation: A One-year Follow-up Study.

AIMS: To characterize multidisciplinary healthcare resource utilization (mHRU), including physical, occupational, speech and psychosocial therapy one-year following discharge from prolonged inpatient and outpatient pediatric rehabilitation in Israel and to identify factors associated with long-term mHRU. METHODS: According to Andersen's model of health service use, predisposing (child's age and sex), enabling (district of origin, income level, parental education, insurance) and need factors (injury type, functional status, family psychosocial risk) were collected from parents of children hospitalized for >1 month in a large rehabilitation hospital in Israel, and phone interviews were held 3-months (T1), 6-months (T2) and 12-months (T3) post-discharge. The effect of time and the role of various factors on mHRU, operationalized as number of therapy sessions in the previous 2 weeks, were evaluated. RESULTS: Sixty-one families participated at T1 and T2, and 46 participated at T3. HRU was similar over time. Predisposing factors (age) and need factors (functional status and psychosocial risk) were associated with specific disciplines of mHRU, but enabling factors were not. CONCLUSIONS: mHRU is high and stable 12-months post-discharge. The lack of impact of enabling factors on mHRU, and the discipline-specific impact of predisposing and need factors, support equity of care provision for children following prolonged rehabilitation.

Factors associated with dynamic balance in people with Persistent Postural Perceptual Dizziness (PPPD): a cross-sectional study using a virtual-reality Four Square Step Test.

BACKGROUND: Persistent postural-perceptual dizziness (PPPD) is a condition characterized by chronic subjective dizziness and exacerbated by visual stimuli or upright movement. Typical balance tests do not replicate the environments known to increase symptoms in people with PPPD-crowded places with moving objects. Using a virtual reality system, we quantified dynamic balance in people with PPPD and healthy controls in diverse visual conditions. METHODS: Twenty-two individuals with PPPD and 29 controls performed a square-shaped fast walking task (Four-Square Step Test Virtual Reality-FSST-VR) using a head-mounted-display (HTC Vive) under 3 visual conditions (empty train platform; people moving; people and trains moving). Head kinematics was used to measure task duration, movement smoothness and anterior-posterior (AP) and medio-lateral (ML) ranges of movement (ROM). Heart rate (HR) was monitored using a chest-band. Participants also completed a functional mobility test (Timed-Up-and-Go; TUG) and questionnaires measuring anxiety (State-Trait Anxiety Inventory; STAI), balance confidence (Activities-Specific Balance Confidence; ABC), perceived disability (Dizziness Handicap Inventory) and simulator sickness (Simulator Sickness Questionnaire). Main effects of visual load and group and associations between performance, functional and self-reported outcomes were examined. RESULTS: State anxiety and simulator sickness did not increase following testing. AP-ROM and HR increased with high visual load in both groups (p < 0.05). There were no significant between-group differences in head kinematics. In the high visual load conditions, high trait anxiety and longer TUG duration were moderately associated with reduced AP and ML-ROM in the PPPD group and low ABC and  high perceived disability were associated with reduced AP-ROM (|r| = 0.47 to 0.53; p < 0.05). In contrast, in controls high STAI-trait, low ABC and longer TUG duration were associated with increased AP-ROM (|r| = 0.38 to 0.46; p < 0.05) and longer TUG duration was associated with increased ML-ROM (r = 0.53, p < 0.01). CONCLUSIONS: FSST-VR may shed light on movement strategies in PPPD beyond task duration. While no main effect of group was observed, the distinct associations with self-reported and functional outcomes, identified using spatial head kinematics, suggest that some people with PPPD reduce head degrees of freedom when performing a dynamic balance task. This supports a potential link between spatial perception and PPPD symptomatology.

Will virtual rehabilitation replace clinicians: a contemporary debate about technological versus human obsolescence.

