The Relation Between Walking Capacity and Clinical Correlates in Survivors of Chronic Spinal Poliomyelitis

Should We Trust Perceived Effort for Loading Control and Resistance Exercise Prescription After ACL Reconstruction?

CONTEXT

The rating of perceived effort (RPE) is a common method used in clinical practice for monitoring, loading control, and resistance training prescription during rehabilitation after rupture and anterior cruciate ligament reconstruction (ACLR). It is suggested that the RPE results from the integration of the afferent feedback and corollary discharge in the motor and somatosensory cortex, and from the activation of brain areas related to emotions, affect, memory, and pain (eg, posterior cingulate cortex, precuneus, and prefrontal cortex). Recent studies have shown that rupture and ACLR induce neural adaptations in the brain commonly associated with the RPE. Therefore, we hypothesize that RPE could be affected because of neural adaptations induced by rupture and ACLR.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

RPE could be directly altered by changes in the activation of motor cortex, posterior cingulate cortex, and prefrontal cortex. These neural adaptations may be induced by indirect mechanisms, such as the afferent feedback deficit, pain, and fear of movement (kinesiophobia) that patients may feel after rupture and ACLR.

CONCLUSION

Using only RPE for monitoring, loading control, and resistance training prescription in patients who had undergone ACLR could lead to under- or overdosing resistance exercise, and therefore, impair the rehabilitation process.

STRENGTH-OF-RECOMMENDATION TAXONOMY

3C.

The 6-min walk test as a new outcome measure in Amyotrophic lateral sclerosis

One of the issues highlighted in amyotrophic lateral sclerosis (ALS) clinical trials is the lack of appropriate outcome measures. The aim of this multicentric study was to evaluate the 6-min walk test (6MWT) as tool to monitor the natural history of a cohort of ALS patients followed up over a 6-month interval. Forty-four ambulant patients were assessed at baseline and after 1, 3 and 6 months. Eight out of forty-four lost the ability to walk before the end of the study. The 6MWT and the objective measures linked to motor function, such as 10 m walking test (10MWT) and Time-up and go (TUG), the ALSFRS-R and the ALSFRS-R items 7–9 showed a good responsiveness to change over the 6-month interval. There was a strong correlation between 6 and 10MWT, TUG, ALSFRS-R, ALSFRS-R items 7–9 and FVC% at baseline. There was no correlation with Edinburgh Cognitive and Behavioural ALS Screen (ECAS) and Modified Borg Scale (MBS). The Δ of 6MWT from T0 to T6 significantly correlated with the Δs of 10MWT and TUG. There was no correlation with the Δs of ALSFRS-R, ALSFRS-R items 7 9, ECAS, MBS and FVC%. The discordance between changes of the 6MWT and ALSFRS-R at 6 month highlights the different content validity among these instruments. The concordance among 6MWT, 10MWT and TUG indicates that the 6MWT is an objective, sensitive and robust tool to measure motor performances in a longitudinal setting. The main limitations of our study were the small sample size and the high percentage of patients (18%) lost at follow-up. Therefore, further studies on larger cohorts, and exploring the relation between 6MWT and need of ventilator support or survival could strengthen our results.

Lower-limb muscle strength, static and dynamic postural stabilities, risk of falling and fear of falling in polio survivors and healthy subjects

