Validity of clinically derived cumulative somatosensory impairment index

Assessing Plantar Sensation in the Foot Using the Foot Roughness Discrimination Test (FoRDT): A Reliability and Validity Study in Stroke

BACKGROUND

The plantar foot represents a sensory dynamometric map and is essential for balance and gait control. Sensory impairments are common, yet often difficult to quantify in neurological conditions, particularly stroke. A functionally oriented and quantifiable assessment, the Foot Roughness Discrimination Test (FoRDT), was developed to address these shortcomings.

OBJECTIVE

To evaluate inter- and intrarater reliability, convergent and discriminant validity of the FoRDT.

DESIGN

Test-retest design.

SETTING

Hospital outpatient.

PARTICIPANTS

Thirty-two people with stroke (mean age 70 years) at least 3 months after stroke, and 32 healthy, age-matched controls (mean age 70).

MAIN OUTCOME MEASURES

Roughness discrimination thresholds were quantified utilizing acrylic foot plates, laser cut to produce graded spatial gratings. Stroke participants were tested on three occasions, and by two different raters. Inter- and intrarater reliability and agreement were evaluated with Intraclass Correlation Coefficients and Bland-Altman plots. Convergent validity was evaluated through Spearman rank correlation coefficients (rho) between the FoRDT and the Erasmus modified Nottingham Sensory Assessment (EmNSA).

RESULTS

Intra- and interrater reliability and agreement were excellent (ICC =0.86 [95% CI 0.72-0.92] and 0.90 [95% CI 0.76-0.96]). Discriminant validity was demonstrated through significant differences in FoRDT between stroke and control participants (P < .001). Stroke fallers had statistically significant higher FoRDT scores compared with nonfallers (P = .01). Convergent validity was demonstrated through significant and strong correlations (rho) with the Erasmus MC Nottingham Sensory Assessment (r = .69, P < .01). Receiver operator characteristic curve analysis indicated the novel test to have excellent sensitivity and specificity in predicting the presence of self-reported sensory impairments. Functional Reach test significantly correlated with FoRDT (r = .62, P < .01) whereas measures of postural sway and gait speed did not (r = .16-.26, P > .05).

CONCLUSIONS

This simple and functionally oriented test of plantar sensation is reliable, valid, and clinically feasible for use in an ambulatory, chronic stroke and older population. It offers clinicians and researchers a sensitive and robust sensory measure and may further support the evaluation of rehabilitation targeting foot sensation.

LEVEL OF EVIDENCE

III.

Assessing lower limb position sense in stroke using the gradient discrimination test (GradDT™) and step-height discrimination test (StepDT™): a reliability and validity study

Purpose: To evaluate the psychometric properties of two novel tests of lower limb position sense.Methods: Our newly developed tests assess the discrimination thresholds of under-foot slope and step height perception using a two alternative forced choice approach. Stroke participants (n = 32) and age matched controls (n = 32) were tested. Inter- and intra-rater reliability and agreement, sensitivity and specificity, discriminant and convergent validity were evaluated.Results: Intra-rater reliability for both variants of the gradient discrimination test was excellent; intraclass correlation coefficients (ICC) =0.91 and 0.89. The step height discrimination test had excellent intra-rater reliability and agreement: ICC =0.95. Inter-rater reliability was also excellent in both tests (ICC= 0.85-0.93). Discriminant validity was demonstrated with significant differences in test performance between stroke and control participants (p < 0.001). Our novel tests did not significantly correlate with the proprioceptive component of the Erasmus modified Nottingham Sensory Assessment. Receiver Operating Characteristic curve analysis indicated both novel tests to have greater sensitivity and specificity than the proprioceptive component of the Erasmus modified Nottingham Sensory Assessment in predicting the presence of self-reported sensory impairments. Functional reach test, 10 meter walk test, centre of pressure measurement and reported falls showed significant and moderate to strong correlations with novel test performance (r = 0.40-0.60); the Erasmus modified Nottingham Sensory Assessment did not.Conclusions: Our novel, functionally oriented tests of lower limb position sense are reliable, valid and feasible for use in an ambulatory chronic stroke and elderly population.Implications for rehabilitationThe GradDT™ and StepDT are two novel tests of lower limb position sense which are reliable and valid in a chronic stroke sample.They offer clinicians and researchers sensitive, accurate and clinically usable measures of lower limb position sense.

