During aging processes, there is a range of functional changes, where we can highlight the disease related to the central nervous system, such as Alzheimer disease and others forms of dementia. This study investigated the effects of transcranial light emitting diode (LED) on cerebral blood flow in healthy elderly women analyzed by transcranial Doppler ultrasound (TCD) of the right and left middle cerebral artery and basilar artery. Twenty-five noninstitutionalized elderly women (mean age 72 years old), with a cognitive status >24, were assessed using transcranial Doppler ultrasound on two separate occasions: pre-irradiation and post-transcranial LED therapy (TCLT). Prior to this, they answered two questionnaires: the perceived stress scale and the general health questionnaire. TCLT (627 nm, 70 mW/cm(2), 10 J/cm(2)) was performed at four points of the frontal and parietal region for 30 s each, totaling 120 s two times per week for 4 weeks. Paired t-test results showed that there was a significant improvement after TCLT with increase in the systolic and diastolic velocity of the left middle cerebral artery (25 and 30%, respectively) and basilar artery (up to 17 and 25%), as well as a decrease in the pulsatility index and resistance index values of the three cerebral arteries analyzed (p < 0.05). TCD parameters showed improvement in the blood flow on the arteries analyzed. TCLT promoted a blood and vasomotor behavior of the basilar and middle cerebral arteries in healthy elderly women.
Excessive Aβ deposition in the brain is associated with the formation of senile plaques, and their diffuse distribution is related to Alzheimer's disease. Thirty rats (EG) were irradiated with light-emitting diode (photobiomodulation (PBM)) in the frontal region of the skull after being inoculated with the Aβ toxin in the hippocampus; 30 rats were used as the control group (CG). The analysis was conducted at 7, 14, and 21 days after irradiation. We observed a decreased in Aβ deposits in treated animals compared with animals in the CG. The behavioral and motor assessment revealed that the EG group covered a larger ground distance and explored the open field than the CG group on days 14 and 21 (p < 0.05). The EG group was statistically significant in the spatial memory test compared to the CG group on day 14. The use of PBM significantly reduced the presence of Aβ plaques and improved spatial memory and behavioral and motor skills in treated animals on day 21.
Muscle fatigue can influence the various mechanisms that regulate balance. Few studies have investigated the effects of trunk extensor muscle fatigue on postural control. The purpose of this study was to evaluate the impact of trunk extensor fatigue during a one-leg balance test in young and elderly adults, as well as to determine the time necessary to recover posture control after fatigue. A total of 36 subjects (18 elderly and 18 young adults) participated in the study. Subjects were tested on a force platform to assess the postural control parameters associated with center of pressure (COP) movements, before and after a fatiguing trunk extension-flexion exercise on a roman chair carried out to exhaustion. Post-fatigue effects and postural control recovery were investigated at different times in minutes (MIN): immediately post-fatigue (postIME), after 5 (rec5MIN), 10 (rec10MIN), and 20 min (rec20MIN). Elderly subjects had greater sway (P < 0.05) than young adults in all COP parameters. In both groups, there was an increase in postIME sway compared with pre-fatigue values for all COP parameters. However, the differences were significant only for the COP velocity parameter, with more pronounced effects in young adults that did not return to pre-fatigue values at the end of rec20MIN. The present study demonstrated a significant effect of trunk extensor muscle fatigue on postural control, which was more evident in young adults than in the elderly.
The aim of this study was to evaluate the changes in center of pressure (COP) movement in four time intervals (5, 10, 15 and 30 s) during a one-leg stance test performed by young and elderly adults. Twelve young adults (mean 20 years) and 12 elderly subjects (mean 68 years) participated in this study. The subjects performed three 30 s trials of an eyes open one-leg stance test on a force platform, in which the COP parameter was computed at four points in time from same original COP signal. Significant differences were found between the young and elderly adults (P< .007) only at the 10, 15 and 30 s intervals. For both groups, COP changes were significantly different between the 5 s time interval and other intervals (10, 15 and 30 s). In conclusion, these results pointed out that age-related difference in COP changes were time dependent. This suggests that the use of longer durations increases the possibility of distinguishing more subtle differences in postural strategy among different groups of subjects.
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