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At least 397 records · Page 22Linked to original sources
PubMed1999

Intensity of leg and arm training after primary middle-cerebral-artery stroke: a randomised trial.

BACKGROUND: We investigated the effects of different intensities of arm and leg rehabilitation training on the functional recovery of activities of daily living (ADL), walking ability, and dexterity of the paretic arm, in a single-blind randomised controlled trial. METHODS: Within 14 days after stroke onset, 101 severely disabled patients with a primary middle-cerebral-artery stroke were randomly assigned to: a rehabilitation programme with emphasis on arm training; a rehabilitation programme with emphasis on leg training; or a control programme in which the arm and leg were immobilised with an inflatable pressure splint. Each treatment regimen was applied for 30 min, 5 days a week during the first 20 weeks after stroke. In addition, all patients underwent a basic rehabilitation programme. The main outcome measures were ability in ADL (Barthel index), walking ability (functional ambulation categories), and dexterity of the paretic arm (Action Research arm test) at 6, 12, 20, and 26 weeks. Analyses were by intention to treat. FINDINGS: At week 20, the leg-training group (n=31) had higher scores than the control group (n=37) for ADL ability (median 19 [IQR 16-20] vs 16 [10-19], p<0.05), walking ability (4 [3-5] vs 3 [1-4], p<0.05), and dexterity (2 [0-56] vs 0 [0-2], p<0.01). The arm-training group (n=33) differed significantly from the control group only in dexterity (9 [0-39] vs 0 [0-2], p<0.01). There were no significant differences in these endpoints at 20 weeks between the arm-training and leg-training groups. INTERPRETATION: Greater intensity of leg rehabilitation improves functional recovery and health-related functional status, whereas greater intensity of arm rehabilitation results in small improvements in dexterity, providing further evidence that exercise therapy primarily induces treatment effects on the abilities at which training is specifically aimed.

Activities of Daily Living↗
PubMed1986

Exercise-induced hypertension after repair of coarctation of the aorta: arm versus leg exercise.

The etiology of exercise-induced upper limb hypertension after repair of coarctation of the aorta is unknown. We hypothesized that blood flow across the coarctation repair site is a major determinant of such exercise-induced hypertension. Because arm ergometry should produce a smaller increase in descending aortic blood flow than treadmill exercise, we compared the changes in upper limb pressure and the coarctation gradient produced by each type of exercise at equivalent levels of heart rate and peak oxygen consumption in 28 children with repaired coarctation of the aorta. The children were classified into three groups: Group I, resting gradient less than 15 mm Hg and treadmill gradient less than 20 mm Hg; Group II, resting gradient less than 15 mm Hg and treadmill gradient greater than 20 mm Hg; and Group III, resting gradient greater than or equal to 15 mm Hg. Twelve children with no heart disease served as control subjects. All children were exercised to exhaustion with 45 minutes' rest between the two exercise protocols. There were no differences in maximal heart rate and oxygen consumption between the two types of exercise. In all groups, treadmill exercise produced a larger increase in arm systolic blood pressure and arm-leg gradient than did arm exercise. With treadmill exercise coarctation Groups II and III developed a greater rise in both arm-leg gradient and arm systolic pressure than was observed in the control subjects (p less than 0.05). However, with arm exercise, Group III developed a significantly greater rise in both arm pressure and arm-leg gradient (p less than 0.05) than was observed in the control subjects.

Adolescent↗
PubMed1996

Ankle blood pressure measurement, an acceptable alternative to arm measurements.

The use of automatic noninvasive blood pressure (NIBP) devices has become a common technique to monitor blood pressure intraoperatively. The usual cuff placement for these devices on the upper arm sometimes poses problems. As an alternative, many clinicians place the cuff on the ankle. This practice has not been previously investigated to determine its efficacy. The purpose of our study was to determine whether a noninvasive blood pressure cuff on the arm could be replaced by one on the ankle. We monitored 24 patients intraoperatively with two non-invasive blood pressure cuffs, one on the upper arm and one on the ankle. Systolic, diastolic, and mean pressures were obtained from each cuff placement at intervals of no shorter than 3 minutes. The time necessary to obtain the measurements and the presence of any artifact were also recorded. A total of 404 pairs of data were obtained and the systolic blood pressure ranged from 82 to 196 mm Hg. The mean and diastolic pressure readings were equivalent between the arm and ankle blood pressure readings. The systolic pressures were not equivalent, reflecting the fact that the ankle systolic blood pressure is physiologically higher than the arm systolic blood pressure. The difference between the times necessary to obtain the readings from arm or ankle was not statistically significant. Eight of the paired readings (2.0%) represented artifact, arbitrarily defined as a difference in mean blood pressure readings of 15 mm Hg between the arm and the ankle. Since the mean blood pressure readings obtained at the arm and at the ankle were statistically equivalent, we concluded that the ankle cuff placement provided a reliable alternative to the placement of the cuff on the arm.

