Machine learning for automating subjective clinical assessment of gait impairment in people with acquired brain injury - a comparison of an image extraction and classification system to expert scoring.

BACKGROUND: Walking impairment is a common disability post acquired brain injury (ABI), with visually evident arm movement abnormality identified as negatively impacting a multitude of psychological factors. The International Classification of Functioning, Disability and Health (ICF) qualifiers scale has been used to subjectively assess arm movement abnormality, showing strong intra-rater and test-retest reliability, however, only moderate inter-rater reliability. This impacts clinical utility, limiting its use as a measurement tool. To both automate the analysis and overcome these errors, the primary aim of this study was to evaluate the ability of a novel two-level machine learning model to assess arm movement abnormality during walking in people with ABI. METHODS: Frontal plane gait videos were used to train four networks with 50%, 75%, 90%, and 100% of participants (ABI: n = 42, healthy controls: n = 34) to automatically identify anatomical landmarks using DeepLabCut™ and calculate two-dimensional kinematic joint angles. Assessment scores from three experienced neurorehabilitation clinicians were used with these joint angles to train random forest networks with nested cross-validation to predict assessor scores for all videos. Agreement between unseen participant (i.e. test group participants that were not used to train the model) predictions and each individual assessor's scores were compared using quadratic weighted kappa. One sample t-tests (to determine over/underprediction against clinician ratings) and one-way ANOVA (to determine differences between networks) were applied to the four networks. RESULTS: The machine learning predictions have similar agreement to experienced human assessors, with no statistically significant (p < 0.05) difference for any match contingency. There was no statistically significant difference between the predictions from the four networks (F = 0.119; p = 0.949). The four networks did however under-predict scores with small effect sizes (p range = 0.007 to 0.040; Cohen's d range = 0.156 to 0.217). CONCLUSIONS: This study demonstrated that machine learning can perform similarly to experienced clinicians when subjectively assessing arm movement abnormality in people with ABI. The relatively small sample size may have resulted in under-prediction of some scores, albeit with small effect sizes. Studies with larger sample sizes that objectively and automatically assess dynamic movement in both local and telerehabilitation assessments, for example using smartphones and edge-based machine learning, to reduce measurement error and healthcare access inequality are needed.

Squamous cell carcinoma of the nail in patients with Fitzpatrick phototypes IV-VI: a systematic review.

Squamous cell carcinoma of the nail unit (nSCC) is a rare malignant tumor of the hand and nail. Although skin cancer rarely affects individuals with phototypes IV-VI, its occurrence in these groups is often associated with greater morbidity and mortality. This study aims to characterize the clinical symptoms, presentations, and treatments of nSCC in patients with darker skin types. A systematic review of PubMed and Embase was performed in May 2023 for all peer-reviewed, English-language nSCC studies involving individuals with Fitzpatrick types IV-VI. Most tumors were located on the fingernails (84%), with the right third finger being the most frequently affected (31%). The nail bed (67%) exhibited a higher prevalence than the lateral/proximal nail folds (33%). The duration of symptoms before diagnosis ranged from 1 month to 7 years. nSCC was most commonly treated with Mohs surgery (38%), followed by amputation (35%). Our study was limited to case reports because of a lack of large nSCC studies that provide information on race or images of each patient. These tumors are generally slow-growing yet often misdiagnosed, leading to delays in presentation and diagnosis. Increased awareness about nSCC in phototype IV-VI individuals will reduce misdiagnoses, unnecessary treatment, and recurrences.

Clinimetric evaluation of five clinically feasible measures of the leg extensor muscle strength in neurological rehabilitation settings.

