A Network of Sites and Upskilled Therapists to Deliver Best-Practice Stroke Rehabilitation of the Arm: Protocol for a Knowledge Translation Study.

Implementation of evidence-informed rehabilitation of the upper limb is variable, and outcomes for stroke survivors are often suboptimal. We established a national partnership of clinicians, survivors of stroke, researchers, healthcare organizations, and policy makers to facilitate change. The objectives of this study are to increase access to best-evidence rehabilitation of the upper limb and improve outcomes for stroke survivors. This prospective pragmatic, knowledge translation study involves four new specialist therapy centers to deliver best-evidence upper-limb sensory rehabilitation (known as SENSe therapy) for survivors of stroke in the community. A knowledge-transfer intervention will be used to upskill therapists and guide implementation. Specialist centers will deliver SENSe therapy, an effective and recommended therapy, to stroke survivors in the community. Outcomes include number of successful deliveries of SENSe therapy by credentialled therapists; improved somatosensory function for stroke survivors; improved performance in self-selected activities, arm use, and quality of life; treatment fidelity and confidence to deliver therapy; and for future implementation, expert therapist effect and cost-effectiveness. In summary, we will determine the effect of a national partnership to increase access to evidence-based upper-limb sensory rehabilitation following stroke. If effective, this knowledge-transfer intervention could be used to optimize the delivery of other complex, evidence-based rehabilitation interventions.

Characterizing Touch Discrimination Impairment from Pooled Stroke Samples Using the Tactile Discrimination Test: Updated Criteria for Interpretation and Brief Test Version for Use in Clinical Practice Settings.

Somatosensory loss post-stroke is common, with touch sensation characteristically impaired. Yet, quantitative, standardized measures of touch discrimination available for clinical use are currently limited. We aimed to characterize touch impairment and re-establish the criterion of abnormality of the Tactile Discrimination Test (TDT) using pooled data and to determine the sensitivity and specificity of briefer test versions. Baseline data from stroke survivors (n = 207) and older neurologically healthy controls (n = 100) assessed on the TDT was extracted. Scores were re-analyzed to determine an updated criterion of impairment and the ability of brief test versions to detect impairment. Updated scoring using an area score was used to calculate the TDT percent maximum area (PMA) score. Touch impairment was common for the contralesional hand (83%) but also present in the ipsilesional hand (42%). The criterion of abnormality was established as 73.1 PMA across older adults and genders. High sensitivity and specificity were found for briefer versions of the TDT (25 vs. 50 trials; 12 or 15 vs. 25 trials), with sensitivity ranging between 91.8 and 96.4% and specificity between 72.5 and 95.0%. Conclusion: Updated criterion of abnormality and the high sensitivity and specificity of brief test versions support the use of the TDT in clinical practice settings.

Calibration of Impairment Severity to Enable Comparison across Somatosensory Domains.

Comparison across somatosensory domains, important for clinical and scientific goals, requires prior calibration of impairment severity. Provided test score distributions are comparable across domains, valid comparisons of impairment can be made by reference to score locations in the corresponding distributions (percentile rank or standardized scores). However, this is often not the case. Test score distributions for tactile texture discrimination (n = 174), wrist joint proprioception (n = 112), and haptic object identification (n = 98) obtained from pooled samples of stroke survivors in rehabilitation settings were investigated. The distributions showed substantially different forms, undermining comparative calibration via percentile rank or standardized scores. An alternative approach is to establish comparable locations in the psychophysical score ranges spanning performance from just noticeably impaired to maximally impaired. Several simulation studies and a theoretical analysis were conducted to establish the score distributions expected from completely insensate responders for each domain. Estimates of extreme impairment values suggested by theory, simulation and observed samples were consistent. Using these estimates and previously discovered values for impairment thresholds in each test domain, comparable ranges of impairment from just noticeable to extreme impairment were found. These ranges enable the normalization of the three test scales for comparison in clinical and research settings.

The Functional Tactile Object Recognition Test: A Unidimensional Measure With Excellent Internal Consistency for Haptic Sensing of Real Objects After Stroke.

