Reliability of five-minute vs. one-hour heart rate variability metrics in individuals with spinal cord injury.

Background: A previous study showed low reliability of 1-h HRV outcomes in participants with spinal cord injury (SCI), but it was not certain whether the low reliability was due to the unrestricted activity of participants. We aimed to investigate test-retest reliability of HRV metrics in individuals with SCI using a 1-h measurement in a supine position. Methods: Individuals with SCI underwent two sessions of 1-h recording of the time between consecutive R waves (RR-intervals) in a supine position. HRV outcomes were obtained from a single 5-min data segment and for the full 1-h recording. HRV parameters of interest were: standard deviation of all normal-to-normal R-R intervals (SDNN) and square root of the mean of the squared differences between successive R-R intervals (RMSSD) (time domain); and high frequency power (HF), low frequency power (LF), very low frequency power (VLF), ultra-low frequency power (ULF) and total power (TP) (frequency domain). Relative reliability was assessed by intraclass correlation coefficient (ICC). Absolute reliability was assessed by coefficient of variation (CV) and Bland-Altman limits of agreement (LoA). Results: Data from 37 individuals (14 with tetraplegia and 23 with paraplegia) were included. Relative reliability was higher for the 1-h (ICCs ranged from 0.13-0.71) than for the 5-min duration (ICCs ranged from 0.06-0.50) in the overall SCI group for all HRV metrics. Participants with tetraplegia had lower relative reliability compared to participants with paraplegia in all HRV metrics for the 5-min duration (ICCs ranged from -0.01-0.34 vs. 0.21-0.57). For the 1-h duration, participants with paraplegia showed higher relative reliability than participants with tetraplegia in all HRV metrics (ICCs ranged from 0.18-0.79 vs. 0.07-0.54) except TP (ICC 0.69 vs. 0.82). In terms of absolute reliability, the CVs and LoAs for the 1-h duration were better than for the 5-min duration. In general, time domain metrics showed better reliability than frequency domain metrics for both durations in participants with tetraplegia and paraplegia. The lowest CV and narrowest 95% LoA were found for SDNN in 5-min and 1-h durations overall and in both lesion levels. Conclusions: The supine position did not provide better reliability compared to unrestricted activity in participants with SCI. HRV analysis using a 5-min duration is of limited value in SCI due to poor reliability. For the 1-h analysis duration, interpretation of the reliability of HRV varies according to lesion level: it is recommended to take lesion level into account when interpreting reliability measures.

Test-retest reliability of short- and long-term heart rate variability in individuals with spinal cord injury.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To investigate test-retest reliability of heart rate variability (HRV) metrics in SCI without restriction of activity over long (24-h) and shorter durations (5-min, 10-min, 1-h, 3-h and 6-h). SETTINGS: University hospital in Khon Kaen, Thailand. METHODS: Forty-five participants (11 with tetraplegia and 34 with paraplegia) underwent two 24-h recordings of RR-intervals to derive time and frequency HRV metrics. Relative reliability was assessed by intraclass correlation coefficient (ICC) and absolute reliability by coefficient of variation (CV) and Bland-Altman limits of agreement (LoA). RESULTS: For 5- and 10-min durations, eight of eleven HRV metrics had moderate to excellent reliability (ICC 0.40-0.76); the remaining three were poor (ICC < 0.4). HRV values from 1-h and 3-h durations showed moderate to excellent reliability (ICC of 0.46-0.81), except for 1-h reliability of ULF and TP (ICC of 0.06 and 0.30, respectively). Relative reliability was excellent (ICC of 0.77-0.92) for 6-h and 24-h durations in all HRV metrics. Absolute reliability improved as recording duration increased (lower CVs and narrower LoAs). Participants with high AD risk (SCI level at or above T6) showed lower test-retest reliability of HF and LF values than participants with low AD risk. CONCLUSION: Relative reliability of HRV was excellent for 6-h and 24-h. The best absolute reliability values were for 24-h duration. Time-domain outcomes were more reliable than frequency domain outcomes. Participants with high risk of AD, particularly those with tetraplegia, showed lower reliability, especially for HF and LF.

Effects of repetitive peripheral magnetic stimulation vs. conventional therapy in the management of carpal tunnel syndrome: a pilot randomized controlled trial.