This article is inspired by a pseudo Oxford-style debate, which was held in Tel Aviv University, Israel at the International Conference on Virtual Rehabilitation (ICVR) 2019, which is the official conference of the International Society for Virtual Rehabilitation. The debate, between two 2-person teams with a moderator, was organized by the ICVR Program committee to address the question "Will virtual rehabilitation replace clinicians?" It brought together five academics with technical, research, and/or clinical backgrounds-Gerry Fluet, Tal Krasovsky, Anat Lubetzky, Philippe Archambault, W. Geoffrey Wright-to debate the pros and cons of using virtual reality (VR) and related technologies to help assess, diagnose, treat, and track recovery, and more specifically investigate the likelihood that advanced technology will ultimately replace human clinicians. Both teams were assigned a side to defend, whether it represented their own viewpoint or not, and to take whatever positions necessary to make a persuasive argument and win the debate. In this paper we present a recapitulation of the arguments presented by both sides, and further include an in-depth consideration of the question. We attempt to judiciously lay out a number of arguments that fall along a spectrum from moderate to extreme; the most extreme and/or indefensible positions are presented for rhetorical and demonstrative purposes. Although there may not be a clear answer today, this paper raises questions which are related to the basic nature of the rehabilitation profession, and to the current and potential role of technology within it.

DataSpoon: Validation of an Instrumented Spoon for Assessment of Self-Feeding.

Clinically feasible assessment of self-feeding is important for adults and children with motor impairments such as stroke or cerebral palsy. However, no validated assessment tool for self-feeding kinematics exists. This work presents an initial validation of an instrumented spoon (DataSpoon) developed as an evaluation tool for self-feeding kinematics. Ten young, healthy adults (three male; age 27.2 ± 6.6 years) used DataSpoon at three movement speeds (slow, comfortable, fast) and with three different grips: "natural", power and rotated power grip. Movement kinematics were recorded concurrently using DataSpoon and a magnetic motion capture system (trakSTAR). Eating events were automatically identified for both systems and kinematic measures were extracted from yaw, pitch and roll (YPR) data as well as from acceleration and tangential velocity profiles. Two-way, mixed model Intraclass correlation coefficients (ICC) and 95% limits of agreement (LOA) were computed to determine agreement between the systems for each kinematic variable. Most variables demonstrated fair to excellent agreement. Agreement for measures of duration, pitch and roll exceeded 0.8 (excellent agreement) for >80% of speed and grip conditions, whereas lower agreement (ICC < 0.46) was measured for tangential velocity and acceleration. A bias of 0.01-0.07 s (95% LOA [-0.54, 0.53] to [-0.63, 0.48]) was calculated for measures of duration. DataSpoon enables automatic detection of self-feeding using simple, affordable movement sensors. Using movement kinematics, variables associated with self-feeding can be identified and aid clinical reasoning for adults and children with motor impairments.

Despite dystonia: natural history of delayed-onset pediatric secondary dystonia.

Background: Dystonia is a movement disorder involving involuntary movements and/or postures of the limbs, trunk, neck or face. Secondary dystonia following brain injury is uncommon, with unfavorable long-term consequences. Given the limited evidence regarding pediatric secondary dystonia, this study's aim was to document the natural history of the condition and the effect of interventions on its symptomatology. Methods: We describe three cases of girls (age 8 to 11 y) who developed dystonia secondary to an acquired brain injury, received intensive rehabilitation treatments and were followed for 8-33 months post-injury. In all three cases, secondary dystonia appeared 1-3 months post-insult. Results: In none of the cases was there alleviation of dystonic symptoms over time despite physical and pharmacological interventions; in two cases the dystonic hand is now used as an assisting hand only, whereas in the third it is completely non-functional. However, despite their impairment, two girls achieved basic functional independence and one is partly independent in activities of daily living. Conclusions: Rehabilitation professionals who work with pediatric patients susceptible to developing secondary dystonia should be aware of its possible consequences and inform families and staff. Intensive task-specific training during rehabilitation may be key to regaining overall functional capabilities despite residual impairment.