A gold-standard clinical measure of leg muscle strength has not been established. Therefore, the aim of this study was to evaluate clinimetric properties of five clinically feasible measures of lower-limb extensor muscle strength in neurological rehabilitation settings. This was a cross-sectional observational study of 36 participants with leg weakness as a result of a neurological condition/injury. Participants were recruited across a range of walking abilities, from non- to independently ambulant. Each was assessed using each of the following five measures: manual muscle test (MMT), hand-held dynamometry (HHD), seated single leg press one repetition maximum (1RM), functional sit-to-stand (STS) test and seated single leg press measured with a load cell. Each clinical measure was evaluated for its discriminative ability, floor/ceiling effects, test-retest reliability and clinical utility. The load cell and HHD were the most discriminative of the tests and were also resistant to floor/ceiling effects; however, the load cell was superior to the HHD when compared for its clinical utility. The MMT/STS tests received perfect scores for clinical utility, although similar to the 1RM test, they were susceptible to floor and ceiling effects. The load cell leg press test was the only measure of lower limb strength to satisfy all four clinimetric properties. Implications for clinical practice include, firstly, that strength tests available to clinicians vary in their clinimetric properties. Secondly, the functional status of the person will determine selection of the best clinical strength test. And lastly, load cell device technology should be considered for clinical strength assessments.

Factors Associated With Physical Therapy Engagement During the Period of Posttraumatic Amnesia.

BACKGROUND AND PURPOSE: Physical therapy is important in the management of traumatic brain injury (TBI) and associated multitrauma. Providing therapy during the posttraumatic amnesia (PTA) phase is challenging, given that hallmark features including confusion, amnesia, agitation, and fatigue may impede the person's ability to engage in and benefit from rehabilitation. To date, there is little empirical evidence to guide the provision of therapy during PTA. This observational study aimed to explore the frequency, duration, location, and engagement of physical therapy provision during PTA and the impact of cognition, agitation, and fatigue. SUMMARY OF KEY POINTS: The majority of patients were found to meaningfully engage and participate in physical therapy for the majority of sessions. Only a small proportion were unable to participate in physical therapy. Patient refusal and fatigue were identified as the most prominent barriers to rehabilitation. Despite fatigue and agitation reaching clinical levels, therapy could still successfully proceed on most occasions. RECOMMENDATIONS FOR CLINICAL PRACTICE: Physical therapy is feasible during the acute recovery stages after TBI. Current results support the notion that therapy should commence early to minimize secondary complications and promote the recovery of mobility. A patient-centered therapeutic model that tailors the therapeutic approach to meet the individual's current physical and fluctuating cognitive capabilities may be most suited for this population. Clinicians working with people after TBI need experience in understanding and managing the cognitive limitations and associated symptoms of PTA to optimize the provision of therapy. These findings could inform guidelines for the management of patients in PTA.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A368).

Potential contributing factors to upper limb associated reactions in people with acquired brain injury: an exploratory study.

PURPOSE: To determine which potential contributing factors are associated with upper limb associated reaction (AR) expression in individuals with acquired brain injury (ABI). METHODS: Forty-two participants underwent three-dimensional motion analysis at self-selected walking speed to generate the AR outcome measure, quantifying their upper limb kinematic deviation compared to healthy controls. Clinical assessment included: upper and lower limb hypertonicity, spasticity and strength, balance, dynamic walking stability, arm and leg function, anxiety, arm pain/discomfort, and fear of falling. RESULTS: Significant, moderate-to-strong correlations (r = 0.42-0.74, p < 0.05) existed between upper limb ARs and both hypertonicity and spasticity of the upper limb muscles and the knee extensors. Significant, moderate correlations to ARs (r = 0.42-0.59, p < 0.05) existed for balance, dynamic stability, upper limb strength, and arm function. The severity of AR was significantly different between those with and without hypertonicity of the four tested upper limb muscles, elbow and long finger flexor spasticity, knee extensor spasticity, and reduced dynamic stability (p < 0.05; effect sizes ≥0.80). However, these contributing factors were not present in all participants. CONCLUSIONS: Associated reactions are complex and multi-factorial. There were several significant correlations indicating that factors may influence AR severity. While positive upper motor neuron syndrome features should be prioritised for clinical assessment, these factors are not prerequisites for ARs.IMPLICATIONS FOR REHABILITATIONUpper limb associated reactions are a complex and multi-factorial phenomenon.Upper limb muscle hypertonicity and spasticity should be prioritised for assessment; however, they are not prerequisites for associated reactions.Hypertonicity and spasticity should be differentiated as they may have differing relationships to associated reactions.Knee extensor hypertonicity and spasticity, postural stability, upper limb strength, and arm function may also be contributing factors to consider.