INTRODUCTION

This study investigated the association between preserved lower-limb muscle strength, dynamic and static postural stability, risk of falling, and fear of falling in polio survivors. We also investigated whether these clinical features differ between polio survivors and healthy controls. Methods: This quasi-experimental study enrolled 16 polio survivors (13 underwent a complete-case analysis) and 12 age- and sex-matched healthy controls. Participants were assessed by the manual muscle test, Berg Balance Scale, force platform posturography, and Falls Efficacy Scale. Between-group mean differences with confidence intervals (MD, CI 95%) and Spearman's ρ are reported. Results: Compared to healthy controls, polio survivors presented reduced muscle strength (MD = -13, CI 95% -16 to -9 points), lower dynamic postural stability (MD = -14, CI 95% -19 to -8 points), and increased fear of falling (MD = 14, CI 95% 10-18 points) (all P < 0.001). In polio survivors, lower-limb muscle strength was correlated with dynamic (ρ = 0.760) and static postural stability (ρ = 0.738-0.351), risk of falling (ρ = -0.746), and fear of falling (ρ = -0.432). Dynamic postural stability was correlated with risk of falling (ρ = -0.841), fear of falling (ρ = -0.277), and static postural stability (ρ = -0.869 to -0.435; ρ = -0.361 to -0.200, respectively). Risk and fear of falling were also correlated (ρ = 0.464). Discussion: Polio survivors exhibited impaired dynamic postural stability but preserved static stability and increased risk of falling and fear of falling. Preserved lower-limb muscle strength, postural stability, fear of falling, and risk of falling are associated clinical features in this population.

Predictors of changes in gait performance over four years in persons with late effects of polio

BACKGROUND

Reduced gait performance is common in persons with late effects of polio.

OBJECTIVE

To identify predictors of change in gait performance over four years in persons with late effects of polio.

METHODS

Gait performance was assessed annually in 51 ambulatory persons (mean age 64 years, SD 6) by the Timed "Up & Go" (TUG), Comfortable and Fast Gait Speed (CGS, FGS), and 6-Minute Walk Test (6MWT). Isokinetic knee extensor and flexor muscle strength was measured with a Biodex dynamometer. Mixed Linear Models were used to analyze changes in gait performance and to identify any predictors of change among the covariates gender, age, body mass index, time with new symptoms, baseline reduction in gait performance and knee muscle strength.

RESULTS

There were significant linear effects over time (reduction per year) for three gait performance tests; CGS (0.8%; p < 0.05), FGS (1.7%; p < 0.001), and 6MWT (0.7%; p < 0.05) with significant random effects for all tests. The strongest predictor of a change in gait performance was the individual variations in the knee flexor strength (p < 0.001).

CONCLUSION

The small gradual reduction in gait performance over time in persons with late effects of polio is primarily determined by the individual variations in the knee flexor strength.

Poliomyelitis

Poliomyelitis, often termed "polio," is an acute infectious disease caused by an enterovirus which damages the anterior horn cells of the spinal cord and brainstem. Progress to lower motor neurone cell death leads to disruption of motor units and subsequent muscle weakness or complete paralysis. Although the virus is mostly eradicated from the Western world, postpolio decline is prevalent among people aged 60 years and over. It is characterized primarily by fatigability and muscle weakness, but pain is also common. Reductions in lower-limb muscle strength, voluntary drive, and endurance are likely to contribute to the impaired balance control, slow gait, and dysfunctional lower-limb kinematics reported in polio survivors. Given these significant risk factors, polio survivors fall up to four times more often than their age-matched healthy peers. Interventions to improve function, reduce disability, and prevent falls in polio survivors are therefore clinically relevant but studies are lacking, limiting the evidence base. Balance training, cognitive behavioral therapy, and orthoses prescription might be recommended. Muscle-strengthening programs should be carefully designed and delivered due to their potential detrimental effects related to excessive use and potential dysfunction of motor neurones and their axons.

The effects of a home-based arm ergometry exercise programme on physical fitness, fatigue and activity in Polio survivors: a randomised controlled trial

Objective:

To investigate the effect of an eight-week home-based arm ergometry aerobic exercise programme on physical fitness, fatigue, activity and quality of life in Polio Survivors.

Design:

An assessor blinded randomised controlled trial.

Setting:

Home-based exercise.

Subjects:

Fifty-five Polio survivors randomised to exercise or control groups.

Intervention:

Home-based arm ergometry at an intensity of 50%-70% maximum heart rate, compared with usual physiotherapy care.

Main measures:

The Six-minute Arm Test, Fatigue Severity Scale, Physical Activity Scale for Individuals with Physical Disabilities and SF-36. Assessments were completed at baseline and at eight weeks.

