Validity of heart rate indexes to assess wheeling efficiency in patients with spinal cord injuries

Robotic Locomotor Training Leads to Cardiovascular Changes in Individuals With Incomplete Spinal Cord Injury Over a 24-Week Rehabilitation Period: A Randomized Controlled Pilot Study

OBJECTIVE

To describe the effect of robotic locomotor training (RLT) and activity-based training (ABT) on cardiovascular indices during various physiological positions in individuals with spinal cord injury.

DESIGN

Randomized controlled pilot study.

SETTING

Private practice: Therapy & Beyond Centre - Walking with Brandon Foundation, Sports Science Institute of South Africa, Cape Town, South Africa.

PARTICIPANTS

Participants with chronic traumatic motor incomplete tetraplegia (N=16) who resided in the Western Cape, South Africa.

INTERVENTION

Robotic locomotor training (Ekso GT) and activity-based training over a 24-week intervention.

MAIN OUTCOME MEASURES

Brachial and ankle blood pressure, heart rate, heart rate variability, and cardiovascular efficiency during 4 physiological positions.

RESULTS

No differences between groups or over time were evident in resting systolic and diastolic blood pressure, ankle systolic pressure, ankle brachial pressure index, and heart rate variability. Standing heart rate at 24 weeks was significantly higher in the ABT group (95.58±12.61 beats/min) compared with the RLT group (75.14±14.96 beats/min) (P=.05). In the RLT group, no significant changes in heart rate variability (standard deviation R-R interval and root mean square of successive differences) was found between the standing and 6-minute walk test physiological positions throughout the intervention. Cardiovascular efficiency in the RLT group during the 6-minute walk test improved from 11.1±2.6 at baseline to 7.5±2.8 beats per meter walked at 6 weeks and was maintained from 6 to 24 weeks.

CONCLUSIONS

Large effect sizes and significant differences between groups found in this pilot study support the clinical effectiveness of RLT and ABT for changing cardiovascular indices as early as 6 weeks and up to 24 weeks of rehabilitation. RLT may be more effective than ABT in improving cardiac responses to orthostatic stress. Based on heart rate variability metrics, the stimulus of standing has comparable effects to RLT on the parasympathetic nervous system. Cardiovascular efficiency of exoskeleton walking improved, particularly over the first 6 weeks. Both the RLT and ABT interventions were limited in their effect on brachial and ankle blood pressure. A randomized controlled trial with a larger sample size is warranted to further examine these findings.

A Preliminary Evaluation of Energy Efficiency for Children with Cerebral Palsy for Driving A Manual Wheelchair and Walking: Use of the Total Heart Beat Index

Aims: This study aims to compare the total heart beat index (THBI) in evaluating energy efficiency between using a manual wheelchair and walking for children with cerebral palsy (CP). Methods: The energy efficiency was measured in 21 participants with CP (mean age, 13.6 ± 3.4 years) who walk or drive a manual wheelchair using a square course. THBI was calculated as total number of heart beats during the exercise period/total distance traveled. Results: Significant differences in the THBI were observed between Gross Motor Function Classification System (GMFCS) levels III and IV (p = .049, effect size = 1.60). No significant differences in THBI were observed between GMFCS levels II and III or between GMFCS levels II and IV (p > .05). Conclusions: The energy efficiency of children with CP who use a manual wheelchair in this study was equal to or better than that for walking.

Are Body Composition, Strength, and Functional Independence Similarities Between Spinal Cord Injury Classifications? A Discriminant Analysis

CONTEXT

There seems to be no consensus on which aspects better distinguish the different levels of spinal cord injury regarding body composition, strength, and functional independence.

OBJECTIVE

The study aimed to determine which variables better differentiate tetraplegia (TP) from paraplegia and high paraplegia (HP) from low paraplegia (LP).

DESIGN

Cross-sectional study.

SETTING

Rehabilitation hospital network.

PATIENTS

Forty-five men with spinal cord injury, n = 15 for each level (TP, HP, and LP) causing complete motor impairment (American Spinal Injury Association Impairment Scale: A or B) were enrolled in the study.

MAIN OUTCOME MEASURES

The 1-maximum repetition test, functional independence measure, spinal cord independence measure, and body composition (skinfold sum, body fat percentage, and body mass index) were assessed. Discriminant analysis was carried out using the Wilks lambda method to identify which strength and functional variables can significantly discriminate subjects for injury classification (TP, HP, and LP).

RESULTS

The discriminant variable for TP versus HP was body mass index and for TP versus LP was 1-maximum repetition (P ≤ .05). There were no variables that discriminated HP versus LP.

CONCLUSIONS

The discriminant variables for TP versus HP and TP versus LP were body mass index and 1-maximum repetition, respectively. The results showed that HP and LP are similar for strength and functional variables.

Differences of Relative and Absolute Strength of Individuals With Spinal Cord Injury From Able-Bodied Subjects: A Discriminant Analysis

CONTEXT

Strength training is one of the most common interventions employed to increase functional independence during rehabilitation of individuals with spinal cord injury (SCI). However, in the literature, different results have been reported in terms of strength modifications after a SCI compared with a control group (CG).