Assessment of upper limb abnormalities using the Kinect: Reliability, validity and detection accuracy in people living with acquired brain injury.

Upper limb kinematic abnormalities are prevalent in people with acquired brain injury (ABI). We examined if the Microsoft Kinect for Xbox One (Kinect) reliably (test-retest) and validly (concurrent) quantifies upper limb kinematics, and accurately classifies abnormalities (sensitivity/specificity), in an ABI cohort when compared to three-dimensional motion analysis (3DMA) and a subjective rating scale. We compared 42 adults with ABI to 36 healthy control (HC) participants. Walking trials were recorded by 3DMA and Kinect at self-selected (SSWS) and fast (FWS) walking speeds. When classifying abnormalities for 3DMA and Kinect, a 95% reference range (based on HC data) was calculated using the Kinematic Deviation Score worst axis (KDSw); values outside of this range were classified abnormal. Scores ≥ 2 in the subjective rating scale, based on International Classification of Functioning, Disability and Health Framework's Qualifiers Scale, were considered abnormal. Test-retest reliability and concurrent validity were determined using intra-class correlation coefficient (Absolute ICC2,1) and Pearson's or Spearman's correlation respectively. Fisher's Exact Test was conducted to determine sensitivity and specificity between each combination of the two methods. Strong test-retest reliability was observed for 3DMA (median(IQR) ICC:0.86(0.85-0.90)). Kinect showed overall strong SSWS test-retest reliability (ICC:0.87(0.84-0.91)) and moderate FWS test-retest reliability (ICC:0.61(0.56-0.65)). Concurrent validity between 3DMA and Kinect was overall moderate. Sensitivity and specificity between 3DMA, Kinect and subjective scores were overall modest. Our results suggest caution should be used if implementing Kinect as its validity is modest against criterion-reference 3DMA; however, given its reliability and similar sensitivity/specificity to 3DMA further responsiveness research is warranted.

Upper Limb Associated Reactions: The Relationship Between Movement Kinematics and Muscle Activity in Seated Versus Walking Testing.

OBJECTIVE: The aims of this study were to (1) evaluate the relationships between stationary and dynamic associated reaction (AR) tests in people with acquired brain injury using surface electromyography (sEMG) muscle activity and three-dimensional motion analysis kinematic measures and (2) assess the test-retest reliability of sEMG and seated tests of ARs. DESIGN: Forty-two adults with acquired brain injury underwent AR testing with seated contralateral maximal voluntary isometric contraction tests and walking (self-selected and fast speeds). Associated reaction measurements included biceps brachii sEMG, elbow goniometry, and three-dimensional motion analysis kinematics during walking. Pearson correlations evaluated the relationships between seated and dynamic walking AR tests and between muscle activity and kinematic measures. Chronic participants were reassessed 1 wk later for reliability. RESULTS: A strong (r = 0.65) and moderate (r = 0.53) relationship existed for biceps brachii sEMG during seated and walking tests at self-selected and fast walk, respectively. A weak to moderate relationship existed between biceps brachii sEMG and kinematics during walking and between seated and walking measures of ARs (r = 0.23-0.53). All tests had strong to very strong test-retest reliability (intraclass correlation coefficients, >0.78). CONCLUSION: Seated contralateral maximal voluntary isometric contraction tests correlate only weakly to moderately with AR walking kinematics and moderately to strongly with biceps brachii activation during walking. Moderate relationships exist between sEMG and kinematics, indicating that they may provide different information for ARs.

