Effects of exercise on somatosensory-evoked potentials

The aim of this study was to investigate the effect of acute and regular exercise on somatosensory-evoked potentials (SEP). The study group was designed as 9 female and 7 male volleyball players, and the control group as 9 female and 7 male sedentary students. The P1 and P2 latency and amplitude values were measured by tibial nerve stimulation on both lower extremities in the study groups before and after exercise on a treadmill. Intra-group comparison was made to evaluate the acute effects of exercise, and inter-group comparison for the chronic effects of it. Statistically significant difference was determined in pre-exercise right P2 amplitudes and post-exercise left P2 latencies of female volleyball players and sedentary girls. There was significant difference between only the pre-exercise left P2 latency when comparison was made between the sportsmen and sedentary male subject groups. There were significant differences between the pre-exercise left P1 and P2 latency values of sportswomen and right P2 amplitudes of sedentary female subjects. There was no significant difference between left P2 latency values of sportsmen and sedentary male subjects. In conclusion, it was determined that acute and regular exercise shortened the latency of sensory-evoked potentials while decreasing their amplitudes. When evaluating the sensory-evoked potentials in electrophysiology laboratories, the exercise capacity and physical activity levels of the subjects should be considered.     

EFFECTS OF EXERCISE ON VISUAL EVOKED POTENTIALS

The aim of this study was to investigate the effects of acute or habitual exercise on visual evoked potentials (VEP). The study group consisted of 9 female and 7 male volleyball players and the control group contained 9 female and 7 male students who were not involved in any sportive activity. The N75, P100, and N145 latency and amplitudes were measured before and after exercise. Intragroup comparison was made to evaluate the acute effects and intergroup comparison for the chronic effects of exercise. Significant differences were noted between athletes and the sedentary subjects in terms of pre-exercise left-N145 latencies and amplitudes and left -P100 amplitudes. Right-eye N145 latencies of inactive female subjects obtained before and after exercise were also statistically different. The results suggest that acute and habitual exercise affects the VEP responses independent from the body temperature and other physiological parameters. Small sized pre-exercise P100 amplitudes in the athletes can be attributed to the effect of rapid visual-activity-demanding sports on the central nervous system. Visual evoked potentials maybe used as neurophysiological criteria in defining the performance of an athlete.     

Effects of exercise on visual evoked potentials

The aim of this study was to investigate the effects of acute or habitual exercise on visual evoked potentials (VEP). The study group consisted of 9 female and 7 male volleyball players and the control group contained 9 female and 7 male students who were not involved in any sportive activity. The N75, P100, and N145 latency and amplitudes were measured before and after exercise. Intragroup comparison was made to evaluate the acute effects and intergroup comparison for the chronic effects of exercise. Significant differences were noted between athletes and the sedentary subjects in terms of pre-exercise left-N145 latencies and amplitudes and left -P100 amplitudes. Right-eye N145 latencies of inactive female subjects obtained before and after exercise were also statistically different. The results suggest that acute and habitual exercise affects the VEP responses independent from the body temperature and other physiological parameters. Small sized pre-exercise P100 amplitudes in the athletes can be attributed to the effect of rapid visual-activity-demanding sports on the central nervous system. Visual evoked potentials maybe used as neurophysiological criteria in defining the performance of an athlete.     

The sympathetic skin response habituation in sedentary subjects and sportsmen

The aim of the present study was to investigate the habituation rates of the sympathetic skin response (SSR) in sedentary subjects and trained sportsmen. A total of 52 voluntary male students (30 sedentary subjects and 22 trained sportsmen) participated in the experiment. SSR was recorded with the contralateral electrical stimulation of the ulnar nerve (of the upper extremities). In order to initiate the SSRs, 16 square-wave consecutive electrical shock stimuli were presented to each subject over the left ulnar nerve. In 52 subjects, 16 stimuli were applied at random time intervals (20-50 s). In sedentary subjects, the mean amplitude of the SSRs decreased from 4.83 +/- 0.36 mV at the first stimulus, to 0.80 +/- 0.12 mV at the 16th stimulus. In trained sportsmen, the mean amplitude of the SSRs decreased from 3.95 +/- 0.51 mV at the first stimulus, to 0.80 +/- 0.17 mV at the 16th stimulus. In the sedentary subjects, at the S1-S9 stimuli, the mean amplitudes of SSRs were higher than those of trained sportsmen. Depending upon these findings we can say that the trained sportsmen showed a more rapid habituation than sedentary subjects. In these processes, changes of amplitude and latency values reflect changes in amount of neuronal activation. Amplitude reflects the amount of neuronal activation, which is concerned with number of neuronal populations. Neuroplasticity, known as the habituation of the brain, is the adaptation of autonomic nervous system, which can be reflected by SSRs.     

