Effect of Light Therapy Among Peripheral Neuropathy Patients

This poster was presented at the Great Plains Honors Conference in Siloam Springs, Arkansas.https://scholarworks.uttyler.edu/student_posters/1012/thumbnail.jp

Influence of venous emptying on the reactive hyperemic blood flow response

BACKGROUND: Previous research indicates that venous emptying serves as a stimulus for vasodilation in the human forearm. This suggests the importance of recognizing the potential influence of venous volume on reactive hyperemic blood flow (RHBF) following occlusion. The purpose of this study was to examine the influence of venous emptying on forearm vascular function. METHODS: Forearm RHBF, venous capacitance and venous outflow were examined in 35 individuals (age = 22 ± 2 years), using mercury in-Silastic strain gauge plethysmography, at rest and following five minutes of upper arm occlusion using standard procedures (Control). In addition, the same measures were obtained following five minutes of upper arm occlusion preceded by two minutes of passive arm elevation (Pre-elevation). RESULTS: Average resting arterial inflow was 2.42 ± 1.11 ml·100 ml(-1)·min(-1). RHBF and venous capacitance were significantly greater during Pre-elevation compared to Control (RHBF; Pre-elevation: 23.76 ± 5.95 ml·100 ml(-1 )·min(-1 )vs. Control: 19.33 ± 4.50; p = 0.001), (venous capacitance; Pre-elevation: 2.74 ± 0.89 % vs. Control: 2.19 ± 0.97, p = 0.001). Venous outflow did not differ between the two conditions. CONCLUSION: Venous emptying prior to upper arm occlusion results in a significant greater RHBF response and venous capacitance. Recognition of the influence of venous volume on RHBF is particularly important in studies focusing on arterial inflow, and also provides further evidence for the interplay between the venous and arterial system

Biphasic responses of the brachial artery diameter following forearm occlusion: a blunted response in the elderly

BACKGROUND: The purpose was to examine the temporal response of the brachial artery diameter following 5 minutes of forearm occlusion in young men. A secondary objective was to compare the main features of the temporal pattern between young and old. METHODS: Sixteen young (28 ± 8 yrs) and fifteen older (85 ± 8 yrs) men underwent high-resolution ultrasonography of the brachial artery before and after five minutes of forearm occlusion. RESULTS: Following release of the pressure cuff the brachial artery diameter exhibits a temporal biphasic response. Initially, there is a significant reduction in brachial diameter (NIL) compared to baseline (BASE), followed by a rapid increase to a PEAK at 41 sec post release. When comparing the magnitude of the decrease in diameter and the Brachial Artery Flow Mediated Dilation (BAFMD) between Young and Old, older subjects demonstrated a blunted response (Magnitude of Decrease: Young: 2.0%; Old: 0.4%, p = 0.015, and BAFMD: Young: 7.7%; Old: 2.3%, p = 0.001). Finally, a significant relationship was noted between the magnitude of decrease and BAFMD (r = -0.44, p = 0.04). CONCLUSION: Examination of the temporal response of the brachial artery diameter following 5 minutes of forearm occlusion reveals a biphasic pattern in all participants. Specific features of this pattern are blunted in older adults compared with younger subjects. Finally, the magnitude of the drop in diameter following forearm occlusion correlates with the magnitude of the BAFMD

Effects Of A 4-week Vibration-induced Hamstrings Fatigue Intervention On Quadriceps Weakness After ACL Reconstruction