Movement control in patients with shoulder instability: a comparison between patients after open surgery and nonoperated patients.

BACKGROUND: Open surgery to correct shoulder instability is deemed to facilitate recovery of static and dynamic motor functions. Postoperative assessments focus primarily on static outcomes (e.g., repositioning accuracy). We introduce kinematic measures of arm smoothness to assess shoulder patients after open surgery and compare them with nonoperated patients. Performance among both groups of patients was hypothesized to differ. Postsurgery patients were expected to match healthy controls. METHODS: All participants performed pointing movements with the affected/dominant arm fully extended at fast, preferred, and slow speeds (36 trials per subject). Kinematic data were collected (100 Hz, 3 seconds), and mixed-design analyses of variance (group, speed) were performed with movement time, movement amplitude, acceleration time, and model-observed similarities as dependent variables. Nonparametric tests were performed for number of velocity peaks. RESULTS: Nonoperated and postsurgery patients showed similarities at preferred and faster movement speeds but not at slower speed. Postsurgery patients were closer to maximally smoothed motion and differed from healthy controls mainly during slow arm movements (closer to maximal smoothness, larger movement amplitude, shorter movement time, and lower number of peaks; i.e., less movement fragmentation). CONCLUSIONS: Arm kinematic analyses suggest that open surgery stabilizes the shoulder but does not necessarily restore normal movement quality. Patients with recurrent anterior shoulder instability (RASI) seem to implement a "safe" but nonadaptive mode of action whereby preplanned stereotypical movements may be executed without depending on feedback. Rehabilitation of RASI patients should focus on restoring feedback-based movement control. Clinical assessment of RASI patients should include higher order kinematic descriptors.

Trait anxiety increases the attentional cost of walking in young adults: A cross-sectional study.

BACKGROUND: Anxiety is a prevalent mental health disorder, with debilitating symptoms causing avoidance and decreased quality of life. Balance impairments during standing and walking are common in anxiety. However, understanding of gait control mechanisms in people with trait anxiety, particularly when walking requires increased attention (dual-task), is still limited. This work examined the attentional cost of walking in people with varying levels of trait anxiety. Since people with anxiety are often prone to Space and Motion Discomfort (SMD), this work also evaluated the potential role of SMD in the attentional cost of walking. METHODS: Fifty-six participants, aged 18-51, classified as anxious and non-anxious, were asked to walk under single- and two dual-task conditions (cognitive: counting backwards; visuomotor: texting on a mobile phone). Task performance (walking, counting and texting) was measured. Prefrontal cortex (PFC) activation was recorded using functional near infrared spectroscopy (fNIRS) for a subset of participants (n = 29). RESULTS: Anxious individuals walked slower under dual-task conditions, with smaller increases in PFC activation from single to dual-task conditions in the cognitive task. Dual-task walking was unrelated to SMD. LIMITATIONS: sample size was limited, particularly for fNIRS data. CONCLUSIONS: To the best of our knowledge, this study is the first to identify anxiety-related deficits in attentional gait control in the general population, including during the everyday task of texting on a mobile phone. Since decrements in dual-task walking are linked to poor health outcomes, results from this work may have functional implications for people with anxiety.

The Effect of Total Knee Replacement on Dual-Task Gait Performance in Older Adults.