INTRODUCTION: Our hands, with their exquisite sensors, work in concert with our sensing brain to extract sensory attributes of objects as we engage in daily activities. One in two people with stroke experience impaired body sensation, with negative impact on hand use and return to previous valued activities. Valid, quantitative tools are critical to measure somatosensory impairment after stroke. The functional Tactile Object Recognition Test (fTORT) is a quantitative measure of tactile (haptic) object recognition designed to test one's ability to recognize everyday objects across seven sensory attributes using 14 object sets. However, to date, knowledge of the nature of object recognition errors is limited, and the internal consistency of performance across item scores and dimensionality of the measure have not been established. OBJECTIVES: To describe the original development and construction of the test, characterize the distribution and nature of performance errors after stroke, and to evaluate the internal consistency of item scores and dimensionality of the fTORT. METHOD: Data from existing cohorts of stroke survivors (n = 115) who were assessed on the fTORT quantitative measure of sensory performance were extracted and pooled. Item and scale analyses were conducted on the raw item data. The distribution and type of errors were characterized. RESULTS: The 14 item sets of the fTORT form a well-behaved unidimensional scale and demonstrate excellent internal consistency (Cronbach alpha of 0.93). Deletion of any item failed to improve the Cronbach score. Most items displayed a bimodal score distribution, with function and attribute errors (score 0) or correct response (score 3) being most common. A smaller proportion of one- or two-attribute errors occurred. The total score range differentiated performance over a wide range of object recognition impairment. CONCLUSION: Unidimensional scale and similar factor loadings across all items support simple addition of the 14 item scores on the fTORT. Therapists can use the fTORT to quantify impaired tactile object recognition in people with stroke based on the current set of items. New insights on the nature of haptic object recognition impairment after stroke are revealed.

Measures of maximal tactile pressures of a sustained grasp task using a TactArray device have satisfactory reliability and validity in healthy people.

Objective: To investigate the reliability and the concurrent validity of maximal tactile pressures and forces of a sustained grasp task using a TactArray device in healthy adults.Methods: Healthy participants (n = 18, mean age: 62.2 ± 9.9 years) performed three repeat trials of sustained maximal grasp over 8 seconds. Both hands were tested in within-day and between-day sessions, with vision and without vision. Measures of maximal tactile pressures and forces were measured for the complete grasp duration (8s) and for the plateau phase (5s). Measures of maximal tactile pressures and forces were reported using the highest value among three repeat trials, the mean of two repeat trials, and the mean of three repeat trials. Reliability was determined using changes in mean, coefficients of variation and intraclass correlation coefficients (ICCs). Pearson correlation coefficients were used to evaluate concurrent validity.Results: Changes in mean were very good, coefficients of variation were good to acceptable and ICCs were very good to good for maximal tactile pressures using the highest value among three repeat trials and the mean of three repeat trials for the complete grasp duration (8s) and for the plateau phase (5s) in the dominant hand with and without vision and in the non-dominant hand without vision for within-day and between-day sessions. Maximal tactile pressures had moderate to large correlations with grip strength.Conclusion: The TactArray device demonstrates satisfactory reliability for maximal tactile pressures during a sustained grasp for within-day and between-day testing sessions in both hands. Validity was satisfactory with grip strength in both hands.

The effectiveness of somatosensory retraining for improving sensory function in the arm following stroke: a systematic review.

OBJECTIVE: The aim of this study was to evaluate if somatosensory retraining programmes assist people to improve somatosensory discrimination skills and arm functioning after stroke. DATA SOURCES: Nine databases were systematically searched: Medline, Cumulative Index to Nursing and Allied Health Literature, PsychInfo, Embase, Amed, Web of Science, Physiotherapy Evidence Database, OT seeker, and Cochrane Library. REVIEW METHODS: Studies were included for review if they involved (1) adult participants who had somatosensory impairment in the arm after stroke, (2) a programme targeted at retraining somatosensation, (3) a primary measure of somatosensory discrimination skills in the arm, and (4) an intervention study design (e.g. randomized or non-randomized control designs). RESULTS: A total of 6779 articles were screened. Five group trials and five single case experimental designs were included ( N = 199 stroke survivors). Six studies focused exclusively on retraining somatosensation and four studies focused on somatosensation and motor retraining. Standardized somatosensory measures were typically used for tactile, proprioception, and haptic object recognition modalities. Sensory intervention effect sizes ranged from 0.3 to 2.2, with an average effect size of 0.85 across somatosensory modalities. A majority of effect sizes for proprioception and tactile somatosensory domains were greater than 0.5, and all but one of the intervention effect sizes were larger than the control effect sizes, at least as point estimates. Six studies measured motor and/or functional arm outcomes ( n = 89 participants), with narrative analysis suggesting a trend towards improvement in arm use after somatosensory retraining. CONCLUSION: Somatosensory retraining may assist people to regain somatosensory discrimination skills in the arm after stroke.

