Electromyographic latency of postural evoked responses from the leg muscles during EquiTest Computerised Dynamic Posturography: Reference data on healthy subjects

Abstract Objective To investigate the effect of visual fatigue caused by smart phone on the balance function. Subjects and Methods Forty subjects divided into 2 groups were included in the present study . Group I, twenty normal healthy subjects with mean age of 28.8 years. Group II, twenty subjects with a clinical diagnosis of peripheral vestibular disorder with mean age of 38.85years. They were subjected to a computer vision syndrome questionnaire (CVS-Q) , occulomotor tests of videonystagmography (VNG) and sensory organization test (SOT) of computerized dynamic posturography (CDP) before and after visual fatigue induction. Results Significant differences existed between C5, 6 and composite scores in group I and in C4 and composite scores in group II after visual fatigue induction. However, there was no significant difference between occulomotor tests in both groups after visual fatigue induction. Conclusions The smart phone use can affect the balance function in healthy subjects and augment the deficit in those with balance problem. Reducing visual fatigue should be considered through various procedures as taking proper rest, adjusting the brightness of screen, avoid any wrong posture and using filters if possible.

Download Full-text

Computerised dynamic posturography

Indian Journal of Otolaryngology and Head & Neck Surgery ◽

10.1007/bf03048071 ◽

1996 ◽

Vol 48 (2) ◽

pp. 163-165

Author(s):

Anirban Biswas

Keyword(s):

Dynamic Posturography ◽

Computerised Dynamic Posturography

Download Full-text

More Impaired Dynamic Ventilatory Muscle Oxygenation in Congestive Heart Failure than in Chronic Obstructive Pulmonary Disease

Journal of Clinical Medicine ◽

10.3390/jcm8101641 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1641 ◽

Cited By ~ 1

Author(s):

Ming-Lung Chuang ◽

I-Feng Lin ◽

Meng-Jer Hsieh

Keyword(s):

Heart Failure ◽

Chronic Obstructive Pulmonary Disease ◽

Healthy Subjects ◽

Tissue Oxygenation ◽

Muscle Oxygenation ◽

Chronic Obstructive ◽

Obstructive Pulmonary Disease ◽

Leg Muscles ◽

Patient Groups ◽

Ventilatory Muscles

Patients with chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF) often have dyspnea. Despite differences in primary organ derangement and similarities in secondary skeletal muscle changes, both patient groups have prominent functional impairment. With similar daily exercise performance in patients with CHF and COPD, we hypothesized that patients with CHF would have worse ventilatory muscle oxygenation than patients with COPD. This study aimed to compare differences in tissue oxygenation and blood capacity between ventilatory muscles and leg muscles and between the two patient groups. Demographic data, lung function, and maximal cardiopulmonary exercise tests were performed in 134 subjects without acute illnesses. Muscle oxygenation and blood capacity were measured using frequency-domain near-infrared spectroscopy (fd-NIRS). We enrolled normal subjects and patients with COPD and CHF. The two patient groups were matched by oxygen-cost diagram scores, New York Heart Association functional classification scores, and modified Medical Research Council scores. COPD was defined as forced expired volume in one second and forced expired vital capacity ratio ≤0.7. CHF was defined as stable heart failure with an ejection fraction ≤49%. The healthy subjects were defined as those with no obvious history of chronic disease. Age, body mass index, cigarette consumption, lung function, and exercise capacity were different across the three groups. Muscle oxygenation and blood capacity were adjusted accordingly. Leg muscles had higher deoxygenation (HHb) and oxygenation (HbO2) and lower oxygen saturation (SmO2) than ventilatory muscles in all participants. The SmO2 of leg muscles was lower than that of ventilatory muscles because SmO2 was calculated as HbO2/(HHb+HbO2), and the HHb of leg muscles was relatively higher than the HbO2 of leg muscles. The healthy subjects had higher SmO2, the patients with COPD had higher HHb, and the patients with CHF had lower HbO2 in both muscle groups throughout the tests. The patients with CHF had lower SmO2 of ventilatory muscles than the patients with COPD at peak exercise (p < 0.01). We conclud that fd-NIRS can be used to discriminate tissue oxygenation of different musculatures and disease entities. More studies on interventions on ventilatory muscle oxygenation in patients with CHF and COPD are warranted.

Download Full-text

Effect of induced leg muscle fatigue on exertional dyspnea in healthy subjects

Journal of Applied Physiology ◽

10.1152/japplphysiol.00393.2014 ◽

2015 ◽

Vol 118 (1) ◽

pp. 48-54 ◽

Cited By ~ 11

Author(s):

Pramod Sharma ◽

Norman R. Morris ◽

Lewis Adams

Keyword(s):

Healthy Subjects ◽

Knee Extension ◽

Respiratory Drive ◽

Exertional Dyspnea ◽

Leg Muscles ◽

Test Speed ◽

Numerical Scale ◽

Ventilatory Drive ◽

Afferent Information ◽

Experimentally Induced

The genesis of dyspnea is complex. It appears to be related to central respiratory drive although prevailing leg fatigue could independently potentiate dyspnea. We hypothesized that experimentally induced leg fatigue generates more intense exertional dyspnea for a given level of ventilatory drive. Following familiarization, 19 healthy subjects (32.2 ± 7.6 yr; 11 men) performed a 5-min treadmill test (speed: ∼4 km/h; grade: ∼25%) on two separate days randomized between control (C) and experimentally induced leg fatigue (E) achieved by repeated knee extension against 40% body weight until task failure. Oxygen uptake (V̇o2, l/min), carbon dioxide output (V̇co2, l/min), ventilation (V̇e, l/min), and respiratory rate (fR) were measured breath by breath. Heart rate (HR) and perceived dyspnea intensity (0–10 numerical scale) were recorded continuously. Data were averaged over 30-s intervals. Exertional dyspnea during E was statistically significantly higher (E vs. C: 4.2 ± 0.2 vs. 3.4 ± 0.2, P < 0.001) and accompanied by a significant increase in V̇e (E vs. C: 61.7 ± 3.7 vs. 55.3 ± 2.8, P = 0.005) and fR (E vs. C: 26.7 ± 1.0 vs. 24.2 ± 1.3, P = 0.036). Dyspnea following E remained significantly higher after allowing for the V̇e confound (ANCOVA, P = 0.003). V̇o2, V̇co2, and HR were not significantly different between two conditions. However, the slopes for dyspnea vs. V̇o2 and dyspnea vs. V̇e were similar between E and C, which suggested that gain in dyspnea per unit change in V̇o2 or V̇e was not altered by leg fatigue. These findings support the hypothesis that the intensity of exertional dyspnea is exacerbated by peripheral afferent information from fatigued leg muscles.

Download Full-text