OBJECTIVE: Total knee replacement (TKR) is a common solution for patients with advanced knee osteoarthritis (OA). Still, fall rates remain relatively high after surgery. TKR may alter pain and knee function, balance control, and proprioception. However, given the role of complex (dual-task) walking in fall prediction for older adults, it is unknown how TKR alters the attentional demand of walking in older adults. The goal of this study was to examine the effect of TKR on dual-task walking among older adults. METHODS: Participants were evaluated 1 month before surgery and 4.5 months after surgery. Participants walked along an instrumented 7-meter path for 1 minute with and without a cognitive task (serial-3 subtraction). Pain and knee function, knee proprioception, dynamic balance, and balance confidence, as well as dual-task costs (DTC) were compared before and after the surgery and factors associated with change in gait DTCs were assessed. RESULTS: Thirty-eight participants completed the study (age 72.6 years, SD = 4.9; 11 men). A significant decrease in pain was found following TKR, with no change in balance, balance confidence, or proprioception. There were no differences in gait DTCs before and after the surgery. However, change in dynamic balance, specifically reactive postural control and dynamic gait, predicted changes in gait speed and stride time DTCs. CONCLUSION: The absence of an effect of TKR on gait DTCs can potentially underlie increased fall risk after TKR. Results from this study emphasize the significance of balance as a measure and focal point for rehabilitation after TKR. IMPACT: This study contributes to our understanding of the attentional cost of walking in people before and after TKR, as well as to factors associated with it. Results from this work can assist formulation of rehabilitation programs for people with knee OA.

Reduced gait stability in high-functioning poststroke individuals.

Falls during walking are a major cause of poststroke injury, and walking faster may decrease the ability to recover following a gait perturbation. We compared gait stability between high-functioning poststroke individuals and controls and evaluated the effect of gait speed on gait stability. Ten stroke subjects and ten age-matched controls walked on a self-paced treadmill at two speeds (matched/faster). Movement of the nonparetic/dominant leg was arrested unexpectedly at early swing. Poststroke individuals lowered the perturbed leg following perturbation (58% of cases) while controls maintained the leg elevated (49% of cases; P < 0.01). In poststroke individuals, double-support duration was restored later than in controls (4.6 ± 0.8 vs. 3.2 ± 0.3 strides; P < 0.007), and long-term phase shifts of arm and leg movements were larger and less coordinated on the paretic side. A moderate speed increase (~20%) enhanced the incidence of leg lowering in controls but not in stroke subjects. Faster walkers in both groups had a more coordinated response, limited to the nonparetic side in the stroke group. However, faster walkers were not more stable following perturbation. Our results suggest that gait perturbations can target basic control processes and identify neurological locomotor deficits in individuals with fall risk. Central regulation of body translation in space is involved in recovery of steady-state walking. Impaired descending control (stroke) decreases the ability of the motor system to recover from perturbations and regulate interlimb phase relationships, especially when changing gait speed. However, interlimb coordination may not be a major factor in the recovery of gait stability.

Deficits in intersegmental trunk coordination during walking are related to clinical balance and gait function in chronic stroke.

BACKGROUND AND PURPOSE: Decreased walking speed after stroke may be related to changes in temporal and distance gait factors, endurance, and balance. Functional gait deficits may also be related to changes in coordination, specifically between transverse (yaw) plane trunk movements. Our aim was to determine the relationship between intersegmental coordination during gait and functional gait and balance deficits in individuals with stroke. METHODS: Eleven individuals with chronic stroke and 11 age-matched subjects without disability participated in 2 sessions. In Session 1, clinical evaluations of trunk/limb impairment (Chedoke-McMaster Stroke Assessment), functional gait (Functional Gait Assessment), and balance (BesTest) were performed. In Session 2, gait kinematics during eight 30-second walking trials on a self-paced treadmill at 2 speeds (comfortable and equivalent) were recorded. Equivalence of walking speeds was obtained by asking subjects without disability to walk approximately 20% slower and subjects with stroke to walk approximately 20% faster than their comfortable speed. Thorax and pelvis 3-dimensional angular ranges of motion (ROMs) and intersegmental coordination using the continuous relative phase were analyzed. RESULTS: Comfortable walking speed was slower in subjects with stroke (0.78 m/s) than in subjects without disability (1.22 m/s), despite matched cadences. At both comfortable and equivalent walking speeds (0.97-0.98 m/s), participants with stroke used more thoracic ROM than pelvic transverse ROM in comparison with subjects without disability. Transverse thorax-pelvis coordination was similar between groups when walking speeds were equivalent, but there was more in-phase coordination in participants with stroke walking at their comfortable, slower speed. In subjects with stroke, thoracic ROM and continuous relative phase were correlated with several clinical functional gait and balance measures. DISCUSSION AND CONCLUSION: Changes in segmental transverse ROM and coordination were associated with poor gait and with balance abilities in individuals with stroke. Interventions focusing on recovery of these movement characteristics may lead to better clinical outcomes.