Comparison of the effects of acute and regular exercise on intraocular pressure in Turkish athlete and sedentarians

The aim of this study was to investigate the changes that take place in IOP in athletes and people leading sedentary lives subjected to aerobic and anaerobic exercise and how chronic exercise could affect these changes. The study included 20 sportsmen (Group 1), and 20 people leading sedentary lives (Group 2). The intensity of the exercise for both groups was determined according to the Karvonen protocol and executed as an aerobic exercise program involving running on a treadmill for 30 min. Subjects in both groups were subjected to anaerobic exercise according to the Wingate test protocol for 30 s. The intraocular pressure of all subjects before exercise and after aerobic and anaerobic exercise were measured. The IOP before and after exercise aerobic and anaerobic were evaluated by the Willcoxon test whereas the right and left IOP before exercise and after the aerobic and anaerobic exercise programs in both groups were evaluated using the Mann Whitney U test. p values of <.05 were considered significant. Significant differences were found when the pre-exercise and post-aerobic and anaerobic exercise IOPs of the groups were compared (p < .05). Comparison of the post-anaerobic and aerobic exercise revealed a fall in the IOPs of the subjects after the aerobic exercise (p < .01). In this study, exercise was found to lead to a fall in the IOP in both sportsmen and those leading sedentary lives with the fall less apparent under anaerobic conditions than under aerobic conditions. In conclusion, therefore, it can be said that in those with an increased intraocular pressure, regular, moderately intense aerobic exercise rather than short-lived intense exercise could be more useful.     

COMPARISON OF THE EFFECTS OF ACUTE AND REGULAR EXERCISE ON INTRAOCULAR PRESSURE IN TURKISH ATHLETE AND SEDENTARIANS

The aim of this study was to investigate the changes that take place in IOP in athletes and people leading sedentary lives subjected to aerobic and anaerobic exercise and how chronic exercise could affect these changes. The study included 20 sportsmen (Group 1), and 20 people leading sedentary lives (Group 2). The intensity of the exercise for both groups was determined according to the Karvonen protocol and executed as an aerobic exercise program involving running on a treadmill for 30 min. Subjects in both groups were subjected to anaerobic exercise according to the Wingate test protocol for 30 s. The intraocular pressure of all subjects before exercise and after aerobic and anaerobic exercise were measured. The IOP before and after exercise aerobic and anaerobic were evaluated by the Willcoxon test whereas the right and left IOP before exercise and after the aerobic and anaerobic exercise programs in both groups were evaluated using the Mann Whitney U test. p values of <.05 were considered significant. Significant differences were found when the pre-exercise and post-aerobic and anaerobic exercise IOPs of the groups were compared (p < .05). Comparison of the post-anaerobic and aerobic exercise revealed a fall in the IOPs of the subjects after the aerobic exercise (p < .01). In this study, exercise was found to lead to a fall in the IOP in both sportsmen and those leading sedentary lives with the fall less apparent under anaerobic conditions than under aerobic conditions. In conclusion, therefore, it can be said that in those with an increased intraocular pressure, regular, moderately intense aerobic exercise rather than short-lived intense exercise could be more useful.     

The interaction between sex and click polarity in brain-stem auditory potentials evoked from control subjects of Oriental and Caucasian origin

Brain-stem auditory evoked potentials (BAEPs) were performed on 30 male and 30 female young normal Oriental subjects, using both condensation and rarefaction stimulation. The effects of sex and click polarity on the BAEP latencies and amplitudes were studied. Females had shorter absolute and interpeak latencies and higher absolute amplitudes than the males. These sex-related BAEP differences were independent of the click polarity. Rarefaction clicks produced shorter wave I latency and longer I-III interpeak latency, but the differences were significant in the female only. The polarity-related BAEP amplitude differences were essentially independent of the sex. BAEPs performed on 60 sex- and age-matched young Caucasian subjects produced similar results. The importance of establishing control BAEP values according to the sex and click polarity is emphasised.     