Results:

There was no significant difference in the primary outcome, exercising heart rate during the Six-minute Arm Test, between the groups at follow-up [97.6 (SD10.1) compared to 102.4 (SD13.7) beats per minute ( P=0.20)]. Blood pressure was significantly lower in the intervention group at follow-up [systolic blood pressure 132(18.6)mmHg compared to 144.1(14.6)mmHg ( P=0.002)]. There were no between group differences in the Fatigue Severity Scale ( P=0.25) or Physical Activity Scale for Individuals with Physical Disabilities ( P=0.49), with a small difference in SF-36 physical component score ( P=0.04).

Conclusions:

This home-based arm ergometry programme successfully facilitated aerobic exercise in Polio Survivors, but did not result in a significant change in physical fitness, measured by the Six-minute Arm Test.

Novel outcome measures for Charcot-Marie-Tooth disease: validation and reliability of the 6-min walk test and StepWatch(™) Activity Monitor and identification of the walking features related to higher quality of life

BACKGROUND AND PURPOSE

Charcot-Marie-Tooth (CMT) disease is the most common inherited neuropathy, but therapeutic options have been limited to symptom management. Past pharmacological trials have failed, possibly due to insensitive outcome measures (OMs). The aim of the current study was to evaluate the validity and reliability of the 6-min walk test (6MWT) and StepWatch(™) Activity Monitoring (SAM) with other previously validated OMs in CMT disease.

METHODS

A prospective multicenter study was performed, consecutively enrolling 168 CMT patients (104 with CMT1A, 27 with CMT1B, 37 with X-linked CMT) from Italian centers specializing in CMT care.

RESULTS

Statistical analysis showed that the 6MWT was highly related with all previously used OMs. Some, but not all, SAM parameters were related to commonly used OMs but may provide more information about quality of life.

CONCLUSIONS

The current study demonstrated the validity and reliability of the 6MWT and SAM as OMs for CMT. Moreover, SAM provides data that correlate better with quality of life measures, making it useful in future rehabilitation trials.

Assessment of subjective and motor fatigue in Polio survivors, attending a Postpolio clinic, comparison with healthy controls and an exploration of clinical correlates

PURPOSE

Polio survivors experience declining mobility, pain and fatigue. The extent of motor fatigue and its impact on mobility and quality of life, in addition to other commonly reported impairments requires evaluation.

METHODS

An observational, case-control, cross-sectional design was used to assess 30 Polio survivors and 30 age- and sex-matched controls. Muscle strength and motor fatigue were assessed using fixed dynamometry. Fatigue, pain and quality of life were assessed using the Piper Fatigue Scale, the Fatigue Severity Scale, visual analogue scales and the RAND Short Form-36, respectively. An 8-min walking test, including physiological cost index (PCI), evaluated mobility.

RESULTS

A significant difference in motor fatigue was identified only in hand grip (p = 0.03). Polio survivors were significantly weaker (p < 0.001) and more fatigued (p < 0.001) than controls. Motor fatigue was not related to subjective fatigue, mobility or quality of life. Muscle strength predicted mobility. Pain and fatigue were associated with lower mental quality of life, while PCI was associated with physical quality of life.

CONCLUSION

Motor fatigue has been identified in Polio survivors but was only significantly different in hand grip, using this approach. Pain, fatigue and elevated energy cost of walking negatively influenced quality of life. Motor fatigue was unrelated to subjective fatigue, mobility or quality of life.

The repeatability of gait speed and physiological cost index measurements in working adults

OBJECTIVES

To determine the performance characteristics of gait speed measurements and the physiological cost index (PCI; heart rate change/gait speed) in working adults.

METHODS

Gait speeds, heart rate changes, and non-steady state PCIs were calculated in 61 volunteers who worked in our health sciences center. These subjects completed 9 separate 100-foot walk tests in 3 separate sessions.