Cognition, Emotion, and Movement in the Context of Rehabilitation.

This Special Issue aims to advance the state of inquiry into the interaction between emotions, cognition, and motor performance and learning [...].

Factors associated with texting and walking performance in children with ADHD: The role of age, environment, and symptom severity.

BACKGROUND: Children with ADHD show deficits in executive function, as well as motor symptoms such as difficulties in gross and fine motor skills and gait stability. Texting while walking is becoming increasingly common and is a significant health risk among people of all ages. RESEARCH QUESTION: The objective of this work was to compare texting and walking performance between children with ADHD and controls and between two environments (indoors and outdoors), and evaluate the role of age and symptom severity in dual-task performance. METHODS: Nineteen children with ADHD and 30 healthy children walked across an indoors corridor and an outdoors street, with and without texting on a mobile phone. Walking and texting performance were measured using inertial measurement units and a custom-made mobile app. RESULTS: No between-group differences were found in texting or walking performance. Walking and texting were similar across environments. In both groups, older children had smaller dual-task performance deficits for both gait and texting speed. Children with ADHD who had more severe symptoms of hyperactivity had larger dual task costs for gait speed outdoors (r = 0.69, p = 0.002), and those with more motor symptoms typed faster under dual-task conditions indoors (r = 0.6, p = 0.007) but were less accurate (r = - 0.60, p = 0.009). SIGNIFICANCE: Children with ADHD do not demonstrate deficits in dual-task performance of a texting and walking task indoors or outdoors. The relationship of age, hyperactivity and motor symptoms with texting and walking performance supports a more personalized approach for examination of dual-task performance in children with ADHD.

Compensatory movement strategies differentially affect attention allocation and gait parameters in persons with Parkinson's disease.

Persons with Parkinson's disease (PwP) are advised to use compensatory strategies such as external cues or cognitive movement strategies to overcome gait disturbances. It is suggested that external cues involve the processing of sensory stimulation, while cognitive-movement strategies use attention allocation. This study aimed to compare over time changes in attention allocation in PwP between prolonged walking with cognitive movement strategy and external cues; to compare the effect of cognitive movement strategies and external cues on gait parameters; and evaluate whether these changes depend on cognitive function. Eleven PwP participated in a single-group pilot study. Participants walked for 10 min under each of three conditions: natural walking, using external cuing, using a cognitive movement strategy. Attention and gait variables were extracted from a single-channel electroencephalogram and accelerometers recordings, respectively. Attention allocation was assessed by the% of Brain Engagement Index (BEI) signals within an attentive engagement range. Cognitive function was assessed using a neuropsychological battery. The walk was divided into 2-min time segments, and the results from each 2-min segment were used to determine the effects of time and condition. Associations between cognitive function and BEI signals were tested. Findings show that in the cognitive movement strategy condition, there was a reduction in the % of BEI signals within the attentive engagement range after the first 2 min of walking. Despite this reduction the BEI did not consistently differ from natural and metronome walking. Spatiotemporal gait variables were better in the cognitive movement strategy condition relative to the other conditions. Global cognitive and information processing scores were significantly associated with the BEI only when the cognitive movement strategy was applied. In conclusion, the study shows that a cognitive movement strategy has positive effects on gait variables but may impose a higher attentional load. Furthermore, when walking using a cognitive movement strategy, persons with higher cognitive function showed elevated attentive engagement. The findings support the idea that cognitive and attentional resources are required for cognitive movement strategies in PwP. Additionally, this study provides support for using single-channel EEG to explore mechanistic aspects of clinical interventions.