Background: Carpal tunnel syndrome (CTS) is a prevalent entrapment neuropathy resulting in hand pain, numbness and/or weakness, which significantly impairs hand function in daily activities. Repetitive peripheral magnetic stimulation (rPMS) is a potential therapeutic option for focal peripheral nerve disease and may be beneficial for CTS treatment. We aimed to compare the effects of rPMS and conventional therapy in the management of CTS. Methods: A blinded assessor randomly assigned 24 participants with electrodiagnostically-confirmed mild or moderate CTS to either rPMS or conventional therapy. Both groups were briefed on disease progression and tendon-gliding exercises. In the intervention group, the rPMS protocol, five sessions of rPMS-with a frequency of 10 Hz, 10 pulses/train, and 100 trains/session-were performed over a period of 2 weeks, with three sessions in the first week and two sessions in the second week. At baseline and the end of the second week, the Boston Carpal Tunnel Questionnaire, pinch strength, and electrodiagnostic results were evaluated. Results: The rPMS group demonstrated significantly greater within-group improvement in symptom severity scores (2.3 vs. 1.6, p = 0.009) and pinch strength (10.6 lbs vs. 13.8 lbs, p < 0.001). Regarding electrodiagnostic parameters, sensory nerve action potential (SNAP) amplitude was significantly increased (8.7 µV vs. 14.3 µV, p = 0.002) within the group treated with rPMS. With conventional therapy, there were no statistically significant within-group differences. Multiple linear regression models showed that there were no significant differences in other outcomes in between-group comparisons. Conclusions: Five sessions of rPMS resulted in significant reduction in symptom severity, improvement in pinch strength and increase in SNAP amplitude. Future research should investigate the clinical utility of rPMS using a larger sample and longer treatment and follow-up durations.

Clinical predictors and electrodiagnostic characteristics in patients with Guillain-Barré syndrome with respiratory failure: a retrospective, matched case-control study.

BACKGROUND: Respiratory failure is a common complication of Guillain-Barré syndrome (GBS). This study aimed to determine the clinical predictors and electrodiagnostic (EDx) characteristics in patients with Guillain-Barré syndrome (GBS) with respiratory failure. METHODS: The retrospective study included 29 confirmed GBS cases with respiratory failure and age- (±5 years) and sex-matched controls (1:1). The dependent t-test and McNemar-Bowker test were used to analyse the continuous and categorical data, respectively. In addition, a multiple logistic regression analysis was used to analyse the predictive factors for respiratory failure. RESULTS: Among both cases and controls, the majority were male (72.4%), and the average age was 50.9 years. The data showed that patients with respiratory failure had higher GBS disability scores, lower motor power (≤3) of the hip flexors and ankle dorsiflexors, and experienced facial and bulbar palsy. In the multivariate analysis, the significant predictive factors were bulbar palsy (AOR 10.4 [95% CI [2.6-41.4]) and motor power of hip flexors ≤ 3 (AOR 31.4 [95% CI [3.1-314.5]). Patients with respiratory failure had lower compound muscle action potential amplitude of the ulnar and tibial nerves. The median, ulnar, and tibial nerve conduction studies were more likely to reflect inexcitability. The GBS subtypes in GBS patients with and without respiratory failure were not significantly different. CONCLUSIONS: Bulbar palsy and motor power of the hip flexors ≤ 3 were significant predictors for respiratory failure. The GBS subtypes in patients with and without respiratory failure were not significantly different.

The use of simple muscle strength tests to reflect body compositions among individuals with spinal cord injury.

STUDY DESIGN: A cross-sectional study. OBJECTIVES: To investigate the correlation between simple muscle strength tests (including handgrip test and upper limb loading during a seated push-up test [ULL-SPUT]) and body compositions among individuals with spinal cord injury (SCI). SETTING: A tertiary rehabilitation center. METHODS: Twenty-four participants with SCI (average age of 40 years) were cross-sectionally assessed using handgrip test, ULL-SPUT, and body compositions (including skeletal muscle mass, bone mineral content, and fat mass) using dual-energy X-ray absorptiometry scan. RESULTS: The handgrip data had low-to-moderate correlation to body compositions of the arms (rs = 0.474-0.515, p < 0.05), while the ULL-SPUT data were low-to-excellently correlated to all body compositions of the arms, legs, and trunk (rs, r = 0.467-0.921, p < 0.05). CONCLUSIONS: The findings extend clinical benefit of a SPUT apart from being a rehabilitation strategy to promote mobility of individuals with SCI. Simple measurement of the ULL-SPUT, which can be done using digital bathroom scales placed on a hard and even surface, appears to be strongly correlated with body compositions in a small sample of predominantly middle age, normal weight, men with paraplegia. More research is required to understand whether this test can be used clinically to assess body compositions in a more diverse SCI population, and whether it is responsive to changes in body compositions over time.

Prevalence and predictive factors for bilateral carpal tunnel syndrome by electrodiagnosis: A retrospective study.