RESULTS

The mean heart rate change after a 100-foot walk was 16.6 ± 8.1 beats per minute. The mean gait speed was 76.1 ± 9.6 meters per minute, and the mean PCI was 0.22 ± 0.11 beats per meter. There were highly significant correlations among all measurements on the 9 separate tests (correlation coefficients 0.41-0.95); gait speed measurements had the highest correlations (0.91-0.95). In a multivariable model hypertension and arthritis were associated with reduced gait speeds.

CONCLUSION

Gait speed, heart rate changes, and non-steady state PCIs have good repeatability when measured over short walks. This information provides a rapid physiological assessment and a method for measuring changes in functional status in healthy subjects and most patients.

Walking capacity evaluated by the 6-minute walk test in spinal and bulbar muscular atrophy

Spinal and bulbar muscular atrophy (SBMA) is an adult-onset motor neuron disease caused by a CAG repeat expansion in the androgen receptor gene. Because the progression of SBMA is slow, it is plausible to identify biomarkers that monitor disease course for therapeutic development. To verify whether the 6-min walk test (6MWT) is a biomarker of SBMA, we performed the 6MWT in 35 genetically confirmed patients and in 29 age-matched healthy controls. The walk distance covered within 6 min (6MWD) was significantly less in SBMA than it was in controls (323.3 +/- 143.9 m and 637.6 +/- 94.2 m, respectively; P < 0.001). In test-retest analysis, the intraclass correlation coefficient for the 6MWD was high in SBMA patients (r = 0.982). In a 1-year follow-up the 6MWD significantly decreased at a rate of 11.3% per year. Our observations suggest that the 6MWT is a biomarker that can be used to monitor progression of motor impairment in SBMA.

Test-retest reliability and minimal detectable change on balance and ambulation tests, the 36-item short-form health survey, and the unified Parkinson disease rating scale in people with parkinsonism

BACKGROUND AND PURPOSE

Distinguishing between a clinically significant change and change due to measurement error can be difficult. The purpose of this study was to determine test-retest reliability and minimal detectable change for the Berg Balance Scale (BBS), forward and backward functional reach, the Romberg Test and the Sharpened Romberg Test (SRT) with eyes open and closed, the Activities-specific Balance Confidence (ABC) Scale, the Six-Minute Walk Test (6MWT), comfortable and fast gait speed, the Timed "Up & Go" Test (TUG), the Medical

OUTCOMES

Study 36-Item Short-Form Health Survey (SF-36), and the Unified Parkinson Disease Rating Scale (UPDRS) in people with parkinsonism.

SUBJECTS

Thirty-seven community-dwelling adults with parkinsonism (mean age=71 years) participated. The Hoehn and Yahr Scale median score of 2 was on the lower end of the scale; however, the scores ranged from 1 to 4.

METHODS

Subjects were tested twice by the same raters, with 1 week between tests. Test-retest reliability was calculated using intraclass correlation coefficients (ICCs). Minimal detectable change was calculated using a 95% confidence interval (MDC(95)).

RESULTS

The ICCs for test-retest reliability were above .90 for the BBS, ABC Scale, SRT with eyes closed, 6MWT, and comfortable and fast gait speeds. The MDC(95) values for those functional tests were: BBS=5/56, ABC Scale=13%, SRT with eyes closed=19 seconds, 6MWT=82 m, comfortable gait speed=0.18 m/s, and fast gait speed=0.25 m/s. The ICCs for test-retest reliability of SF-36 scores were above .80, with the exception of the social functioning subscale. The MDC(95) values for the SF-36 ranged between 19% and 45%. The MDC(95) values for the UPDRS Activities of Daily Living section, Motor Examination section, and total scores were 4/52, 11/108, and 13/176, respectively.

DISCUSSION AND CONCLUSION

Minimal detectable change values are useful to therapists in rehabilitation and wellness programs in determining whether change during or after intervention is clinically significant. High test-retest reliability of scores for the BBS, ABC Scale, SRT with eyes closed, 6MWT, and gait speed make them trustworthy functional assessments in people with parkinsonism. The SF-36 and UPDRS provide quality-of-life and disease severity rating values in the ongoing assessment of people with parkinsonism.