Prefrontal Cortex Brain Activation During Texting and Walking: A Functional Near-Infrared Spectroscopy Feasibility Study.

Texting while walking is an increasingly common, potentially dangerous task but its functional brain correlates have yet to be reported. Therefore, we evaluated prefrontal cortex (PFC) activation patterns during single- and dual-task texting and walking in healthy adults. Thirteen participants (29-49 years) walked under single- and dual-task conditions involving mobile phone texting or a serial-7s subtraction task, while measuring PFC activation (functional near-infrared spectroscopy) and behavioral task performance (inertial sensors, mobile application). Head lowering during texting increased PFC activation. Texting further increased PFC activation, and decreased gait performance similarly to serial-7 subtraction. Our results support the key role of executive control in texting while walking.

Postural Control under Cognitive Load: Evidence of Increased Automaticity Revealed by Center-of-Pressure and Head Kinematics.

How postural responses change with sensory perturbations while also performing a cognitive task is still debatable. This study investigated this question via comprehensive assessment of postural sway, head kinematics and their coupling. Twenty-three healthy young adults stood in tandem with eyes open or wearing the HTC Vive Head-Mounted Display (HMD) with a static or dynamic (i.e., movement in the anterior-posterior direction at 5 mm or 32 mm at 0.2 Hz) 3-wall stars display. On half of the trials, participants performed a cognitive serial subtraction task. Medio-lateral center-of-pressure (COP) path significantly increased with the cognitive task, particularly with dynamic visuals whereas medio-lateral variance decreased with the cognitive task. Head path and velocity significantly increased with the cognitive task in both directions while variance decreased. Head-COP cross-correlations ranged between 0.78 and 0.66. These findings, accompanied by frequency analysis, suggest that postural control switched to primarily relying on somatosensory input under challenging cognitive load conditions. Several differences between head and COP suggest that head kinematics contribute an important additional facet of postural control and the relationship between head and COP may depend on task and stance position. The potential of HMDs for clinical assessments of balance needs to be further explored.

Bilateral leg stepping coherence as a predictor of freezing of gait in patients with Parkinson's Disease walking with wearable sensors.

Freezing of Gait (FOG) is among the most debilitating symptoms of Parkinson's Disease (PD), characterized by a sudden inability to generate effective stepping. In preparation for the development of a real-time FOG prediction and intervention device, this work presents a novel FOG prediction algorithm based on detection of altered interlimb coordination of the legs, as measured using two inertial movement sensors and analyzed using a wavelet coherence algorithm. METHODS: Fourteen participants with PD (in OFF state) were asked to walk in challenging conditions (e.g. with turning, dual-task walking, etc.) while wearing inertial motion sensors (waist, 2 shanks) and being videotaped. Occasionally, participants were asked to voluntarily stop (VOL). FOG and VOL events were identified by trained researchers based on videos. Wavelet analysis was performed on shank sagittal velocity signals and a synchronization loss threshold (SLT) was defined and compared between FOG and VOL. A proof-of-concept analysis was performed for a subset of the data to obtain preliminary classification characteristics of the novel measure. RESULTS: 128 FOG and 42 VOL episodes were analyzed. SLT occurred earlier for FOG (MED=1.81 sec prior to stop, IQR=1.57) than for VOL events (MED=0.22 sec, IQR=0.76) (Z=-4.3, p<0.001, ES=1.15). These time differences were not related with measures of disease severity. Preliminary results demonstrate sensitivity of 98%, specificity of 42% (mostly due to 'turns' detection) and balanced accuracy of 70% for SLT-based prediction, with good differentiation between FOG and VOL. CONCLUSIONS: Wavelet analysis provides a relatively simple, promising approach for prediction of FOG in people with PD.