Age-Related Change in Mobility: Perspectives From Life Course Epidemiology and Geroscience

Mobility is the most studied and most relevant physical ability affecting quality of life with strong prognostic value for disability and survival. Natural selection has built the "engine" of mobility with great robustness, redundancy, and functional reserve. Efficient patterns of mobility can be acquired during development even by children affected by severe impairments. Analogously, age-associated impairments in mobility-related physiological systems are compensated and overt limitations of mobility only occur when the severity can no longer be compensated. Mobility loss in older persons usually results from multiple impairments in the central nervous system, muscles, joints, and energetic and sensory physiological systems. Early preclinical changes in these physiological systems that precede mobility loss have been poorly studied. Peak performance, rate of decline, compensatory behaviors, or subclinical deterioration of physiological resources may cumulatively influence both timing of mobility loss and chances of recovery, but their role as risk factors has not been adequately characterized. Understanding the natural history of these early changes and intervening on them would likely be the most effective strategy to reduce the burden of disability in the population. For example, young women with low bone peak mass could be counseled to start strength resistance exercise to reduce their high risk of developing osteoporosis and fracture later in life. Expanding this approach to other physiological domains requires collecting and interpreting data from life course epidemiological studies, establishing normative measures of mobility, physical function, and physical activity, and connecting them with life course trajectories of the mobility-relevant physiological domains.

Mastoid Vibration Affects Dynamic Postural Control During Gait

Our objective was to investigate how manipulating sensory input through mastoid vibration (MV) could affect dynamic postural control during walking, with and without simultaneous manipulation of the visual and the somatosensory systems. We used three levels of MV (none, unilateral, and bilateral) via vibrating elements placed on the mastoid processes. We combined this with the six conditions of the Locomotor Sensory Organization Test (LSOT) paradigm to challenge the visual and somatosensory systems. We hypothesized that MV would affect both amount and temporal structure measures of sway variability during walking and that, in combination with manipulations of the visual and the somatosensory inputs, MV would augment the effects previously observed. The results confirmed that MV produced a significant increase in the amount of sway variability in both anterior-posterior and medial-lateral directions. Significant changes in the temporal structure of sway variability were only observed in the anterior-posterior direction. Bilateral MV produced larger effects than unilateral stimulation. We concluded that sensory input while walking could be affected using MV. Combining MV with manipulations of visual and somatosensory input could allow us to better understand the contributions of the sensory systems during locomotion.

Assessing Proprioception: A Systematic Review of Possibilities

Proprioception is a vital aspect of motor control and when degraded or lost can have a profound impact on function in diverse clinical populations. This systematic review aimed to identify clinically related tools to measure proprioceptive acuity, to classify the construct(s) underpinning the tools, and to report on the clinimetric properties of the tools. We searched key databases with the pertinent search terms, and from an initial list of 935 articles, we identified 57 of relevance. These articles described 32 different tools or methods to quantify proprioception. There was wide variation in methods, the joints able to be tested, and the populations sampled. The predominant construct was active or passive joint position detection, followed by passive motion detection and motion direction discrimination. The clinimetric properties were mostly poorly evaluated or reported. The Rivermead Assessment of Somatosensory Perception was generally considered to be a valid and reliable tool but with low precision; other tools with higher precision are potentially not clinically feasible. Clinicians and clinical researchers can use the summary tables to make more informed decisions about which tool to use to match their predominant requirements. Further discussion and research is needed to produce measures of proprioception that have improved validity and utility.

Geriatric syndromes and functional status in NSHAP: rationale, measurement, and preliminary findings

INTRODUCTION

The geriatric functional measures and syndromes collected 5 years apart in Waves 1 and 2 of the National Social Life, Health, and Aging Project (NSHAP) data set included: difficulty with activities of daily living and instrumental activities of daily living, the timed up and go, a 3-m timed walk, repeated chair stands, self-reported physical activity, accelerometry-assessed (in)activity, falls, fractures, and frailty. The purpose of this paper was to describe the data collection methods and report preliminary population estimates for each measures.

METHOD

Frequencies, means, or medians were estimated for each measure stratified by age and gender, using the age-eligible samples in Wave 1 (n = 3,005) and Wave 2 (n = 3,196). An adapted phenotypic frailty scale was constructed in the sample common to both waves (n = 2,261). Changes over 5 years were reported for four measures common to both waves.