INTRODUCTION: Carpal tunnel syndrome (CTS) is the most common compressive neuropathy. Patients who have unilateral symptoms are frequently found to have bilateral CTS by electrodiagnostic (EDx) study. We aimed to (a) study the prevalence and identify the predictive factors for bilateral CTS diagnosed by EDx; and (b) develop a model to predict bilateral CTS. METHODS: The retrospective clinical and EDx data of patients with CTS were collected and analyzed using the Chi-squared test and multiple logistic regression analysis. A model was fitted, and the best cutoff point determined. Calibration and discrimination performance of the model were performed. RESULTS: A total of 327 patients with a mean age of 50.0 years were enrolled. Most were women (82.6%), and the most common presenting symptom was hand numbness (93.6%). The median duration of symptoms was 60 days. The prevalence of bilateral CTS was 80.7%. In the multivariate analysis, the predictive factors for bilateral CTS were the presence of bilateral symptoms (AOR 6.7 [95%CI 3.1-14.3]), thenar muscle weakness (AOR 3.9 [95%CI 1.3-11.6]), and age ≥ 45 years (AOR 2.5 [95%CI 1.3-4.6]). The logistic regression model was fitted, and the best cutoff point determined. The area under the receiver operating curve (AUC) was 0.76. The respective optimism-corrected C index and Somers' D was 0.762 and 0.524. CONCLUSION: The prevalence of bilateral CTS was 80.7%. Our findings suggest bilateral CTS was predicted with adequate diagnostic accuracy by bilateral symptoms, age ≥ 45 years, and thenar muscle weakness.

Minimal clinically important difference of Gait Assessment and Intervention Tool (GAIT) in patients with sub-acute stroke.

BACKGROUND: The Gait Assessment and Intervention Tool (GAIT) is a well-accepted tool to determine gait characteristics in neurological patients. AIM: The aim of this study was to determine the minimal clinically importance difference (MCID) of the GAIT in sub-acute stroke patients. DESIGN: Prospective study. SETTING: An in- and out-patient rehabilitation clinic in a university hospital in Thailand. POPULATION: Patients with sub-acute stroke who had an ongoing rehabilitation between October 2017 to March 2019. METHODS: We used an anchor-based method to determine change in GAIT score needed to achieve MCID. Participants were dichotomized to 'no change group' or 'positive change group' based on different anchors of objective and subjective perceived changes in gait function after 4 weeks of rehabilitation. The groups were determined based on whether 1) participants achieved an increase in comfortable gait speed (CGS) of ≥ 0.06 m/s, 2) averaged Global Rating of Change (GROC) score was ≥+3 evaluated by two physiatrists 3) GROC score of was ≥+3 rated by the participants. The best cut-off point was the score which most successfully separated these two groups within the ROC curve. RESULTS: Thirty-one participants with sub-acute stroke (18 males, 13 female) completed both assessments. Their average age was 60.3±11.4 years. The best cut-off point were a 2.5- and 4-point improvements in GAIT score based on changes in CGS (AUC 0.76, 95% CI 0.58-0.95) and clinicians' perceived changes (AUC 0.88, 95% CI 0.76-1.00). Additionally, the best cut-off point was 1.5 (AUC 0.71 95% CI 0.31-1.00) when determined by participants' perception. All anchors yielded adequate discriminative ability. The positive likelihood ratio (LR) was in the range of 2.7-5.5 and the negative LR range was 0.1-0.3. CONCLUSIONS: A change in GAIT score should exceed 1.5, 2.5 and 4 to be considered MCID based on participants' GROC, CGS and Clinicians' GROC anchors. CLINICAL REHABILITATION IMPACT: This information will be useful for the determination of changes after rehabilitation and for tracking sub-acute stroke patients' progress.

Validity and Test-Retest Reliability of a Thai Stroke Physical Activity Questionnaire.

BACKGROUND AND OBJECTIVES: This study evaluated the validity and reliability of the Stroke Physical Activity Questionnaire (SPAQ), a Thai self-report questionnaire for assessing physical activity (PA) in participants with chronic stroke. METHODS: The validity of the SPAQ was tested by correlating PA data from the SPAQ with data obtained from a waist worn accelerometer which participants wore for seven days. The participants completed the SPAQ twice, one week apart and test-retest reliability was calculated using intraclass correlation coefficient. RESULTS: Forty-one participants, at least 3 months post-stroke (24 men and 17 women) were enrolled. The average age was 55.3 years (SD 11.9). Correlation coefficients of 0.58 and 0.57 were found between SPAQ and the accelerometer data for moderate PA and moderate to vigorous PA (MVPA), respectively. There was no significant correlation between light PA determined from SPAQ and accelerometer. The intraclass correlation coefficients were 0.56, 0.91 and 0.90 for light, moderate PA and MVPA, respectively. CONCLUSIONS: The validity of the SPAQ for moderate and MVPA was acceptable and the test-retest reliability of the SPAQ was excellent. This suggests the SPAQ is a useful tool for assessing moderate PA and MVPA among chronic stroke participants. However, it cannot be used to quantify light PA.