OBJECTIVE

This study aimed to verify whether discriminant analysis using relative and absolute strength is able to discriminate individuals with different levels of SCI from a CG and to compare strength values of men with different levels of SCI with a CG.

DESIGN

Cross-sectional study.

SETTING

Rehabilitation hospital setting.

PARTICIPANTS

A total of 36 individuals with SCI stratified in tetraplegia (TP; C6-C8), high paraplegia (HP; T1-T6), and low paraplegia (LP; T7-L2), and 12 matched control subjects were enrolled in the study.

MAIN OUTCOME MEASURES

The subjects performed a maximum strength test of elbow extension/flexion and also shoulder abduction/adduction and flexion/extension in an isokinetic dynamometer. Discriminant analysis was carried out to identify which strength variables would be able to discriminate the TP, HP, or LP groups from the CG. A 1-way analysis of variance was performed to compare peak torque and agonist/antagonist ratio means.

RESULTS

Shoulder adduction, followed by elbow extension peak torque, was the best variable for discriminating the TP group from the CG (function coefficients: -0.056 and 0.051, respectively, Wilks Λ = 0.41, P ≤ .05). There were no significant differences between the HP group, LP group, and CG.

CONCLUSIONS

The strength similarity of the paraplegic groups and the CG should not be extrapolated for activities of daily living or sports. The TP group demonstrated lower peak torque for all movements than the CG.

The addition of three new items in the Adapted Manual Wheelchair Circuit improves the discrimination between different levels of spinal cord injury

Purpose: To determine whether the inclusion of three additional items improved the discriminative capacity of the Adapted Manual Wheelchair Circuit (AMWC). Design: Cross-sectional study. Methods: A total of 126 men (median age 28.9 years [percentiles 25 and 75: 23.7; 38.5 years]) with spinal cord injury were consecutively enrolled and divided into three subgroups: high paraplegia (HP), medium paraplegia (MP), and low paraplegia (LP). The participants performed the AMWC with three additional items. Ability score and total time of AMWC (AMWC_AS and AMWC_TT) and AMWC plus the three additional items (AMWC+3_AS and AMWC+3_TT), 3 min of overground wheeling test and performance score were evaluated. Results: AMWC was not able to discriminate HP from MP and LP (Wilks' lambda = 0.93; P= 0.07). In contrast, AMWC+3 was able to discriminate between the three subgroups (Wilks' lambda = 0.86; P≤ 0.05). AMWC+3_AS presented a better sensitivity compared to AMWC_AS (lower success rate for all subgroups, 38.5% vs. 82.1% for HP; 49.0% vs. 75.5% for MP; 78.9% vs. 94.7% for LP). The LP group presented a significant higher AMWC+3_AS compared to MP and HP (17.0 vs. 16.5 and 16.5, respectively, P≤ 0.05). AMWC+3_TT was significantly lower in LP compared to MP and HP (139.85 s vs. 242.52 s and 326.21 s, respectively, P≤ 0.05). Conclusion: The AMWC+3 outcomes were able to discriminate between HP, MP, and LP subgroups, and the addition of the three items enhanced the sensitivity of the wheelchair circuit. The performance of LP was more evident with significant differences compared to HP and MP for all AMWC+3 outcomes.

Cross-cultural validation of a Brazilian version of the adapted manual wheelchair circuit (AMWC-Brazil)

Purpose: To translate, culturally adapt and validate the Adapted Manual Wheelchair Circuit (AMWC) into Brazilian-Portuguese. Design: Cross-sectional study. Methods: Sixty-six men (median age of 30.5 years [percentiles 25 and 75: 24.0; 38.3 years]) with traumatic spinal cord injury were consecutively enrolled and divided into two groups: tetraplegia (TP) and paraplegia (PP). The participants performed the AMWC-Brazil and were evaluated by the Spinal Cord Injury Measure version III (SCIM-III). Translation, translation synthesis, back-translation, committee review and construct validity were adopted for the cross-cultural adaptation. Construct validity was performed by testing whether the test scores were significantly correlated (Spearman's correlation coefficient) to the subjects' injury level, age, time since injury, body mass index (BMI) and SCIM-III scale. Results: All the AMWC-Brazil's outcomes were significantly correlated with SCIM-III total score and subscales (P ≤ 0.01). However, when the analyses were stratified over injury level, only the TP showed a high correlation between the AMWC-Brazil's outcomes and the SCIM-III. For construct validity, 4 of 5 hypotheses were confirmed. Only BMI was not a significant predictor of the AMWC-Brazil outcomes. Conclusion: The AMWC was successfully translated to the Brazilian-Portuguese (AMWC-Brazil) and presented high and satisfactory construct validity.