RESULTS

The functional measures worsened with age (p < .001). The syndromes were more prevalent with age except "all fractures" (p value range < .001-.03). Functional measures were worse among females than males except chair stand performance and the accelerometry-assessed (in)activity measures (p value range < .001-.01). The syndromes were more common among females than males except Wave 2 falls and Wave 2 hip fractures (p value range < .001-.03). Changes from Wave 1 to 2 revealed 11.5%-25.2% of individuals reported better health and 21.3%-44.7% reported worse health.

DISCUSSION

The NSHAP provides a comprehensive assessment of geriatric health. Our findings are consistent with the literature and support the construct of the study measures.

Locomotor sensory organization test: a novel paradigm for the assessment of sensory contributions in gait

Feedback based balance control requires the integration of visual, proprioceptive and vestibular input to detect the body's movement within the environment. When the accuracy of sensory signals is compromised, the system reorganizes the relative contributions through a process of sensory recalibration, for upright postural stability to be maintained. Whereas this process has been studied extensively in standing using the Sensory Organization Test (SOT), less is known about these processes in more dynamic tasks such as locomotion. In the present study, ten healthy young adults performed the six conditions of the traditional SOT to quantify standing postural control when exposed to sensory conflict. The same subjects performed these six conditions using a novel experimental paradigm, the Locomotor SOT (LSOT), to study dynamic postural control during walking under similar types of sensory conflict. To quantify postural control during walking, the net Center of Pressure sway variability was used. This corresponds to the Performance Index of the center of pressure trajectory, which is used to quantify postural control during standing. Our results indicate that dynamic balance control during locomotion in healthy individuals is affected by the systematic manipulation of multisensory inputs. The sway variability patterns observed during locomotion reflect similar balance performance with standing posture, indicating that similar feedback processes may be involved. However, the contribution of visual input is significantly increased during locomotion, compared to standing in similar sensory conflict conditions. The increased visual gain in the LSOT conditions reflects the importance of visual input for the control of locomotion. Since balance perturbations tend to occur in dynamic tasks and in response to environmental constraints not present during the SOT, the LSOT may provide additional information for clinical evaluation on healthy and deficient sensory processing.

Drawing on related knowledge to advance multiple sclerosis falls-prevention research

There is much to be learned from falls-related research outside the field of multiple sclerosis (MS), as well as from work within the MS field but not specific to falls or falls prevention. This article describes three examples of such bodies of work that have potential to broaden approaches to falls-prevention research: 1) sensory components of postural control among older adults, 2) lessons learned from physical activity promotion among people with spinal cord injury (SCI), and 3) aging among people with MS. Age-related deterioration in visual, vestibular, and somatosensory systems or in sensory integration can adversely affect postural control and can contribute to falls in older people. Sensory-specific interventions designed for improving balance in older people could be adapted for preventing falls in individuals with MS. Spinal Cord Injury (SCI) Action Canada's strategy for disseminating physical activity promotion interventions for adults with SCI has been successful and widely accepted by community partners. Many of the peer-based interventions developed by SCI Action Canada are potentially relevant and could be adapted to the MS population for both physical activity promotion and falls prevention. Considering that older people with MS constitute a growing proportion of the MS population and over 70% of older people with MS report moderate to extreme balance problems, falls prevention should be one of the key components, particularly for MS management in older or more disabled groups. Overall, given people's different ages, symptoms, strengths, and barriers, a tailored MS falls-prevention intervention that includes peer/caregiver support is critical.

Somatosensory findings of pusher syndrome in stroke patients

Objective

To investigate the somatosensory findings of pusher syndrome in stroke patients.

Methods

Twelve pusher patients and twelve non-pusher patients were enrolled in this study. Inclusion criteria were unilateral stroke, sufficient cognitive abilities to understand and follow instructions, and no visual problem. Patients were evaluated for pusher syndrome using a standardized scale for contraversive pushing. Somatosensory finding was assessed by the Cumulative Somatosensory Impairment Index (CSII) and somatosensory evoked potentials (SEPs) at 1 and 14 weeks after the stroke onset. Data of SEPs with median and tibial nerve stimulation were classified into the normal, abnormal, and no response group.

Results

In the baseline characteristics (sex, lesion character, and side) of both groups, significant differences were not found. The score of CSII decreased in both groups at 14 weeks (p<0.05), but there were no significant differences in the CSII scores between the two groups at 1 and 14 weeks. There were no significant differences in SEPs between the two groups at 1 and 14 weeks after the stroke onset.

Conclusion

It appears that somatosensory input plays a relatively minor role in pusher syndrome. Further study will be required to reveal the mechanism of pusher syndrome.