Factors Affecting Participation in Physical Therapy During Posttraumatic Amnesia.

OBJECTIVES: To examine the effect of agitation, cognitive impairment, fatigue, and pain on physical therapy participation and outcomes during posttraumatic amnesia (PTA) after traumatic brain injury (TBI). DESIGN: Prospective longitudinal study. SETTING: Inpatient rehabilitation hospital. PARTICIPANTS: Participants (N=77) with moderate-to-severe TBI who were deemed to be experiencing PTA using the Westmead Post-Traumatic Amnesia Scale. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Pittsburgh Rehabilitation Participation Scale and time in therapy (min) were recorded twice daily after routine physical therapy sessions during PTA. The FIM-motor (select items related to physical therapy) score rated on admission and after emergence from PTA was used to calculate FIM-motor change. RESULTS: Agitation was associated with lower participation in therapy. The presence of agitation and pain both predicted lower FIM-motor change at emergence from PTA. Higher levels of cognitive impairment and fatigue were also associated with lower participation and less time in therapy. CONCLUSIONS: The presence of agitation, fatigue, pain, and cognitive impairment impede rehabilitation success during PTA. This study strengthens the case for implementing environmental and behavioral recommendations, such as conducting therapy earlier in the day within a familiar space (ie, on the ward) and tailoring session duration to patient needs. This is with the aim of minimizing fatigue, agitation, and pain, while promoting cognitive recovery and arousal during PTA to maximize physical gains. Further research is warranted to examine the factors associated with rehabilitation success across other therapeutic disciplines.

Quantification of abnormal upper limb movement during walking in people with acquired brain injury.

BACKGROUND: Abnormal upper limb movements frequently affect people with acquired brain injury (ABI) during walking. Three-dimensional motion analysis (3DMA) can quantify upper limb abnormality kinematically, with composite scores condensing multiple joint axes data into a single score. RESEARCH QUESTION: Are 3DMA-derived composite scores valid (known-groups and convergent validity), reliable and able to quantify speed-related changes in abnormal upper limb movement during walking? METHODS: This observational study compared 42 adults with ABI and abnormal upper limb movements during walking with 36 healthy controls (HC) at a matched walking speed intention. Participants underwent 3DMA assessment of self-selected and fast walking speeds. Composite scores quantified the affected upper limb's kinematic abnormality. The Arm Posture Score arithmetic mean version (APSam) and 1.96 standard deviation reference-range scaled versions; the Kinematic Deviation Score mean (KDSm) and worst score (KDSw) were evaluated for association with each other and subjective abnormality rating (Pearson's 'r' correlation), test-retest reliability (intra-class correlation coefficient (ICC)), and ability to quantify speed-related changes in abnormal upper limb movement (Cohen's d effect size (ES), % change scores). RESULTS: Very strong correlations existed between composite scores. The KDSm under-classified upper limb abnormality, whereas the KDSw captured the majority of ABI participants. All scores had moderate-strong correlations with subjective rating of abnormal upper limb movements (r = 0.54 - 0.79) and very strong test-retest reliability (ICCs > 0.81). The APSam demonstrated a 16% (ES = 0.76) walking speed-related increase in upper limb abnormality, whilst decreases were demonstrated in the KDSm 26% (ES 0.90) and KDSw 35% (ES 0.96). SIGNIFICANCE: The APSam, KDSw, and number of abnormal joint axes comprehensively assess the whole upper limb abnormal movements, accurately classifies abnormality, and quantifies severity. This study illustrated notable presence of abnormal upper limb movements at self-selected walking speed and small increase at fast speeds. However, when scaled to HC variability, the fast walk kinematics became less abnormal due to increased HC movement variability.

The reproducibility and responsiveness of subjective assessment of upper limb associated reactions in people with acquired brain injury during walking.