Incidence and predictive factors for developing vesicoureteric reflux in individuals with suprasarcral spinal cord injury: a historical cohort study.

STUDY DESIGN: A historical cohort study OBJECTIVES: The aim of the study was to examine the incidence of and predictive factors for VUR in individuals with suprasacral spinal cord injury (SCI). SETTING: Srinagarind Hospital, Khon Kaen University, Thailand METHODS: Medical records were reviewed for all individuals with SCI and neurogenic bladder admitted for urological check-up between 1996 and 2016. The primary outcome was the cumulative incidence of VUR. The statistical tests used included the Nelson-Aalen Estimator and Cox Proportional Hazard Ratio. Harrell's C concordance statistic was used to evaluate the discrimination ability of the predictive model. RESULTS: 293 participants with SCI (102 tetraplegic and 191 paraplegic) were included. Most participants were male (67%), and the median age was 52 years. The overall incidence of VUR was 7.5 cases per 100 person-years (95% CI, 6.15-9.4). In the multivariate analysis, the predictive factors for VUR were: (1) maximum detrusor pressure at first visit ≥ 75 cm of water (HRadj: 2.4 [95% CI: 1.4-4.1]); (2) indwelling urethral catheterization (IUC) (HRadj: 11.1 [95% CI: 3.9-31.7]) and clean intermittent catheterization (CIC) (HRadj: 6.5 [95% CI: 2.2-18.7]); (3) age ≥ 60 years at onset of SCI (HRadj: 1.7 [95% CI: 1.1-2.8]); and, (4) absence of antimuscarinic medication (HRadj: 3.8 [95% CI: 2.4-6.1]). The predictive model had an overall C-index of 0.78. CONCLUSIONS: The incidence of VUR was high up to 12 years after SCI. High maximum detrusor pressure, IUC, age ≥ 60 years and absence of antimuscarinic medication were predictive factors for VUR.

Ultrasonographic findings of shoulders in individuals with spinal cord injury.

Objective: To investigate shoulder ultrasonography findings in spinal cord injury (SCI) and identify factors associated with ultrasongraphic abnormalities.Design: A cross-sectional descriptive studySetting: Srinagarind hospital, ThailandParticipants: Spinal cord injury patients who attended the Srinagarind Hospital rehabilitation department.Outcome Measures: Baseline characteristics, physical examination, Physical Examination of the Shoulder Scale (PESS), and the ultrasonography of both shoulders of SCI patients were prospectively evaluated.Results: Ninety-one SCI patients were enrolled in this study, (56 with paraplegia and 35 with quadriplegia). Most patients in both groups had incomplete SCI. Wheelchairs were the most commonly used assistive devices in both groups. The top three ultrasonographic abnormalities in patients with quadriplegia were unilateral subdeltoid-subacromion bursitis (65.7%), unilateral supraspinatus tendinosis (45.7%), and unilateral biceps tendon effusion (37.2%). The most common abnormalities in those with paraplegia were unilateral subdeltoid-subacromion bursitis (64.3%), unilateral biceps tendon effusion (55.4%), and unilateral supraspinatus tendinosis (53.6%).Conclusions: Abnormal shoulder US findings were prevalent in individuals with SCI. The most common ultrasonographic abnormalities in patient with SCI was unilateral subdeltoid-subacromion bursitis.

Development and Preliminary Validation of a Stroke Physical Activity Questionnaire.

OBJECTIVE: The aim of the current study was to develop and then to determine preliminary validity of a physical activity questionnaire specifically designed for ambulatory, chronic stroke patients. METHODS: This cross-sectional study recruited 92 chronic stroke patients. In Phase I, the SPAQ was developed and its content validity index (CVI) determined. In Phase II, we examined (1) the concurrent validity of SPAQ vs. the International Physical Activity Questionnaire-Short Form (IPAQ-SF); (2) the convergent validity of SPAQ vs. the Functional Ambulation Category (FAC), vs. the six-minute walk test (6-MWT), vs. the timed up and go test (TUGT), vs. the Motricity Index, vs. the National Institutes of Health Stroke Scale (NIHSS), and vs. the Modified Rankin Scale (MRS); and (3) the discriminant validity of the SPAQ vs. the Montreal Cognitive Assessment (MoCA). The concurrent validity and convergent and divergent validity were analysed using Spearman's rank correlation coefficient. The agreement between the SPAQ and IPAQ-SF was assessed using the Kappa statistic. RESULTS: The SPAQ has 12 items in 3 main components which covers low (7 items), moderate (3 items), and vigorous (2 items) physical activity. The SPAQ had a CVI of 0.93. Spearman's correlation coefficient (rs) for SPAQ vs. IPAQ-SF was 0.53 (p < 0.001). The SPAQ yielded substantial agreement with the IPAQ-SF (Kappa = 0.65). For convergent validity, the SPAQ had a moderate correlation with the 6-MWT, MI, NIHSS, FAC, TUGT, and MRS (p < 0.05). For discriminant validity, the SPAQ was not correlated with the MoCA (rs = 0.061, p = 0.68). CONCLUSION: The SPAQ can be used to practically assess physical activity in chronic stroke patients, and it has acceptable psychometric properties which are comparable to other standard physical activity questionnaires. Future work should determine the validity of the SPAQ using an objective device such as an accelerometer.