EFFECT OF ACUTE SUBMAXIMAL EXERCISE ON INTRAOCULAR PRESSURE IN ATHLETES AND SEDENTARY SUBJECTS

The existing literature is controversial regarding the relationship between physical fitness and intraocular pressure (IOP). Therefore, the effects of acute submaximal exercise on IOP were compared in athletes and sedentary subjects. Acute exercise increased IOP in male athletes, but had no effect in sedentary men. Also, it decreased IOP in sedentary women, but had no effect in female athletes. Sex and physical fitness both were significant factors influencing the changes in IOP due to exercise. These results suggest that acute dynamic exercise is useful to decrease IOP in sedentary women, but not in male athletes. These results may help glaucoma screeners.     

Effect of acute submaximal exercise on intraocular pressure in athletes and sedentary subjects

The existing literature is controversial regarding the relationship between physical fitness and intraocular pressure (IOP). Therefore, the effects of acute submaximal exercise on IOP were compared in athletes and sedentary subjects. Acute exercise increased IOP in male athletes, but had no effect in sedentary men. Also, it decreased IOP in sedentary women, but had no effect in female athletes. Sex and physical fitness both were significant factors influencing the changes in IOP due to exercise. These results suggest that acute dynamic exercise is useful to decrease IOP in sedentary women, but not in male athletes. These results may help glaucoma screeners.     

Absence of facilitation or depression of motor evoked potentials after contralateral homologous muscle activation

We have previously described post-exercise facilitation and post-exercise depression of motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS). To determine the presence of post-exercise facilitation after exercise of a contralateral muscle, MEPs were recorded from the resting right extensor carpi radialis (ECR) muscle while the left ECR muscle was activated, then immediately after brief left ECR activation, and, finally, immediately after brief right ECR activation. We repeated the experiment using the first dorsal interosseous (FDI) muscle. To determine the presence of post-exercise depression after exercise of a contralateral muscle, MEPs were recorded from the right ECR after prolonged exercise of the left ECR, followed by right ECR recording after its fatigue. The mean MEP amplitudes from the right ECR and the right FDI after brief activation were 187% and 266% of their pre-exercise values, respectively. There were no significant changes in MEPs recorded from the right ECR or FDI muscles during or immediately after brief activation of their left counterparts. The mean amplitude of MEPs recorded from the right ECR after it fatigued was approximately half the pre-exercise value, but there was no significant change in MEPs recorded from the right ECR after prolonged exercise of the left ECR. Therefore, neither post-exercise facilitation nor post-exercise depression occurred after contralateral homologous muscle exercise.     

Correlations between event-related potential components and nitric oxide in maximal anaerobic exercise among sportsmen trained at various levels

Physical exercise has influence on all organs except its effects on the central nervous system have not been fully elucidated. This study attempts to determine whether the degree of training could affect the response to physical stress by comparing the three groups of males in different levels of the physical fitness. Serum samples from high (n = 11), moderate (n = 10), and low physical activity sportsmen (n = 10) were collected to determine nitrite/nitrate levels before and after carrying out an anaerobic maximal exercise test. An "oddball paradigm" of auditory stimuli was used to evoke the N200 and P300 before and after the exercise. The amplitude of the N200 decreased significantly after anaerobic maximal exercise compared to the values of the recorded pre-exercise at Fz area in high physical activity group. There was a negative correlation between event-related potentials component and both nitrite/nitrate serum level changes and the heart rate changes in low physical activity subjects. However, in high and moderate physical activity groups, these relationships were positive.     

The effect of sex differences on event-related potentials in young adults.