OBJECTIVE: The aim of this study is to determine inter-rater, test-retest and intra-rater reproducibility and responsiveness of subjective assessment of upper limb associated reactions in people with acquired brain injury using (1) the 'Qualifiers Scale' of the International Classification of Functioning, Disability and Health Framework, and (2) visually estimated elbow flexion angle during walking. DESIGN: Observational study. SETTING: A brain injury rehabilitation centre, Melbourne, Australia. SUBJECTS: People with acquired brain injury and upper limb associated reactions and experienced neurological physiotherapists. MAIN MEASURES: The Qualifiers Scale applied to individual upper limb joints and global associated reaction on a 5-point scale (0-4), a summed upper limb severity score and visually estimated elbow flexion angle. RESULTS: A total of 42 people with acquired brain injury (mean age: 48.4 ± 16.5 years) were videoed walking at self-selected and fast speeds. A subset of 30 chronic brain injury participants (mean time post injury: 8.2 ± 9.3 years) were reassessed one week later for retest reproducibility. Three experienced neurological physiotherapists (mean experience: 22.7 ± 9.1 years) viewed these videos and subjectively rated the upper limb associated reactions. Strong-to-very strong test-retest, intra- and inter-rater reproducibility was found for elbow flexion angle (ICC > 0.86) and the Qualifiers Scale applied to global and individual upper limb joints (ICC > 0.60). Responsiveness of change from self-selected to fast walking speed (mean increase 0.46 m/s) was highest for elbow flexion angle (effect size = 0.83) and low-to-moderate for the Qualifiers Scale. CONCLUSION: Subjectively rated associated reactions during walking demonstrated strong reproducibility and moderate responsiveness to speed change. The Qualifiers Scale and elbow flexion angle can both subjectively quantify associated reactions during walking in a clinical setting.

The nature and extent of upper limb associated reactions during walking in people with acquired brain injury.

BACKGROUND: Upper limb associated reactions (ARs) are common in people with acquired brain injury (ABI). Despite this, there is no gold-standard outcome measure and no kinematic description of this movement disorder. The aim of this study was to determine the upper limb kinematic variables most frequently affected by ARs in people with ABI compared with a healthy cohort at matched walking speed intention. METHODS: A convenience sample of 36 healthy control adults (HCs) and 42 people with ABI who had upper limb ARs during walking were recruited and underwent assessment of their self-selected walking speed using the criterion-reference three dimensional motion analysis (3DMA) at Epworth Hospital, Melbourne. Shoulder flexion, abduction and rotation, elbow flexion, forearm rotation and wrist flexion were assessed. The mean angle, standard deviation (SD), peak joint angles and total joint angle range of motion (ROM) were calculated for each axis across the gait cycle. On a group level, ANCOVA was used to assess the between-group differences for each upper limb kinematic outcome variable. To quantify abnormality prevalence on an individual participant level, the percentage of ABI participants that were outside of the 95% confidence interval of the HC sample for each variable were calculated. RESULTS: There were significant between-group differences for all elbow and shoulder abduction outcome variables (p < 0.01), most shoulder flexion variables (except for shoulder extension peak), forearm rotation SD and ROM and for wrist flexion ROM. Elbow flexion and shoulder abduction were the axes most frequently affected by ARs. Despite the elbow being the most prevalently affected (38/42, 90%), a large proportion of participants had abnormality, defined as ±1.96 SD of the HC mean, present at the shoulder (32/42, 76%), forearm (20/42, 48%) and wrist joints (10/42, 24%). CONCLUSION: This study provides valuable information on ARs, and highlights the need for clinical assessment of ARs to include all of the major joints of the upper limb. This may inform the development of a criterion-reference outcome measure or classification system specific to ARs.

Toward Accurate Clinical Spasticity Assessment: Validation of Movement Speed and Joint Angle Assessments Using Smartphones and Camera Tracking.