Self-perceived and Actual Risk of Further Stroke in Patients with Recurrent Stroke or Recurrent Transient Ischemic Attack in Thailand.

BACKGROUND: The correct perception in patients of their future risk of recurrent stroke may lead to changes in behavior and to successful secondary prevention of stroke. The primary aim was to compare patients' perceived risk with the actual risk of further stroke. METHODS: This cross-sectional study was carried out in 2 tertiary hospitals in northeast Thailand. Self-perceived risk of further stroke was assessed by validated questionnaire and categorized as low, medium, or high. Actual risk was calculated using Stroke Prognosis Instrument II which classified patients into 3 risk groups: low, medium, and high. The level of agreement between perceived and actual risk was analyzed using the kappa statistic. RESULTS: One hundred forty patients with recurrent stroke or recurrent transient ischemic attack were enrolled (age 65.6 ± 11.3 years, mean ± standard deviation). Most patients wrongly estimated their risk of further stroke: 43.6% of patients underestimated and nearly one fifth (17.1%) overestimated their risk; the kappa coefficient was .08. Patients with hypertension and diabetes were more likely to underestimate their risk of recurrent stroke. The only characteristic found to be significantly associated with perceived high risk was the level of independence in activities of daily living: patients with Barthel index less than or equal to 60 were more likely to perceive themselves as having high risk for recurrent stroke. CONCLUSIONS: Most patients underestimated their risk for further stroke. Implementation of a comprehensive care program to communicate to patients their future risk of stroke and to modify their risk factors is warranted in Thailand.

Changes in heart rate variability with respect to exercise intensity and time during treadmill running.

BACKGROUND: Heart rate variability (HRV) arises from the complex interplay of sympathetic and parasympathetic autonomic regulation of heart rate. Ultra-low frequency (ULF) and very-low frequency (VLF) components of HRV play a crucial role in automatic HR controllers, but these frequency bands have hitherto largely been neglected in HRV studies. The aim of this work was to investigate changes in ULF and VLF heart rate variability with respect to exercise intensity and time during treadmill running. METHODS: RR intervals were determined by ECG in 21 healthy male participants at rest, and during moderate and vigorous-intensity treadmill running; each of these three tests had a duration of 45 min. Time dependence of HRV was investigated for moderate and vigorous running intensities by dividing the constant-speed stages into three consecutive windows of equal duration ([Formula: see text] 14 min), denoted [Formula: see text], [Formula: see text] and [Formula: see text]. ULF and VLF power were computed using Lomb-Scargle power spectral density estimates. RESULTS: For both the ULF and VLF frequency bands, mean power was significantly different between the resting, moderate and vigorous intensity levels (overall [Formula: see text]): mean power was lower for moderate vs. rest ([Formula: see text]), for vigorous vs. rest ([Formula: see text]), and for vigorous vs. moderate ([Formula: see text]). For both ULF and VLF and moderate intensity, mean power was significantly different between the three time windows (overall [Formula: see text] for ULF, overall [Formula: see text] for VLF): for ULF, mean power was lower for [Formula: see text] vs. [Formula: see text] ([Formula: see text]) and for [Formula: see text] vs. [Formula: see text] ([Formula: see text]); for VLF, mean power was lower for [Formula: see text] vs. [Formula: see text] ([Formula: see text]). For ULF and vigorous intensity, there was no significant difference in mean power between the three time windows (overall [Formula: see text]). For VLF and vigorous intensity, mean power was significantly different between [Formula: see text], [Formula: see text] and [Formula: see text] (overall [Formula: see text]): mean power was lower for [Formula: see text] vs. [Formula: see text] ([Formula: see text]) and for [Formula: see text] vs. [Formula: see text] ([Formula: see text]). CONCLUSIONS: The degree of HRV in terms of ULF and VLF power was found to decrease with increasing intensity of exercise. HRV was also observed to decrease over time, but it remains to clarify whether these changes are due to time itself or to increases in HR related to cardiovascular drift. For feedback control applications, attention should be focused on meeting performance targets at low intensity and during the early stages of exercise.