Initial severity of somatosensory impairment influences response to upper limb sensory retraining post-stroke.

BACKGROUND: Somatosensory loss occurs often following stroke. A proportional recovery model is proposed for spontaneous motor recovery, with implication for treatment planning. It is currently unknown if initial severity of sensory impairment influences stroke survivors' response to treatment to improve sensation. OBJECTIVE: To examine if initial (pre-treatment) severity of upper limb somatosensory impairment is related to sensation outcomes following treatment. METHODS: Regression analysis was used to investigate the relationship between initial and post-treatment sensation performance. Data were pooled from two randomized controlled trials of somatosensory discrimination retraining (N = 80). Upper limb somatosensation was measured using standardized tests of sensory discrimination: Fabric Matching Test, Wrist Position Sense Test, and functional Tactile Object Recognition Test. RESULTS: Post-treatment somatosensory improvement patterns were proportional to the extent of initial pre-treatment somatosensory impairment (Texture discrimination: B = 0.74, 95% CIs [0.52, 0.96]; Proprioception: B = 0.35, 95% CIs [0.24, 0.47]; Object recognition: B = 0.85, 95% CIs [0.75, 0.95]). CONCLUSIONS: The effect of somatosensory retraining on post-treatment sensation was proportional to the extent of upper limb initial somatosensory impairment. Findings suggest sensory retraining can benefit stroke survivors of varying severity of sensory impairment, including those with more severe somatosensory loss.

Effects of Somatosensory Impairment on Participation After Stroke.

OBJECTIVE: Our objective was to determine the effect of loss of body sensation on activity participation in stroke survivors. METHOD: Participants (N = 268) were assessed at hospital admission for somatosensory and motor impairment using the National Institutes of Health Stroke Scale. Participation was assessed using the Activity Card Sort (ACS) in the postacute phase. Between-group differences in activity participation were analyzed for participants with and without somatosensory impairment and with or without paresis. RESULTS: Somatosensory impairment was experienced in 33.6% of the sample and paresis in 42.9%. ACS profiles were obtained at a median of 222 days poststroke. Somatosensory loss alone (z = 1.96, p = .048) and paresis in upper and lower limbs without sensory loss (z = 4.62, p < .001) influenced activity participation. CONCLUSION: Somatosensory impairment is associated with reduced activity participation; however, paresis of upper and lower limbs can mask the contribution of sensory loss.

Change in Functional Arm Use Is Associated With Somatosensory Skills After Sensory Retraining Poststroke.

OBJECTIVE: We investigated changes in functional arm use after retraining for stroke-related somatosensory loss and identified whether such changes are associated with somatosensory discrimination skills. METHOD: Data were pooled (N = 80) from two randomized controlled trials of somatosensory retraining. We used the Motor Activity Log to measure perceived amount of arm use in daily activities and the Action Research Arm Test to measure performance capacity. Somatosensory discrimination skills were measured using standardized modality-specific measures. RESULTS: Participants' arm use improved after somatosensory retraining (z = -6.80, p < .01). Change in arm use was weakly associated with somatosensation (tactile, ß = 0.31, p < .01; proprioception, ß = -0.17, p > .05; object recognition, ß = 0.13, p < .05). CONCLUSION: Change in daily arm use was related to a small amount of variance in somatosensory outcomes. Stroke survivors' functional arm use can increase after somatosensory retraining, with change varying among survivors.

The Right Supramarginal Gyrus Is Important for Proprioception in Healthy and Stroke-Affected Participants: A Functional MRI Study.