OBJECTIVE: To investigate whether a three-dimensional (3-D) camera (Microsoft Kinect) and a smartphone can be used to accurately quantify the joint angular velocity and range of motion (ROM) compared to a criterion-standard 3-D motion analysis system during a lower limb spasticity assessment. DESIGN: Observational, criterion-standard comparison study. SETTING: Large rehabilitation center. PARTICIPANTS: A convenience sample of 35 controls, 35 patients with a neurologic condition, and 34 rehabilitation professionals (physiotherapists and rehabilitation doctors) participated (N=104). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Modified Tardieu Scale was used to assess spasticity of the quadriceps, hamstrings, soleus, and gastrocnemius. Data for each trial were collected concurrently using the criterion-standard Optitrack 3-D motion analysis (3DMA) system, Microsoft Kinect, and a smartphone. Each healthy control participant was assessed by 1 health professional and each patient with a neurological condition was assessed by 3 health professionals. Spearman correlation coefficient and intraclass correlation coefficient with 95% confidence intervals were used to report the strength of the relationships investigated. RESULTS: The smartphone and Microsoft Kinect demonstrated excellent concurrent validity with the 3DMA system. Overall, 74.8% of the relationships investigated demonstrated a very strong (≥0.80) correlation across all of the testing parameters. The Microsoft Kinect was superior to the smartphone for measuring joint start and end angle, the smartphone was superior for measuring joint angular velocity, and the 2 systems were comparable for measuring total joint ROM. CONCLUSIONS: These findings provide preliminary evidence that user-friendly, low-cost technologies can be used to facilitate accurate measurements of joint angular velocity and angles during a lower limb spasticity assessment in a clinical setting.

Lower limb angular velocity during walking at various speeds.

BACKGROUND: Although it is well established that lower limb joint angles adapt to walking at various speeds, limited research has examined the modifications in joint angular velocity. There is currently no normative dataset for joint angular velocity during walking, which would be useful to allow comparisons for patient cohorts. Additionally, understanding normal joint angular velocity may assist clinical assessment and treatment procedures to incorporate methods that replicate the movement speed of the lower limb joints during walking. RESEARCH QUESTION: This study aimed to examine lower limb joint angles and angular velocities in a healthy population walking at various gait speeds. METHODS: Thirty-six healthy adult participants underwent three-dimensional gait analysis while walking at various speeds during habitual and slowed walking. The peak joint angles and angular velocities during important phases of the gait cycle were examined for the hip, knee and ankle in the sagittal plane. Data were grouped in 0.2 m/s increments from a walking speed of 0.4 m/s to 1.6 m/s to represent the range of walking speeds reported in studies of people with gait impairments. RESULTS: For joint angles and angular velocities, the shape of the gait traces were consistent regardless of the walking speed. However as walking speed increased, so did the peak joint angles and angular velocities for the hip, knee and ankle. The largest angular velocity occurred when the knee joint extended at the terminal swing phase of gait. For the ankle and hip joints, the largest angular velocity occurred during the push-off phase. SIGNIFICANCE: This study examined how lower limb joint angular velocities change with various walking speeds. These data can be used as a comparator for data from clinical cohorts, and has the potential to be used to match clinical assessment and treatment methods to joint angular velocity during walking.

Methods of assessing associated reactions of the upper limb in stroke and traumatic brain injury: A systematic review.