Adult↗
PubMed2001

Comparison of transposed brachiobasilic fistulas to upper arm grafts and brachiocephalic fistulas.

BACKGROUND: Renewed interest in transposed brachiobasilic fistulas has occurred since the release of the National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) guidelines because it is an alternative method to achieve an upper arm fistula in patients who cannot achieve a functional brachiocephalic fistula. The objective of this study was to compare outcomes among transposed brachiobasilic fistulas, upper arm grafts, and brachiocephalic fistulas. METHODS: A cohort of patients with upper arm accesses was retrospectively identified. Access outcomes were determined from medical records and contact with physicians, dialysis providers, and patients. Primary outcome was thrombosis-free survival. Secondary outcomes were primary failure, time to use, risk of catheter-related bacteremia, need for intervention, incidence of access-related complications, cumulative, and functional patency. Group differences in age, sex, race, diabetes, peripheral vascular disease, and number of previous accesses were adjusted for in the analysis where appropriate. RESULTS: Transposed brachiobasilic fistulas, upper arm grafts, and brachiocephalic fistulas were compared in 59, 82, and 56 patients, respectively. Compared with transposed brachiobasilic fistulas, upper arm grafts were more likely to thrombose with an adjusted relative risk (RR) of 2.6 (95% CI, 1.3 to 5.3) excluding primary failures and 1.6 (95% CI, 1.0 to 2.7) when accounting for the lower risk of primary failure for grafts. Transposed brachiobasilic fistulas also required less intervention (0.7 vs. 2.4 per access-year, P < 0.01) and were less likely to become infected (0 vs. 13%, P < 0.05) than grafts. Mature brachiocephalic fistulas were less likely to fail (RR 0.3, 95% CI, 0.1 to 1.0) and showed a trend for less thrombosis (RR 0.3, 0.1 to 1.1) than mature brachiobasilic fistulas. There was no significant difference in cumulative patency (failure-free survival) among the three types of access if primary failure was included at the median follow-up of 594 days. Transposed brachiobasilic fistulas provided catheter-free access one month sooner than brachiocephalic fistulas and one month later than upper arm grafts. CONCLUSIONS: Transposed brachiobasilic fistulas provide cumulative patency equivalent to upper arm grafts and brachiocephalic fistulas. They are less likely to thrombose and become infected than upper arm grafts. Compared with brachiocephalic fistula, they are more likely to mature but are at increased risk of thrombosis after maturation. Transposed brachiobasilic fistulas should be considered before placing an upper arm graft for patients that cannot achieve a functional brachiocephalic fistula.

Arm↗
PubMed1986

Dyssynchronous breathing during arm but not leg exercise in patients with chronic airflow obstruction.

Some patients with chronic airflow obstruction experience dyspnea with mild arm exercise but not with more-intense leg exercise. To investigate why these patients have limited endurance during arm exertion, we studied ventilatory responses to exercise with unsupported arms in 12 patients with chronic airflow obstruction (mean [+/- SD] forced expiratory volume in one second, 0.68 +/- 0.28 liters). Unloaded leg cycling was also studied for comparison. In the five patients who had the most severe airflow obstruction, arm exercise was limited by dyspnea after 3.3 +/- 0.7 minutes, and dyssynchronous thoracoabdominal breathing developed. In the other seven patients, arm exercise was limited by the sensation of muscle fatigue after 6.1 +/- 2.0 minutes (P less than 0.05), and dyssynchronous breathing did not occur. None of the 12 patients had dyssynchronous breathing during unloaded leg cycling. Maximal transdiaphragmatic pressure, a measure of diaphragmatic fatigue, declined similarly after arm and leg exercise in both groups. During unsupported arm work, the accessory muscles of inspiration help position the torso and arms. We hypothesize that the extra demand placed on these muscles during arm exertion leads to early fatigue, an increased load on the diaphragm, and dyssynchronous thoracoabdominal inspirations. This sequence may contribute to dyspnea and limited endurance during upper-extremity exercise.