Female/male cognitive differences have been studied for some time; however, such differences in Turkish population is unknown. Evoked potentials (EPs) of the brain have been applied as an index of information processing in a wide variety of normal and cognitive impaired subjects. Scalp event-related potentials (ERP) evoked by auditory stimuli were recorded in 20 male and 18 female neurologically and audiologically normal young Turkish subjects of 18-25 years (Av. 20.6) of age. Standard auditory "Oddball" paradigm involving simple discrimination task of concentrating on infrequent (target) stimulus and ignoring frequent (non-target) stimulus was employed. EEG activity was recorded at the Fz, Cz, Pz and Oz electrode sites of the 10-20 system using Ag/AgCl electrodes. Wave forms were collected and averaged off-line by a Pentium 100 computer, which also controlled the stimulus presentation. In general, significant main effects of gender and electrode site on evoked potential components were found. The interpeak amplitudes N1-P2 and N2-P3 were higher in the male subjects than in the female subjects at Cz. N2-P3 were higher in the male subjects than in the female subjects at Oz. The latencies of N1, P2, N2, P3 components were not different between both sex. For both sexes we found that N1-P2 amplitude was higher at Fz and Cz than Pz and Oz. N2-P3 amplitude was higher at Fz than Oz for only female subject. In male subjects, latency of N2 was longer at Fz than Oz. There were no significant differences in the latencies of N1, P2, and P3 components between electrode sites in both sexes. We suggest that ERP components could be affected by sex, electrode site, and cognitive performance.     

Hemispheric differences for visual evoked potentials from checkerboard stimuli

Visual evoked potentials (VEPs) were elicited in right-handed male subjects with an alternating checkerboard pattern stimulus presented to either the left or right visual half-field. The sizes of the individual checks in different conditions were 0.25, 0.5, 2.0, or 4.0 cycles/degree of visual angle. The amplitude of the P100 VEP decreased while peak latency increased as check size decreased across both visual field conditions. Left hemisphere responses demonstrated significantly larger P100 amplitudes compared to the right hemisphere responses, although the interaction between hemisphere and stimulus size was not significant. No hemispheric effects of P100 latency were observed. The results suggest that the left hemisphere is engaged more than the right hemisphere for the sensory analysis of visual stimuli composed of straight edges over a wide range of spatial frequencies.     

Combined electrophysiological assessment of the visual system in central serous retinopathy

Six subjects suffering from idiopathic central serous retinopathy were examined during the acute phase using a battery of neurophysiological tests. The records (using skin electrodes) included the electro-oculogram (EOG), the white light electroretinogram (ERG) during various stages of dark and light adaptation, and the flash and pattern reversal visual evoked potentials. Results obtained from the affected eye were compared with those from the healthy eye. The values of the healthy eye were not significantly different from our normal control group. The EOGs of the affected eyes were not significantly different from those of the healthy eyes. The 'a' wave of the ERG during light adaptation was significantly (P less than 0.05) smaller in the affected eye. The amplitudes of the other components and the latencies of all components were not affected. The latency of the PR-VEP of the affected eye in all subjects was prolonged in comparison with the unaffected eye. In 3 subjects the latency was prolonged by more than 2 S.D.s compared with our control group. The amplitude of the PR-VEP in 5 of our 6 subjects was slightly but significantly (P less than 0.02) smaller in the affected eye. There was no correlation between amplitude and latency changes.     

Differences of latencies and amplitudes of brain stem evoked potentials in subgroups of a normal material.

Brain stem auditory evoked potentials have been recorded in 40 normal subjects aged 13--48 years, by stimulating monaurally with random stimulus interval. The male subjects have latencies of the waves III-VII, which are significantly longer than female subjects (P less than 0.0005), the elongation increasing from 0.09 to 0.44 msec from wave III to VII. The female subjects have amplitudes significantly higher than male subjects, although the variations are very wide. No difference in latencies from tall versus short subjects is found, as well as no significant difference in latencies between subgroups of older and younger subjects of the material. It is found necessary to have different normal values for the two sexes.     

Differences of latencies and amplitudes of brain stem evoked potentials in subgroups of a normal material

Brain stem auditory evoked potentials have been recorded in 40 normal subjects aged 13–48 years, by stimulating monaurally wiht random stimulus interval. The male subjects have latencies of the waves III-VII, which are significantly longer than female subjects ( P < 0.0005), the elongation increasing from 0.09 to 0.44 msec from wave III to VII. The female subjects have amplitudes significantly higher than male subjects, although the variations are very wide. No difference in latencies from tall versus short subjects is found, as well as no significant difference in latencies between subgroups of older and younger subjects of the material. It is found necessary to have different normal values for the two sexes.     