A new method for self-paced peak performance testing on a treadmill.

PURPOSE: Self-paced maximal testing methods may be able to exploit central mediation of function-limiting fatigue and therefore have potential to generate more valid estimates of peak oxygen uptake. The aim of this study was to investigate the feasibility of a new method for self-paced peak performance testing on treadmills and to compare peak and submaximal performance outcomes with those obtained using a non-self-paced ('computer-paced') method employing predetermined speed and slope profiles. METHODS: The proposed self-paced method is based upon automatic subject positioning using feedback control together with an exercise intensity which is driven by a predetermined, individualized work-rate ramp. RESULTS: Peak oxygen uptake was not significantly different for the computer-paced (CP) versus self-paced (SP) protocols: 4·38 ± 0·48 versus 4·34 ± 0·46 ml min-1 , P = 0·42. Likewise, there were no significant differences in the other peak and submaximal cardiopulmonary parameters, viz. peak heart rate, peak respiratory exchange ratio and the first and second ventilatory thresholds. Ramp duration for CP was longer than for SP: 494·5 ± 71·1 versus 371·3 ± 86·0 s, P = 0·00072. Concomitantly, the peak rate of work done against gravity was higher for CP: 264·8 ± 40·8 versus 203·8 ± 53·4 W, P = 0·0021. CONCLUSIONS: The self-paced approach was found to be feasible for estimation of the principal performance outcomes: the method was technically implementable, it was acceptable to the subjects and it showed good responsiveness. Further investigation of the self-paced method, with adjustment of the target ramp-phase duration or modification of the work-rate calculation equations, is warranted.

Knowledge of Stroke Risk Factors and Warning Signs in Patients with Recurrent Stroke or Recurrent Transient Ischaemic Attack in Thailand.

Stroke is a global burden. It is not known whether patients who are most at risk of stroke (recurrent stroke or recurrent transient ischaemic attack) have enough knowledge of stroke risk factors and warning signs. The aim of this study was to assess the knowledge of stroke risk factors and warning signs in this high-risk population. We performed a cross-sectional questionnaire-based study of patients with recurrent stroke or recurrent TIA admitted to Srinagarind Hospital and Khon Kaen Hospital, Thailand. A total of 140 patients were included in the study (age 65.6 ± 11.3 years [mean ± SD], 62 females). Using an open-ended questionnaire, nearly one-third of patients (31.4%) could not name any risk factors for stroke. The most commonly recognized risk factors were hypertension (35%), dyslipidemia (28.6%), and diabetes (22.9%). Regarding stroke warning signs, the most commonly recognized warning signs were sudden unilateral weakness (61.4%), sudden trouble with speaking (25.7%), and sudden trouble with walking, loss of balance, or dizziness (21.4%). Nineteen patients (13.6%) could not identify any warning signs. The results showed that knowledge of stroke obtained from open-ended questionnaires is still unsatisfactory. The healthcare provider should provide structured interventions to increase knowledge and awareness of stroke in these patients.

A method for predicting peak work rate for cycle ergometer and treadmill ramp tests.

BACKGROUND: Prediction of peak work rate (WRpeak) for incremental exercise testing (IET) is important to bring subjects to their maximal performance within the recommended 8-12 min. This study developed a novel method for prediction of WRpeak for IET on cycles and treadmills. METHODS: Peak metabolic equivalent of task (METpred) was predicted based on an existing non-exercise prediction formula, and then, predicted peak work rate (WRpred) was derived from separate formulae for the cycle and the treadmill. Eighteen healthy subjects were included. RESULTS: In males, there was no difference between WRpred versus WRpeak for both the cycle ergometer (277·7 versus 275·6 W, P = 0·70) and the treadmill (264·1 versus 260·5, P = 0·58). In females, there was no difference between WRpred versus WRpeak for the cycle ergometer (187·1 versus 188·3 W, P = 0·90), but a significant difference was found between WRpred versus WRpeak on the treadmill (178·6 versus 151·9 W, P<0·05). For males, the mean absolute percentage errors for WRpred versus WRpeak were 4·6% and 5·7% for the cycle and treadmill, respectively. For females, the errors were 12·2% and 20·8%. The algorithm was successful in achieving the required duration of 8-12 min in 33 of 36 cases. CONCLUSIONS: The peak work rate prediction protocol was accurate in male subjects for both the cycle and the treadmill. In female subjects, the method was accurate for the cycle, but systematically overpredicted the peak work rate on the treadmill. The protocol requires further adaptation for females on the treadmill.