Adult↗
PubMed2005

Tissue tonometry before and after liposuction of arm lymphedema following breast cancer.

BACKGROUND: Arm lymphedema is a common complication after breast cancer treatment. Different conservative and surgical treatments have been used to reduce the arm swelling, but most have failed as chronic edema eventually transforms from a state of accumulated lymph fluid into increased deposition of subcutaneous fat, i.e. a non-pitting lymphedema. OBJECTIVE: To evaluate changes in tissue tonicity with an electronic tissue tonometer before and after liposuction. To validate the tonometer, outcome of surgery, and aspirate content. If tonometry can discriminate between "soft" and "hard" edema/swelling, it can be used to differentiate these types, as treatment differs. SUBJECTS AND METHODS: Twenty women with non-pitting unilateral postmastectomy arm lymphedema were operated on. The following measurements were performed: Tissue tonicity with a tonometer, its sensitivity on five different foam-polyethers by ten subjects, arm volumes, and adipose tissue aspirate content. RESULTS: Tissue tonicity values showed that the upper lymphedematous arm was harder than the normal one. After surgery it became softer, and at one year it was as soft as the normal arm. Polyether tonometries could clearly differentiate the various properties. A sample of three measurements was as good as ten. Horizontal vs. vertical measurements did not differ in the high-density polyethers. Complete reduction of the lymphedema was achieved. Adipose tissue content of the aspirate was 89%. CONCLUSION: The tonometer could register postoperative changes in tissue tonicity in the upper arm, but not in the forearm, which also showed significantly higher absolute values. Probably this is caused by the high adipose tissue content with little or no free fluid, thus resembling the normal arm in tonicity. Possibly also the thinner subcutaneous tissue in the forearm plays a role. Tonometry can differentiate if a lymphedematous arm that is softer or harder than the normal one. A harder swelling is dominated by adipose tissue and can be treated with liposuction, while the softer one is treated conservatively.

Adult↗
PubMed1999

The normal range for inter-arm differences in blood pressure.

OBJECTIVE: to establish the mean and normal range for the difference in simultaneous systolic and diastolic blood pressure measurements between the right and left arm. SUBJECTS: 462 subjects, age range 20-89 years, in sinus rhythm and with no history of stroke, 98 of whom had a history of cardiovascular disease or were taking vasoactive medication. METHODS: four simultaneous recordings of blood pressure in both arms were made using two automated sphygmomanometers with the subject supine after resting for 10 min. RESULTS: inter-arm systolic and diastolic blood pressure differences show a near normal distribution of values. Some individuals had clinically important differences in systolic and diastolic blood pressure between their arms. The magnitude of these differences was not related to the mean baseline blood pressure. Linear regression analysis did not demonstrate any significant relationship between inter-arm systolic or diastolic blood pressure difference and age in patients of either sex. For systolic blood pressure the mean difference between the right and left arm was 1.1 mmHg and the normal range was -9 mmHg to 11 mmHg. For diastolic blood pressure the mean difference was 0 mmHg and the normal range -10 mmHg to 10 mmHg. CONCLUSION: the frequency of significant inter-arm systolic and diastolic blood pressure differences suggests that the blood pressure should be taken in both arms at the initial consultation. At subsequent visits, the arm in which measurements are taken should be recorded in the case notes. The higher of the two readings should be used to guide further management decisions.

Adult↗
PubMed1989

Determinants of arm muscle and fat accretion during the first postnatal month in preterm newborn infants.