Attenuated SEPs with no latency shifts in a family with hereditary spastic paraplegia

Five siblings with hereditary spastic paraplegia of autosomal-dominant inheritance were studied with somatosensory evoked potentials. Somatosensory evoked potentials were recorded from Cz', T12, and the left popliteal fossa following left posterior tibial nerve stimulation. The latency and amplitude of the corresponding potentials (i.e., P37, N20, and N7) were compared with normal values obtained from age- and height-matched controls. There was no significant difference in the values of N7, suggesting an intact afferent peripheral pathway; in contrast, the amplitudes of P37 and N20 were decreased with normal latencies. The degree of amplitude decrease correlated with the severity of vibration sense impairment in the lower limbs. These results appear to support selective axonopathy of the centrally directed axons of the dorsal root ganglion cells. Furthermore, our results suggest that different degrees of dorsal column involvement in hereditary spastic paraplegia can cause different types of somatosensory evoked potential abnormalities, namely, attenuated amplitudes with no latency shifts, as recorded in this family, and the prolonged latencies, as reported previously.     

Cervical vestibular-evoked myogenic potentials in patients with essential tremor

Although different neuroanatomical structures and pathways are emphasized as possible explanations for essential tremor (ET), there is still an ongoing debate. This study aimed to assess the role of brainstem and reflex pathways with cervical vestibular-evoked myogenic potentials (VEMP) in patients with ET. This prospective study included 34 patients with ET and 25 healthy controls. Cervical VEMP was performed in both groups and latencies, inter-peak latency intervals, peak-to-peak amplitudes and asymmetry ratios were recorded. There was statistically no significant difference between the groups in terms of age (38.9 ± 14.9 years vs. 38.9 ± 14.9 years, p = 0.673) and gender (female to male ratio: 14/11 vs. 20/14, p = 0.828). Right N1 latency and right N1–P1 interval were significantly longer in the patient group (p < 0.05). There was a significant positive correlation between the duration of disease and the right N1–P1 interval (p < 0.05). There was no significant difference between the patient and control groups in terms of bilateral P1 latency, left N1 latency, left N1–P1 interval, and bilateral N1 and P1 amplitudes (p˃0.05). Cervical VEMP may reveal the involvement of brainstem and associated reflex pathways in ET.     

LONG-TERM EFFECTS OF MILD EXERCISE ON INTRAOCULAR PRESSURE IN ATHLETES AND SEDENTARY SUBJECTS

The long-term effects of acute submaximal exercise on intraocular pressures (IOPs) of right-and left-eyes and recovery times to basement levels of IOP in postexercise periods in sedentary and physically fit subjects were investigated. Twenty-five sedentary and 24 physically fit subjects, ranging in age 17 to 22 years, participated. Intraocular pressures were measured by a pneumotonometer. Measurements were taken in the morning at about nine (at rest) and immediately, 30 min and 2 h after acute submaximal exercise. In sedentary subjects, IOPs of both right- and left-eyes decreased immediate after exercise, but, these decreases in both eyes continued 30 min and 2 h after exercise. In physically fit subjects, IOPs of both right- and left-eyes increased immediate after exercise, but decreased after 30 min exercise compared to basement levels, and this decrease continued 2 h after exercise. Acute submaximal exercise decreased IOPs of right and left eyes over a period 2 h in sedentary and physically fit subjects. IOP reducing after exercise was different between right- and left-eyes in sedentary subjects. These results suggest that exercise can be used in ocular hypertension treatment.     

Long-term effects of mild exercise on intraocular pressure in athletes and sedentary subjects

The long-term effects of acute submaximal exercise on intraocular pressures (IOPs) of right-and left-eyes and recovery times to basement levels of IOP in postexercise periods in sedentary and physically fit subjects were investigated. Twenty-five sedentary and 24 physically fit subjects, ranging in age 17 to 22 years, participated. Intraocular pressures were measured by a pneumotonometer. Measurements were taken in the morning at about nine (at rest) and immediately, 30 min and 2 h after acute submaximal exercise. In sedentary subjects, IOPs of both right- and left-eyes decreased immediate after exercise, but, these decreases in both eyes continued 30 min and 2 h after exercise. In physically fit subjects, IOPs of both right- and left-eyes increased immediate after exercise, but decreased after 30 min exercise compared to basement levels, and this decrease continued 2 h after exercise. Acute submaximal exercise decreased IOPs of right and left eyes over a period 2 h in sedentary and physically fit subjects. IOP reducing after exercise was different between right- and left-eyes in sedentary subjects. These results suggest that exercise can be used in ocular hypertension treatment.