Human proprioception is essential for motor control, yet its central processing is still debated. Previous studies of passive movements and illusory vibration have reported inconsistent activation patterns related to proprioception, particularly in high-order sensorimotor cortices. We investigated brain activation specific to proprioception, its laterality, and changes following stroke. Twelve healthy and three stroke-affected individuals with proprioceptive deficits participated. Proprioception was assessed clinically with the Wrist Position Sense Test, and participants underwent functional magnetic resonance imaging scanning. An event-related study design was used, where each proprioceptive stimulus of passive wrist movement was followed by a motor response of mirror -copying with the other wrist. Left (LWP) and right (RWP) wrist proprioception were tested separately. Laterality indices (LIs) were calculated for the main cortical regions activated during proprioception. We found proprioception-related brain activation in high-order sensorimotor cortices in healthy participants especially in the supramarginal gyrus (SMG LWP z = 4.51, RWP z = 4.24) and the dorsal premotor cortex (PMd LWP z = 4.10, RWP z = 3.93). Right hemispheric dominance was observed in the SMG (LI LWP mean 0.41, SD 0.22; RWP 0.29, SD 0.20), and to a lesser degree in the PMd (LI LWP 0.34, SD 0.17; RWP 0.13, SD 0.25). In stroke-affected participants, the main difference in proprioception-related brain activation was reduced laterality in the right SMG. Our findings indicate that the SMG and PMd play a key role in proprioception probably due to their role in spatial processing and motor control, respectively. The findings from stroke--affected individuals suggest that decreased right SMG function may be associated with decreased proprioception. We recommend that clinicians pay particular attention to the assessment and rehabilitation of proprioception following right hemispheric lesions.

Stress reactivity and the Hemodynamic Profile-Compensation Deficit (HP-CD) Model of blood pressure regulation.

Considering the central role of the concept of blood pressure reactivity to explanations of the influence of life stress in the pathogenesis of cardiovascular disease, it is important that the underlying psychophysiological determinants of blood pressure change are elucidated. Empirical evidence is reviewed concerning the utility of the Hemodynamic Profile-Compensation Deficit (HP-CD) Model (Gregg et al., 2002), which draws on physiological theory that explains blood pressure regulation as a dynamic compensatory relation between cardiac output and total peripheral resistance. Core constructs and quantitative features of the Model are explained, accompanied by a focussed review of the Model's application in reactivity studies of stress, lifestyle behaviours, laboratory-to-field generalisability, and personality differences. Although the available studies are relatively few in number, evidence of the Model's utility is promising. Application of the Model in further research could help to elucidate cardiovascular pathogenesis in ways not achievable through the study of blood pressure reactivity alone.

Frequency of discriminative sensory loss in the hand after stroke in a rehabilitation setting.

OBJECTIVE: Somatosensory loss following stroke is common, with negative consequences for functional outcome. However, existing studies typically do not include quantitative measures of discriminative sensibility. The aim of this study was to quantify the proportion of stroke patients presenting with discriminative sensory loss of the hand in the post-acute rehabilitation phase. DESIGN: Prospective cohort study of stroke survivors presenting for rehabilitation. PATIENTS: Fifty-one consecutive patients admitted to a metropolitan rehabilitation centre over a continuous 12-month period who met selection criteria. METHODS: Quantitative measures of touch discrimination and limb position sense, with high re-test reliability, good discriminative test properties and objective criteria of abnormality, were employed. Both upper limbs were tested, in counterbalanced order. RESULTS: Impaired touch discrimination was identified in the hand contralateral to the lesion in 47% of patients, and in the ipsilesional hand in 16%. Forty-nine percent showed impaired limb position sense in the contralesional limb and 20% in the ipsilesional limb. Sixty-seven percent demonstrated impairment of at least one modality in the contralesional limb. Ipsilesional impairment was less severe. CONCLUSION: Discriminative sensory impairment was quantified in the contralesional hand in approximately half of stroke patients presenting for rehabilitation. A clinically significant number also experienced impairment in the ipsilesional "unaffected" hand.

SENSe: Study of the Effectiveness of Neurorehabilitation on Sensation: a randomized controlled trial.