Test-retest reliability and four-week changes in cardiopulmonary fitness in stroke patients: evaluation using a robotics-assisted tilt table.

BACKGROUND: Exercise testing devices for evaluating cardiopulmonary fitness in patients with severe disability after stroke are lacking, but we have adapted a robotics-assisted tilt table (RATT) for cardiopulmonary exercise testing (CPET). Using the RATT in a sample of patients after stroke, this study aimed to investigate test-retest reliability and repeatability of CPET and to prospectively investigate changes in cardiopulmonary outcomes over a period of four weeks. METHODS: Stroke patients with all degrees of disability underwent 3 separate CPET sessions: 2 tests at baseline (TB1 and TB2) and 1 test at follow up (TF). TB1 and TB2 were at least 24 h apart. TB2 and TF were 4 weeks apart. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and a real-time visual feedback system was used to guide the patients' exercise work rate during CPET. Test-retest reliability and repeatability of CPET variables were analysed using paired t-tests, the intraclass correlation coefficient (ICC), the coefficient of variation (CoV), and Bland and Altman limits of agreement. Changes in cardiopulmonary fitness during four weeks were analysed using paired t-tests. RESULTS: Seventeen sub-acute and chronic stroke patients (age 62.7 ± 10.4 years [mean ± SD]; 8 females) completed the test sessions. The median time post stroke was 350 days. There were 4 severely disabled, 1 moderately disabled and 12 mildly disabled patients. For test-retest, there were no statistically significant differences between TB1 and TB2 for most CPET variables. Peak oxygen uptake, peak heart rate, peak work rate and oxygen uptake at the ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) showed good to excellent test-retest reliability (ICC 0.65-0.94). For all CPET variables, CoV was 4.1-14.5 %. The mean difference was close to zero in most of the CPET variables. There were no significant changes in most cardiopulmonary performance parameters during the 4-week period (TB2 vs TF). CONCLUSIONS: These findings provide the first evidence of test-retest reliability and repeatability of the principal CPET variables using the novel RATT system and testing methodology, and high success rates in identification of VAT and RCP: good to excellent test-retest reliability and repeatability were found for all submaximal and maximal CPET variables. Reliability and repeatability of the main CPET parameters in stroke patients on the RATT were comparable to previous findings in stroke patients using standard exercise testing devices. The RATT has potential to be used as an alternative exercise testing device in patients who have limitations for use of standard exercise testing devices.

Identification of heart rate dynamics during moderate-to-vigorous treadmill exercise.

BACKGROUND: Heart rate can be used to prescribe exercise intensity for development and maintenance of cardiorespiratory fitness. The aim of this study was to identify the dynamics of heart rate response during moderate-to-vigorous treadmill exercise and to explore parameter dependencies with respect to time, intensity level and step-change direction. The focus was on simple approximate models for subsequent design of heart rate control systems. METHODS: 24 healthy, able-bodied male subjects each did two separate, 35-min tests on a treadmill, one at moderate and one at vigorous intensity. Each test had four individual upward and downward steps (1-4). Heart rate responses were modelled as first-order transfer functions with steady-state gain k and time constant [Formula: see text]. Models were estimated both for the overall testing periods and for individual step responses within each test. RESULTS: There were no significant differences in the overall mean values of k [24.3 vs. 24.1 bpm/(m/s), [Formula: see text]] and [Formula: see text] (55.7 vs. 59.5 s, [Formula: see text]) between the two intensity levels. The overall nominal gain for both conditions was [Formula: see text], 21.9-26.6 bpm/(m/s) (mean [Formula: see text] standard deviation, 95 % confidence interval), and the overall nominal time constant was [Formula: see text], 50.9-64.3 s. Analysis of models estimated from the individual steps revealed a significant difference in steady-state gain k for upward and downward steps [30.2 vs. 23.6 bpm/(m/s), [Formula: see text]], but no difference in time constant [Formula: see text] between these two directions (57.5 vs. 54.4 s, [Formula: see text]). For gain k, there was no significant main effect of intensity ([Formula: see text]) or intensity-time ([Formula: see text]) interactions, but there was a significant main effect of time ([Formula: see text]). Pairwise comparison with respect to time showed a significant difference between the upward steps at times 1 and 3 [33.0 vs. 27.3 bpm/(m/s), [Formula: see text]], but no significant difference between the downward steps at times 2 and 4 [24.4 vs. 22.8 bpm/(m/s), [Formula: see text]]. For time constant [Formula: see text], there were no significant main effects of intensity ([Formula: see text]) or time ([Formula: see text]), or intensity-time interactions ([Formula: see text]). CONCLUSIONS: The tight CI-bounds obtained, and the observed parameter dependencies, suggest that the overall nominal model with [Formula: see text] and [Formula: see text] might serve as the basis for design of a linear time-invariant (LTI) feedback system for real-time control of heart rate. Future work should focus on this hypothesis and on direct comparison of LTI and nonlinear/time-varying control approaches.