We measured arm muscle and fat areas in 22 preterm appropriate for gestational age infants at birth (mean +/- 1 SD birth weight: 1,640 +/- 484 g; gestational age: 31 +/- 2 weeks). Birth arm muscle and fat areas correlated significantly with gestational age (arm muscle: r = 0.86; p less than 0.001; arm fat: r = 0.75; p less than 0.001) and with birth weight. Deviations of birth weights from gestational age means (birth weight z-scores) were related more to variations in arm muscle area (r = 0.69; p less than 0.001) rather than arm fat area (r = 0.44; p = 0.04). Sixteen infants were followed over 4 weeks. They were most physiologically unstable (mean Physiologic Stability Index score = 5.3 +/- 3.5) during the first postnatal week when they also all lost weight. Their mean arm muscle area decreased significantly during the first week by greater than 10%, whereas the mean arm fat area remained unchanged. First week arm muscle losses were directly correlated with the lack of protein intake (r = 0.52; p less than 0.05). The regression equation predicted a protein intake of 4.06 g/kg/day (95% confidence interval: 2.3-6.4) to prevent first week muscle loss. Enteral intake and weight gain were established after week 1, accompanied by a significant reduction in physiologic instability (PSI score = 1.9 +/- 1.9; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMedDate not supplied

Responses to arm exercise in patients with compensated heart failure.

PURPOSE: This study compares the responses of 20 male patients (mean age 51 +/- 11 years) with stable heart failure during peak and submaximal arm and leg exercise. METHODS: On day 1, subjects completed two symptom-limited graded exercise tests, one with their arms and one with their legs. On day 2, subjects performed arm only and leg only exercise at a matched power output of 30 Watts (W). Ten age-matched healthy subjects served as controls. RESULTS: During peak arm exercise power output, oxygen consumption (VO2), ventilation, and rate-pressure product were higher in healthy subjects than in patients with heart failure. However, when a subject's peak VO2 or power output during arm exercise was expressed as a percentage of that achieved during peak leg exercise, no significant differences were noted between patients with heart failure and healthy subjects. Among both groups, rate-pressure product, VO2, ventilation, the ventilatory equivalent for O2, and respiratory exchange ratio were all higher when exercising at 30 W with the arms versus 30 W with the legs. Also, in patients with heart failure heart rate was higher (+6 min-1) and stroke volume index lower (-4 mL/m2) during submaximal arm than leg exercise. CONCLUSIONS: Although peak exercise capacity (Watts, VO2) during arm exercise is lower in patients with heart failure than healthy subjects, when expressed as a percentage of peak leg capacity, the extent of the exercise intolerance they experience during arm exercise does not differ from healthy subjects.

Adult↗
PubMed2003

The changing distribution of arm circumferences in NHANES III and NHANES 2000 and its impact on the utility of the 'standard adult' blood pressure cuff.

BACKGROUND: Accurate blood pressure measurement is dependent on using a blood pressure cuff that is appropriate to the patient's arm circumference. OBJECTIVE: This study identifies the change in distribution of arm circumferences in the United States and its impact on usage of the 'standard adult' cuff. METHOD: The most current National Health and Nutritional Examination Survey (NHANES) data, available on the website (http://www.cdc.gov/nchswww/nchshome.htm), covers NHANES III (Cycle 1, 1988-1991; 8381 subjects and Cycle 2, 1991-1994; 8566 subjects) and NHANES 2000 (1999-2000; 4,444 subjects). The weighted change in arm circumference between NHANES III as a whole and NHANES 2000 was calculated. Correlates for increased arm circumference were obtained via multivariate analysis. The predicted change in blood pressure cuff usage based on the changing prevalence of arm circumferences was calculated. RESULTS: The mean arm circumference for the whole population increased significantly from NHANES III to NHANES 2000 (31.83 +/- 0.08 cm versus 32.86 +/- 0.15 cm, p < 0.001) and in the hypertension population without reaching statistical significance (33.07 +/- 0.16 to 33.61 +/- 0.30 cm, p = 0.11). When adjusted regressions were performed, the increases in arm circumference were due to increasing weight in both the whole population and the hypertensives. The numbers of Americans predicted to require the 'standard adult' cuff to accurately measure blood pressure decreased from 76.2% to 66.3% while the number of Americans increased from 42.2% to 45%. CONCLUSIONS: The increasing prevalence of overweight and obese Americans found in NHANES III and NHANES 2000 has led to larger mean arm circumferences in hypertensives and the total population. This increased frequency of larger arm circumferences predicts that the 'large adult' cuff will be increasingly required in clinician's offices for accurate blood pressure measurement.

Adult↗
PubMed1988

Rate modulation by arm movements of the respiratory dependent rate responsive pacemaker.