BACKGROUND: Sensory loss is common after stroke, with negative impact on exploration of the immediate environment, hand function, and return to daily activities. OBJECTIVE: To compare the effectiveness of a perceptual-learning based sensory discrimination program versus non-specific exposure to sensory stimuli via passive movements and grasping of common objects. METHODS: The authors conducted a randomized parallel-group controlled trial, with blinding of subjects, clinical assessors, and data analysts. Fifty subjects with impaired texture discrimination, limb position sense, and/or tactile object recognition (>6 weeks, median 48 weeks poststroke) were randomized to receive somatosensory discrimination training (n = 25) or repeated exposure to sensory stimuli (n = 25) in 60-minute sessions for a total of 10 hours. The primary outcome was change in a composite standardized somatosensory deficit (SSD) index following intervention. Follow-up was at 6 weeks and 6 months posttraining. RESULTS: Between-group comparisons revealed a significantly greater improvement in sensory capacity following sensory discrimination training, t(47) = 2.75, P = .004, 1-tailed; mean between-group change = 11.1 SSD; confidence interval 3.0 to 19.2. Improvements were maintained at 6 weeks and 6 months. CONCLUSION: Sensory discrimination training can achieve significant improvements in functional sensory discrimination capacity after stroke. The clinically oriented training achieved transfer of training effects to novel stimuli. Our findings provide support for introducing SENSe discrimination training in rehabilitation of sensory deficits after stroke.

Clinical measures of handgrip limitation relate to impaired pinch grip force control after stroke.

This study examined whether clinical measures of handgrip limitation relate to laboratory measures of grip force impairment during a pinch grip, lift, and hold task post-stroke. Handgrip ability in 45 people with stroke who had residual grip ability was examined relative to 45 age-matched healthy adults. The clinical tests included items from a) the Jebsen Taylor Hand Function Test; b) the Motor Assessment Scale; c) the Functional Independence Measure (FIM); and d) a custom-designed survey about hand-use in daily life. The laboratory test was summarized by principal components: 1) Pre-Lift Delay and 2) Grip Force Dyscontrol. For the stroke group, a moderate to strong correlation was found between Pre-Lift Delay and each clinical measure of handgrip limitation (rs=0.70-0.85) except the FIM (rs=0.38-0.49). In contrast, Grip Force Dyscontrol was not associated with handgrip limitation on any of the clinical tests (rs=-0.08 to 0.18).

Impaired discrimination of surface friction contributes to pinch grip deficit after stroke.

BACKGROUND: Impaired sensation and force production could both contribute to handgrip limitation after stroke. Clinically, training is usually directed to motor impairment rather than sensory impairment despite the prevalence of sensory deficit and the importance of sensory input for grip control. OBJECTIVE: The aim of this study was to investigate if sensory deficits contribute to pinch grip dysfunction beyond that attributable to motor deficits poststroke. METHODS: The study enlisted 45 stroke participants and 45 healthy controls matched for age, gender, and hand dominance. Ability to differentiate surface friction (Friction Discrimination Test [FDT]), match object weight (Weight Matching Test [WMT]), produce grip force to track a visual target (Visually Guided Pinch Test [VGPT]), and perform a Pinch-Grip Lift-and-Hold Test (PGLHT) was quantified relative to normative performance, as defined by matched controls. The relationship between sensory ability (FDT, WMT) and altered PGLHT performance adjusted for motor ability (VGPT) after stroke was then examined using multivariate regression. RESULTS: Deficits in FDT, WMT, and VGPT ability were present in at least half of the stroke sample and were largely independent across the variables. Poorer friction discrimination was significantly associated with longer latencies of grip-lift (r = .34; P = .03) and grip force dysregulation (r= .34; P= .03) after the impact of VGPT was statistically removed from PGLHT ability. However, performance on WMT did not relate to either PGLHT deficit. CONCLUSION: The findings indicate that impaired friction discrimination ability contributes to altered timing and force adjustment during PGLHT poststroke.

Short-term relationships between footstep variables in young adults.