Performance on five times sit-to-stand task as a predictor of subsequent falls and disability in older persons

OBJECTIVE

To investigate whether the performance on 5 times sit-to-stand test (5tSTS) can predict subsequent falls, fall-related fracture, and activities of daily living (ADL) and instrumental activities of daily living (IADL) disability in older persons.

METHODS

A total of 948 older adults (age ≥ 60) participated in this study. Ability and the time to finish 5tSTS were recorded at baseline. Number of falls, fall-related fractures, and the ability to complete ADL and IADL without assistance were recorded retrospectively at baseline and at the 3-year follow-up.

RESULTS

Inability to complete 5tSTS was a marginal predictor of falls (OR = 4.22) and a significant predictor of ADL- (OR = 24.70) and IADL-related disability (OR = 17.10) at 3-year follow-up. The need of longer time to complete 5tSTS was predictive of developing IADL-related disability at 3-year follow-up (OR = 4.22 [> 16.6 s]; OR = 2.49 [13.7 - 16.6 s]).

DISCUSSION

5tSTS is an easily administered tool which can be used to predict subsequent ADL- and IADL-related disability.

Role of muscle mass and muscle quality in the association between diabetes and gait speed

OBJECTIVE

Older people with type 2 diabetes are at high risk of mobility disability. We investigated the association of diabetes with lower-limb muscle mass and muscle quality to verify whether diabetes-related muscle impairments mediate the association between diabetes and low walking speed.

RESEARCH DESIGN AND METHODS

We performed a cross-sectional analysis of 835 participants (65 years old and older) enrolled in the InCHIANTI (Invecchiare in Chianti, aging in the Chianti area) population-based study. Total, muscular, and fat cross-sectional areas of the calf and relative muscle density were measured using peripheral quantitative computerized tomography. Indicators of muscle performance included knee-extension torque, ankle plantar flexion and dorsiflexion strength, lower-extremity muscle power, and ankle muscle quality (ratio of ankle strength to the muscle area [kilograms per centimeters squared]). Gait performance was assessed by 4- and 400-m walking speed. Diabetes was ascertained by standard American Diabetes Association criteria.

RESULTS

Prevalence of diabetes was 11.4%. After adjustment for age and sex, participants with diabetes had lower muscle density, knee and ankle strength, and muscle power and worse muscle quality (all P < 0.05). Diabetic participants were also slower on both 4-m (β: -0.115 ± 0.024 m/s, P < 0.001) and 400-m (β:-0.053 ± 0.023 m/s, P < 0.05) walking tests. In multivariable linear regression models, lower-limb muscle characteristics accounted for 24.3 and 15.1% of walking speed difference comparing diabetic and nondiabetic subjects in the 4- and 400-m walks, respectively.

CONCLUSIONS

In older persons, diabetes is associated with reduced muscle strength and worse muscle quality. These impairments are important contributors of walking limitations related to diabetes.

Sensorimotor and psychosocial correlates of adaptive locomotor performance in older adults

OBJECTIVE

To identify sensorimotor and psychosocial factors independently associated with an inability to perform adaptive walking tasks in older adults.

DESIGN

Cross-sectional cohort study.

SETTING

Population-based older cohort.

PARTICIPANTS

Community-living elderly (N=720; age ≥65y) who could walk 7m at self-selected normal speed.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Walking performance was assessed in 4 walking tests: fast walking, obstacle crossing, narrow-based walking, and walking while talking. Possible correlates of the inability to perform the walking test included knee extensor strength, lower limb coordination, Cumulative Somatosensory Impairment Index (CSII), visual acuity and contrast sensitivity, cognition, depression, personal mastery, social support, and years of education.

RESULTS

The results of binary logistic regression analyses, adjusted for demographics and self-selected normal speed, demonstrated that poor knee extensor strength was associated with an inability to perform tasks demanding an increase in walking speed (fast walking and obstacle crossing). Both poor lower limb coordination and higher CSII were significantly associated with failure in tests that demanded precise control over foot placement (obstacle crossing and narrow-based walking). Higher CSII was associated with failure in all tests except in the walking while talking. In contrast, poor cognition was associated with an inability to perform walking while talking. Poor personal mastery was the only variable that was associated with failure in all walking tests.

CONCLUSIONS

The results demonstrated a systematic and coherent pattern in these associations and indicated possible sensorimotor and psychological parameters that should be specifically investigated and should be intervened if a patient reports a difficulty/inability in walking in certain situations.