OBJECTIVE: To determine the assessment methods for upper limb (UL) associated reactions (ARs) in people with acquired brain injury (ABI). METHODS: A systematic search of 10 databases was performed for Stage 1 to identify methods that quantify ARs of the hemiplegic UL. Stage 2 searched four databases to examine the clinimetric properties and clinical utility of these methods. Two independent reviewers identified relevant articles, extracted data, assessed study methodological quality and rated the clinimetric properties and clinical utility. RESULTS: Eighteen articles were included. The methods used to evaluate ARs were surface electromyography (11), goniometry (5), dynamometry (5), electrogoniometry (1), subjective clinician (2) and patient rating forms (2). Electromyography, electrogoniometry and dynamometry implemented stationary, seated positions using maximal voluntary contractions of the less impaired UL as the provocative task. Standard goniometry most frequently tested ARs dynamically, using a mobility task to provoke the AR. There was limited clinimetric data available. Only half of the assessment methods were deemed clinically feasible. The most common methods were laboratory-based. CONCLUSION: There were a limited number of methods used to assess ARs in people with ABI and the measurement properties of these outcomes were largely unreported. No gold standard was identified.

Clinical tests of ankle plantarflexor strength do not predict ankle power generation during walking.

OBJECTIVE: The aim of this study was to investigate the relationship between a clinical test of ankle plantarflexor strength and ankle power generation (APG) at push-off during walking. DESIGN: This is a prospective cross-sectional study of 102 patients with traumatic brain injury. OUTCOME MEASURES: Handheld dynamometry was used to measure ankle plantarflexor strength. Three-dimensional gait analysis was performed to quantify ankle power generation at push-off during walking. RESULTS: Ankle plantarflexor strength was only moderately correlated with ankle power generation at push-off (r = 0.43, P < 0.001; 95% confidence interval, 0.26-0.58). There was also a moderate correlation between ankle plantarflexor strength and self-selected walking velocity (r = 0.32, P = 0.002; 95% confidence interval, 0.13-0.48). CONCLUSIONS: Handheld dynamometry measures of ankle plantarflexor strength are only moderately correlated with ankle power generation during walking. This clinical test of ankle plantarflexor strength is a poor predictor of calf muscle function during gait in people with traumatic brain injury.

Strength training for walking in neurologic rehabilitation is not task specific: a focused review.

The aim of this systematic review was to investigate the task specificity of strength training programs for walking in neurologic rehabilitation. Nine electronic databases were searched from conception to October 2012 for randomized controlled trials that used strength training to improve walking in adult neurologic populations. The search identified 25 randomized controlled trials that investigated the efficacy of strength training to improve walking in people with a variety of neurologic conditions. The results revealed that despite significant strength gains, many studies failed to show a significant improvement in walking capacity. Most studies did not include exercises relating to all three main power events important for walking. Strength testing and strengthening exercises were prioritized for the knee extensors and flexors, despite their relatively minor role in human walking. Strengthening exercises performed in the neurologic population are not specific to the main muscle groups responsible for the power generation required for walking. There is a predisposition for strength testing and strengthening exercises to focus on the knee flexors and extensors despite their relatively minor role during walking. Further consideration of the specificity of strength training may provide greater translation of strength gains to improved walking outcomes.

Assessment of the internal construct validity of the revised High-Level Mobility Assessment Tool for traumatic orthopaedic injuries.

OBJECTIVE: To determine whether the revised High-Level Mobility Assessment Tool (HiMAT) was valid for measuring mobility for people with multi-trauma orthopaedic lower limb injuries. DESIGN: Cross-sectional study. SUBJECTS: Participants with lower limb multi-trauma orthopaedic injuries. METHODS: One complete revised HiMAT was obtained for 106 people within 12 weeks of being allowed to fully weight bear. Rasch analysis was used to assess the overall fit of the model for individuals and items, differential item functioning, local dependency, targeting of items and dimensionality. RESULTS: The mean revised HiMAT score was 10.5 (SD = 6.8) with a range of 5-30. Rasch analysis of revised HiMAT showed adequate overall fit to the model (P = 0.29) with no misfitting items (fit residual SD = 0.69) or persons (fit residual SD = 0.62). The scale showed good internal consistency (Person Separation Index = 0.91). One item (hopping) demonstrated disordered thresholds, however this item had good fit to the model in all other aspects. The revised HiMAT was unidimensional, and no differential item functioning was detected for gender or age. The revised HiMAT was well targeted for this group with a range of items across all ability levels. CONCLUSION: The results of this study support the internal construct validity of the revised HiMAT as a well-targeted, unidimensional measure of high-level mobility with no ceiling or floor effect for males and females recovering from multi-trauma orthopaedic lower limb injuries.