The rate response to arm movements of the respiratory dependent rate responsive pacemaker (RDP3, Biotec) was assessed in four patients implanted with this pacemaker. The pacemaker was implanted in the left prepectoral region and the auxiliary impedance measuring electrode positioned subcutaneously over the right second intercostal space with its tip lateral to the mid-clavicular line. The lower rate of the pacemaker was programmed to 75 bpm. While holding the breath, swinging arm movements (30 times) resulted in rate acceleration. The peak rate was faster when the arm on the side of the auxiliary electrode was swung (mean +/- SEM, 117 +/- 8 compared to 130 +/- 5 bpm, P less than 0.5). The mean rate response of the subjects to brief treadmill exercise (Bruce stage I) performed with both hands holding the support rails, swinging the right arm only, swinging left arm only and swinging both arms were 108, 140, 135 and 128 bpm respectively. Impedance measurement confirmed the significant influence of arm movements on thoracic "impedance" changes, which was mainly caused by electrode motion artifacts affecting the two electrode measuring system. This effect was dependent on the relative positions of the impedance measuring electrodes (i.e., between the pacemaker casing the auxiliary lead). Subsequently the auxiliary lead of the respiratory pacemaker (MB-1, and Biorate) was implanted in the lower part of the chest on the right sternal edge in another patient. Rate acceleration was only observed when the arm on the side of the pacemaker was swung. As arm movements often accompany physical activities, pacing rate can be affected and should be considered when programming this pacemaker.

Arm↗
PubMed1996

Cutaneous vascular control in the arms of women with postmastectomy oedema.

The control of forearm skin blood flow was examined in the swollen arms of twelve women with oedema caused by breast cancer treatment. The swollen arm was compared with the opposite unaffected (control) arm. Using laser Doppler flux (LDF) and continuous finger blood pressure (BP) measurements, vascular control was tested by applying a range of provocations previously shown to alter cutaneous vascular resistance (CVR) in healthy subjects. The tests and the accepted mechanism were: post-ischaemic hyperaemia (locally mediated vasodilatation), inspiratory gasp and cool reflex (both sympathetically mediated vasoconstriction), arm dependency (locally mediated vasoconstriction), and core heat load (sympathetically mediated vasodilatation). CVR was calculated as BP/(LDF-biological zero). Three differences between the control and swollen arms were identified. (i) The laser Doppler biological zero signal was significantly higher on the swollen side (P = 0.005, Student's paired t test). (ii) Baseline LDF was significantly lower on the swollen side (P = 0.002), and apparent CVR correspondingly higher. (iii) Cumulative reactive hyperaemia (area under the LDF curve above baseline) was significantly less on the swollen side (P = 0.03), although peak flux was not significantly different. Inspiratory gasp, cool reflex, arm dependency and core heat load produced changes of similar magnitude in both arms. It appears that sympathetic neural control and local vasoconstrictor control in arm dependency are normal in arm lymphoedema but that locally mediated vasodilator control is impaired. In addition, baseline skin blood flow may be reduced in this condition. The results provide no support for impairment of vascular tone as a contributory factor to the oedematous state.

Aged↗
PubMed2002

Sequential control signals determine arm and trunk contributions to hand transport during reaching in humans.

When reaching towards objects placed outside the arm workspace, the trunk assumes an active role in transport of the hand by contributing to the extent of movement while simultaneously maintaining the direction of reach. We investigated the spatial-temporal aspects of the integration of the trunk motion into reaching. Specifically, we tested the hypothesis that the efficiency ('gain') of the arm-trunk co-ordination determining the contribution of the trunk to the extent of hand movement may vary substantially with the phase of reaching. Sitting subjects made fast pointing movements towards ipsi- and a contralateral targets placed beyond the reach of the right arm so that a forward trunk motion was required to assist in transporting the hand to the target. Sight of the arm and target was blocked before the movement onset. In randomly selected trials, the trunk motion was unexpectedly prevented by an electromagnet. Subjects were instructed to make stereotypical movements whether or not the trunk was arrested. In non-perturbed trials, most subjects began to move the hand and trunk simultaneously. In trunk-blocked trials, it was impossible for the hand to cover the whole pointing distance but the hand trajectory and velocity profile initially matched those from the trials in which the trunk motion was free, approximately until the hand reached its peak velocity. The arm inter-joint co-ordination substantially changed in response to the trunk arrest at a minimal latency of 40 ms after the perturbation onset. The results suggest that when the trunk was free, the influence of the trunk motion on the hand trajectory and velocity profile was initially neutralized by appropriate changes in the arm joint angles. Only after the hand had reached its peak velocity did the trunk contribute to the extent of pointing. Previous studies suggested that the central commands underlying the transport component of arm movements are completed when the hand reaches peak velocity. These studies, together with the present finding that the trunk only begins to contribute to the hand displacement at peak hand velocity, imply that the central commands that determine the contributions of the arm and the trunk to the transport of the hand are generated sequentially, even though the arm and trunk move in parallel.