Validity of activity monitors in wheelchair users: A systematic review

Assessing physical activity (PA) in manual wheelchair users (MWUs) is challenging because of their different movement patterns in comparison to the ambulatory population. The aim of this review was to investigate the validity of portable monitors in quantifying PA in MWUs. A systematic literature search was performed. The data source was full reports of validation and evaluation studies in peer-reviewed journals and conference proceedings. Eligible articles between January 1, 1999, and September 18, 2015, were identified in three databases: PubMed, Institute of Electrical and Electronics Engineers, and Scopus. A total of 164 articles (158 from the databases and 6 from the citation/reference tracking) were identified, and 29 met the eligibility criteria. Two investigators independently extracted the characteristics from each selected article following a predetermined protocol and completed seven summary tables describing the study characteristics and key outcomes. In the identified studies, the monitors were used to assess three types of PA measures: energy cost, user movement, and wheelchair movement. The customized algorithms/monitors did not estimate energy cost in MWUs as well as the commercial monitors did in the ambulatory population; however, they showed fair accuracy in measuring both wheelchair and user movements.

Measurement of Physical Activity and Energy Expenditure in Wheelchair Users: Methods, Considerations and Future Directions

Accurately measuring physical activity and energy expenditure in persons with chronic physical disabilities who use wheelchairs is a considerable and ongoing challenge. Quantifying various free-living lifestyle behaviours in this group is at present restricted by our understanding of appropriate measurement tools and analytical techniques. This review provides a detailed evaluation of the currently available measurement tools used to predict physical activity and energy expenditure in persons who use wheelchairs. It also outlines numerous considerations specific to this population and suggests suitable future directions for the field. Of the existing three self-report methods utilised in this population, the 3-day Physical Activity Recall Assessment for People with Spinal Cord Injury (PARA-SCI) telephone interview demonstrates the best reliability and validity. However, the complexity of interview administration and potential for recall bias are notable limitations. Objective measurement tools, which overcome such considerations, have been validated using controlled laboratory protocols. These have consistently demonstrated the arm or wrist as the most suitable anatomical location to wear accelerometers. Yet, more complex data analysis methodologies may be necessary to further improve energy expenditure prediction for more intricate movements or behaviours. Multi-sensor devices that incorporate physiological signals and acceleration have recently been adapted for persons who use wheelchairs. Population specific algorithms offer considerable improvements in energy expenditure prediction accuracy. This review highlights the progress in the field and aims to encourage the wider scientific community to develop innovative solutions to accurately quantify physical activity in this population.

Discriminatory validity of the Aspects of Wheelchair Mobility Test as demonstrated by a comparison of four wheelchair types designed for use in low-resource areas

Background

Comparative effectiveness research on wheelchairs available in low-resource areas is needed to enable effective use of limited funds. Mobility on commonly encountered rolling environments is a key aspect of function. High variation in capacity among wheelchair users can mask changes in mobility because of wheelchair design. A repeated measures protocol in which the participants use one type of wheelchair and then another minimises the impact of individual variation.

Objectives

The Aspects of Wheelchair Mobility Test (AWMT) was designed to be used in repeated measures studies in low-resource areas. It measures the impact of different wheelchair types on physical performance in commonly encountered rolling environments and provides an opportunity for qualitative and quantitative participant response. This study sought to confirm the ability of the AWMT to discern differences in mobility because of wheelchair design.

Method

Participants were wheelchair users at a boarding school for students with disabilities in a low-resource area. Each participant completed timed tests on measured tracks on rough and smooth surfaces, in tight spaces and over curbs. Four types of wheelchairs designed for use in low-resource areas were included.

Results

The protocol demonstrated the ability to discriminate changes in mobility of individuals because of wheelchair type.

Conclusion

Comparative effectiveness studies with this protocol can enable beneficial change. This is illustrated by design alterations by wheelchair manufacturers in response to results.

Influence of Relative Strength on Functional Independence of Patients With Spinal Cord Injury

OBJECTIVE

To investigate the influence of strength values and fat mass on functional independence of men with different spinal cord injury (SCI) levels.

DESIGN

Cross-sectional study.

SETTING

Hospital network.

PARTICIPANTS

Men with SCI (N=45).

INTERVENTIONS

Subjects were assessed in functional independence scales, a 1 repetition maximum (1RM) test, and body composition to detect absolute and relative strength: 1RM divided by body mass (BM) and lean body mass (LBM), respectively.

MAIN OUTCOME MEASURES

Stepwise multiple regression analysis was used to verify the influence of predictors on functional independence (FIM and Spinal Cord Independence Measure [SCIM] scale and subscales). Receiver operating characteristic curves were created to identify cutoff points of strength for functional independence.

RESULTS

The best models for FIM total, FIM mobility, and SCIM total used 1RM as the best predictor (adjusted R²=.75, .67, and .65, respectively; P<.05). Relative strength (1RM/LBM) was the best predictor for SCIM mobility (adjusted R²=.62, P<.05). A FIM score of 69 has a 1RM cutoff point of 50.1kg, and a FIM score of 76 has cutoff points of .73 for 1RM/BM and .91 for 1RM/LBM. A SCIM score of 68 has cutoff points for 1RM, 1RM/BM, and 1RM/LBM of 50.1kg, .77, and .92, respectively.

CONCLUSIONS

Cutoff points of relative strength should be used as determinant variables for independence, health, or sports performance. This study may contribute to more adequate guidance of physical activity during a rehabilitation program and after discharge.