The concurrent validity and responsiveness of the high-level mobility assessment tool for mobility limitations in people with multitrauma orthopedic injuries.

OBJECTIVE: To investigate the concurrent validity, responsiveness, and ceiling effect of the revised High-Level Mobility Assessment Tool (HiMAT) in persons after orthopedic multitrauma. DESIGN: Cross-sectional sample of convenience. SETTING: A large tertiary rehabilitation hospital. PARTICIPANTS: Forty-three participants with orthopedic multitrauma lower limb injuries that resulted from motor vehicle accidents. METHODS: This study compared the concurrent validity, responsiveness, and ceiling effects of the revised HiMAT, motor subsection of the Functional Independence Measure (FIM) instrument. Performances for all participants were concurrently scored on the motor FIM, revised HiMAT, and the Lower Extremity Functional Scale (LEFS) at initial testing, and 6 and 12 weeks after the decision to fully bear weight. MAIN OUTCOME MEASUREMENTS: Revised HiMAT, motor FIM, and LEFS. RESULTS: The correlation between the revised HiMAT and the motor FIM was moderate (r = 0.49; P <.001) and partly induced by a ceiling effect in the motor FIM. After 12 weeks of full weight bearing, 51.2% of participants achieved the maximum score on the motor FIM. The correlation between the revised HiMAT and LEFS was weak (r = 0.39; P = .012), which indicated a weak relationship between self-reported mobility problems and actual performance. The revised HiMAT was more responsive than the motor FIM and the LEFS, based on the proportion of persons who exceeded the minimal detectable change score over a period of 6 and 12 weeks. CONCLUSION: The revised HiMAT is more responsive to change than the LEFS and motor FIM, and less susceptible to a ceiling effect than the motor FIM for persons with orthopedic multitrauma. It has poor-to-moderate concurrent validity with the LEFS and motor FIM, which suggests that it may be measuring a different aspect of mobility.

Expression of the p75 TNF receptor is linked to TNF-induced NFkappaB translocation and oxyradical neutralization in glial cells.

Tumor necrosis factor (TNF)-family cytokines induce reactive oxygen species (ROS) that injure vulnerable populations of brain cells. Among glia, oligodendrocytes are particularly susceptible to TNF-induced ROS whereas microglia are protected. We previously found that oligodendrocytes in vitro predominantly express the p55 type-1 TNF receptor, while microglial cells express both type-1 and p75 type-2 receptors. We hypothesized that differential TNF receptor expression and attendant signaling underlies the relative vulnerability of oligodendrocytes, versus microglia, to TNF-induced injury. To test this hypothesis, purified cultures of glial cells were incubated 0-48 hr with TNFalpha or lymphotoxin-alpha, following which levels of ROS, glutathione (GSH), nuclear factor kappa-B (NFkappaB) translocation, and anti-oxidant proteins and activity were measured. 48 hr exposure to TNF increased ROS levels 28% and decreased GSH levels 17% in oligodendrocytes, but decreased levels ROS levels 24% and increased GSH levels 112% increase in microglia. Thirty to 180 min exposure to TNF increased NFkappaB nuclear translocation to a greater extent and for a longer time in microglia versus oligodendrocytes, and this was followed 24-48 hr later with 3- to 13-fold increases in microglia manganese superoxide dismutase protein levels and 6-fold increases in enzyme activity. Collectively, these data suggest that signals transduced through the p75 receptor activate anti-oxidant mechanisms that protect microglia from TNF-induced injury. Lacking such signals, oligodendrocytes are considerably more vulnerable to the injurious effects of TNF.