Arthrogenic muscle inhibition (AMI) results from an inability to voluntarily activate all motor units in the quadriceps due to ongoing neuronal inhibition. This may be due to changes in small diameter afferent activity that increase the excitability of the flexor withdrawal pathway, causing over-excitation of the hamstrings and reciprocal inhibition of the quadriceps. Reciprocal inhibition of the quadriceps from Ia afferents of the hamstrings may be reduced with prolonged muscle vibration of the hamstrings via fatigue of the intrafusal muscle fibers. PURPOSE: To determine the effects of vibration-induced hamstring fatigue on AMI after ACL reconstruction (ACLr). METHODS: Seven adults (28.7 ± 8.2 yrs) with unilateral ACLr (time since surgery: 19.4 ± 9.7 months) were recruited. Participants received a 4-week long (3x/week) training program. Vibration-induced fatigue of the hamstrings consisted of 20 minutes of prolonged vibration applied directly to the hamstrings. Then, a cuff was placed on the proximal thigh and inflated to 150 mmHg to trap the metabolites in the muscle, and maintain hamstrings fatigue; during which participants performed four sets of 15 reps at 30% RM unilateral knee extension (KE). Quadriceps strength and quadriceps inhibition were assessed before and after the intervention using KE 1-repitition maximum (RM) normalized to body weight, and the central activation ratio (CAR) measured by a superimposed burst. The co-activation of the hamstrings was assessed using hamstring EMG during KE. Paired t-tests were used to examine the effect of prolong vibration on KE strength, quadriceps CAR, and hamstrings co-activation before and after the intervention. RESULTS: KE strength increased significantly by 38.5% (from 0.45 ± 0.1 to 0.62 ± 0.2 %BW, P =0.004); quadriceps CAR also increased significantly by 5.8% (from 93 ± 0.1% to 98 ± 0.8%, P=0.02). Finally, co-activation decreased by 34% (from 12 ± 1.3% to 8 ± 0.9%, P=0.03). CONCLUSION: These results suggest that quadriceps weakness may be due to over excitation of the hamstrings which results in reciprocal inhibition of the quadriceps. Vibration-induced hamstrings fatigue can be used as a rehabilitation strategy to restore normal quadriceps function following ACLr by reducing the hamstrings over-excitability and restoring full quadriceps activation

Impact of Tai Chi on Peripheral Neuropathy Revisited: A Mixed-Methods Study

Exercise may be beneficial to older persons living with peripheral neuropathy (PN), but maintaining an exercise program is challenging. After participating in a 12-week tai chi (TC) study, 12 participants requested classes continue. A mixed-methods design was used to explore long-term engagement of older persons with bilateral PN enrolled in a TC class for 18 months beyond the original 3-month study. Pre- and posttest measures of functional status and quality of life (QOL) were conducted. Focus groups were held after 18 months of twice-weekly classes. Psychosocial support was critical to participants’ long-term commitment to exercise. Participants reported, and objective assessments confirmed, increased strength, balance, and stamina beyond that experienced in the original 12-week study. Changes in QOL scores were nonsignificant; however, qualitative data supported clinical significance across QOL domains. Results from this study support psychosocial and physical benefits of TC to older persons

Effect of Tai Chi on Vascular Function Among Patients with Peripheral Neuropathy

Foot pain due to Peripheral Neuropathy (PN) is one of the factors affecting walking ability. It has been reported that diminished vascular function contributes to a decrease in physical function in individuals with PN. Microvascular disturbances have been reported in humans with neuropathic pain. Tai Chi, a Chinese conditioning exercise, has been associated with enhanced endothelial function. However, the effect of Tai Chi training on microvascular function in patients with PN has not been studied. This study aimed to assess the effects of Tai Chi on vascular function (i.e., vascular reactivity) and functional exercise capacity among patients with PN. Thirty-seven participants (men = 21, women = 16) were randomly assigned to either Tai Chi exercise (Ex, n = 20, age: 71 ± 9.50 years) or control group (Con, n = 17, age: 75 ± 9.02 years). Exercise training consisted of 12-week progressive Tai Chi (i.e., Yang Style), offered 3 times per week, 60 minutes sessions. The Con group did not participate in any exercise activity. Before and after training, vascular function [finger tip digital thermal monitoring of vascular reactivity] and functional exercise capacity [Six-Minute Walk test (6MW)] were evaluated. The Ex group experienced a significant 25% increase in vascular reactivity index from baseline [1.93 ± 0.43 to 2.41 ± 0.47, (P \u3c 0.05)]. In addition, the 6MW test increased significantly in the Ex group by 28% [pre = 392 ± 93; post = 503 ± 105 m, (P \u3c 0.05)]. In the control group no significant changes were observed in either vascular function [1.83 ± 0.43 to 1.81 ± 0.37] or in the 6MW test [393 ± 142 to 398 ± 149 m]. Participants experienced no complications and/or falls as a result of the intervention. These findings demonstrated that in patients with PN, a 12-week progressive Tai Chi exercise program was capable of increasing not only vascular function, specifically vascular reactivity index, but also of increasing the distance covered during the 6MW test. Clearly, this study underlies the importance of Tai Chi as an effective and safe exercise intervention suitable for patients with PN

Tai Chi Exercise on Muscle Strength and Physical Function in Peripheral Neuropathy Patients

This poster was presented at the American College of Sports Medicine\u27s (ACSM) 63rd Annual Meeting and World Congresses, Boston, MA.https://scholarworks.uttyler.edu/fac_posters/1016/thumbnail.jp