Submaximal cardiopulmonary thresholds on a robotics-assisted tilt table, a cycle and a treadmill: a comparative analysis.

BACKGROUND: The robotics-assisted tilt table (RATT), including actuators for tilting and cyclical leg movement, is used for rehabilitation of severely disabled neurological patients. Following further engineering development of the system, i.e. the addition of force sensors and visual bio-feedback, patients can actively participate in exercise testing and training on the device. Peak cardiopulmonary performance parameters were previously investigated, but it also important to compare submaximal parameters with standard devices. The aim of this study was to evaluate the feasibility of the RATT for estimation of submaximal exercise thresholds by comparison with a cycle ergometer and a treadmill. METHODS: 17 healthy subjects randomly performed six maximal individualized incremental exercise tests, with two tests on each of the three exercise modalities. The ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) were determined from breath-by-breath data. RESULTS: VAT and RCP on the RATT were lower than the cycle ergometer and the treadmill: oxygen uptake (V'O2) at VAT was [mean (SD)] 1.2 (0.3), 1.5 (0.4) and 1.6 (0.5) L/min, respectively (p < 0.001); V'O2 at RCP was 1.7 (0.4), 2.3 (0.8) and 2.6 (0.9) L/min, respectively (p = 0.001). High correlations for VAT and RCP were found between the RATT vs the cycle ergometer and RATT vs the treadmill (R on the range 0.69-0.80). VAT and RCP demonstrated excellent test-retest reliability for all three devices (ICC from 0.81 to 0.98). Mean differences between the test and retest values on each device were close to zero. The ventilatory equivalent for O2 at VAT for the RATT and cycle ergometer were similar and both were higher than the treadmill. The ventilatory equivalent for CO2 at RCP was similar for all devices. Ventilatory equivalent parameters demonstrated fair-to-excellent reliability and repeatability. CONCLUSIONS: It is feasible to use the RATT for estimation of submaximal exercise thresholds: VAT and RCP on the RATT were lower than the cycle ergometer and the treadmill, but there were high correlations between the RATT vs the cycle ergometer and vs the treadmill. Repeatability and test-retest reliability of all submaximal threshold parameters from the RATT were comparable to those of standard devices.

Feasibility of cardiopulmonary exercise testing and training using a robotics-assisted tilt table in dependent-ambulatory stroke patients.

BACKGROUND: We evaluated the feasibility of an augmented robotics-assisted tilt table (RATT) for incremental cardiopulmonary exercise testing (CPET) and exercise training in dependent-ambulatory stroke patients. METHODS: Stroke patients (Functional Ambulation Category ≤ 3) underwent familiarization, an incremental exercise test (IET) and a constant load test (CLT) on separate days. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and real-time visual feedback to guide the exercise work rate was used. Feasibility assessment considered technical feasibility, patient tolerability, and cardiopulmonary responsiveness. RESULTS: Eight patients (4 female) aged 58.3 ± 9.2 years (mean ± SD) were recruited and all completed the study. For IETs, peak oxygen uptake (V'O2peak), peak heart rate (HRpeak) and peak work rate (WRpeak) were 11.9 ± 4.0 ml/kg/min (45 % of predicted V'O2max), 117 ± 32 beats/min (72 % of predicted HRmax) and 22.5 ± 13.0 W, respectively. Peak ratings of perceived exertion (RPE) were on the range "hard" to "very hard". All 8 patients reached their limit of functional capacity in terms of either their cardiopulmonary or neuromuscular performance. A ventilatory threshold (VT) was identified in 7 patients and a respiratory compensation point (RCP) in 6 patients: mean V'O2 at VT and RCP was 8.9 and 10.7 ml/kg/min, respectively, which represent 75 % (VT) and 85 % (RCP) of mean V'O2peak. Incremental CPET provided sufficient information to satisfy the responsiveness criteria and identification of key outcomes in all 8 patients. For CLTs, mean steady-state V'O2 was 6.9 ml/kg/min (49 % of V'O2 reserve), mean HR was 90 beats/min (56 % of HRmax), RPEs were > 2, and all patients maintained the active work rate for 10 min: these values meet recommended intensity levels for bouts of training. CONCLUSIONS: The augmented RATT is deemed feasible for incremental cardiopulmonary exercise testing and exercise training in dependent-ambulatory stroke patients: the approach was found to be technically implementable, acceptable to the patients, and it showed substantial cardiopulmonary responsiveness. This work has clinical implications for patients with severe disability who otherwise are not able to be tested.