Autocorrelation analyses were used to quantify the short-term relationships between selected footstep variables during steady state, straight-line over-ground walking in 20 healthy young adults. The serial dependency for step length, step time, heel to heel base of support (HHBS) and double limb support time were examined for a minimum of six consecutive steps using an 8.3m GAITRite analysis system. As well as investigating the dependence of data obtained from consecutive steps (lag 1) and between steps of consecutive strides (lag 2), cross correlation analyses were used to explore the relationships between step length and HHBS. The results showed serial dependency from one step to the next for step length and step time, whereas HHBS and double limb support duration showed stride-to-stride autocorrelations. Cross correlational analyses did not reveal a relationship between stride length and HHBS, suggesting independence between these variables.

Grip force regulation during pinch grip lifts under somatosensory guidance: comparison between people with stroke and healthy controls.

OBJECTIVES: To compare the timing and grip force application in a pinch grip task performed under somatosensory guidance in stroke and matched controls and to identify characteristics of impaired grip force regulation after stroke. DESIGN: Matched-pairs control group. SETTING: University research laboratory. PARTICIPANTS: Forty-five people with stroke who could pick up a pen lid using a pinch grip and actively participated in rehabilitation and 45 adults without neurologic conditions or musculoskeletal or skin impairments affecting the hand, matched for age, sex, and hand dominance. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Timing and magnitude of grip forces applied during pinch grip lift and hold. RESULTS: Prolonged time to grip and lift objects, and excessive grip force prior to commencing the lift occurred in approximately half of the contralesional (involved) hands of people with stroke. Fluctuating irregular forces and reduced adaptation of the grip safety margin were also observed. Excessive safety margins were not predominant after stroke. Extreme slowing and disorganized sequencing of the grip and lifting forces and difficulty maintaining a stable grip characterized severe dysfunction. CONCLUSIONS: Delayed grip formulation and variable grip force application are key characteristics of grip dysfunction after stroke.

Association between hemodynamic profile during laboratory stress and ambulatory pulse pressure.

Hemodynamic responses underlying blood pressure reactivity to laboratory stress are theoretically linked to cardiovascular pathophysiology. The present study investigated whether a vascular response predicted ambulatory pulse pressure, a known risk factor for cardiovascular disease. A new model of hemodynamic profile, previously developed by the authors, was applied to 24-h ambulatory data from 30 female and 34 male healthy young adults. Of these, 40 were monitored during a naturalistic stressor (university examination). For females, hemodynamic profile significantly predicted nighttime systolic blood pressure, and 24-h, day-, and nighttime diastolic blood pressure, but not ambulatory pulse pressure. A vascular or mixed hemodynamic profile significantly predicted 24-h and daytime ambulatory pulse pressure in males. The findings are consistent with theories of pathogenic mechanisms involving vascular changes and suggest that, for males, a vascular or mixed hemodynamic profile measured during laboratory stress may be a risk marker for cardiovascular disease, by its association with ambulatory pulse pressure.

Training of somatosensory discrimination after stroke: facilitation of stimulus generalization.

OBJECTIVE: Task-specific learning typifies perceptual training but limits rehabilitation of sensory deficit after stroke. We therefore investigated spontaneous and procedurally facilitated transfer of training effects within the somatosensory domain after stroke. DESIGN: Ten single-case, multiple-baseline experiments were conducted with stroke participants who had impaired discrimination of touch or limb-position sense. Each experiment comprised three phases: baseline, stimulus-specific training of the primary discrimination stimulus, and either stimulus-specific training of the transfer stimulus or stimulus-generalization training. Both the trained and transfer stimuli were monitored throughout using quantitative, norm-referenced measures. Data were analyzed using individual time-series analysis and meta-analysis of intervention effects across case experiments. RESULTS: Stimulus-specific training was successful for trained texture and proprioceptive discriminations, but it failed to show spontaneous transfer to related untrained stimuli in the same modality in seven of eight experiments in which this was possible. In contrast, intramodality transfer was obtained with stimulus-generalization training in four of five experiments that investigated stimulus-generalization training of texture discrimination. Findings were confirmed by meta-analysis. CONCLUSIONS: Our findings demonstrate generalization of training within a somatosensory modality poststroke, provided that a program designed to enhance transfer is used. This has implications for the design of efficient rehabilitation programs.