Adult↗
PubMed1995

The functional significance of arm movements in neonates.

Arm movements made by newborn babies are usually dismissed as unintentional, purposeless, or reflexive. Spontaneous arm-waving movements were recorded while newborns lay supine facing to one side. They were allowed to see only the arm they were facing, only the opposite arm on a video monitor, or neither arm. Small forces pulled on their wrists in the direction of the toes. The babies opposed the perturbing force so as to keep an arm up and moving normally, but only when they could see the arm, either directly or on the video monitor. The findings indicate that newborns can purposely control their arm movements in the face of external forces and that development of visual control of arm movement is underway soon after birth.

Arm↗
PubMed1988

Arm fat and muscle areas in infancy.

Growth of arm muscle, fat and water areas were evaluated longitudinally in a prospective study in 81 infants from birth to the age of 12 months. The percentage of arm fat area v the cross sectional upper arm area increased at the age of 15 days with a peak peak at the age of 6 months while arm muscle area increased progressively throughout the year. As arm water area represented only 1% of cross sectional upper arm area, calculations of arm fat and muscle areas can be carried out from measurements of mid arm circumference and tricipital skinfold at 15 seconds. Percentiles are presented for the upper arm fat and muscle areas, which can be used as index for the infants' nutritional state.

Adipose Tissue↗
PubMed1975

Maximal oxygen consumption test during arm exercise--reliability and validity.

The reliability and validity of a continuous progressive arm test, in which maximal 02 consumption (V02 max arm) is determined, were analyzed. Forty-one men (28.2 +/- 8.8 yr) performed the test twice. Eighteen additional men (22.6 +/- 5.6 yr) performed the arm test, as well as the treadmill run, in which maximal O2 consumption VO2max leg) was determined. The validity of the VO2 max arm test was computed, using VO2 max leg as a criterion for the individual's aerobic capacity. The reliability coefficients of VO2 max arm, VEmax arm, and HRmax arm were 0.94, 0.98, and 0.76, respectively, indicating a high reliability of the testmthe validity coefficient of VO2max arm was only 0.74. The regression equation of VO2max leg on VO2max arm was y = 24.4 + 0.9 +/- 4.4 (Syx). These findings indicate that, following the suggested protocol, the individual repeatedly uses the same muscles and does reach an all-out stage. However, different individuals apparently are aided by their trunk and leg muscles to different degrees, which lowers the validity of this test as a predictor of aerobic capacity.

Adult↗
PubMed2003

Effect of rhythmic arm movement on reflexes in the legs: modulation of soleus H-reflexes and somatosensory conditioning.

During locomotor tasks such as walking, running, and swimming, the arms move rhythmically with the legs. It has been suggested that connections between the cervical and lumbosacral spinal cord may mediate some of this interlimb coordination. However, it is unclear how these interlimb pathways modulate reflex excitability during movement. We hypothesized that rhythmic arm movement would alter the gain of reflex pathways in the stationary leg. Soleus H-reflexes recorded during arm cycling were compared with those recorded at similar positions with the arms stationary. Nerve stimulation was delivered with the right arm at approximately 70 degrees shoulder flexion or 10 degrees shoulder extension. H-reflexes were evoked alone (unconditioned) or with sural or common peroneal nerve (CP) conditioning to decrease or increase soleus IA presynaptic inhibition, respectively. Both conditioning stimuli were also delivered with no H-reflex stimulation. H-reflex amplitudes were compared at similar M-wave amplitudes and activation levels of the soleus. Arm cycling significantly reduced (P < 0.05) unconditioned soleus H-reflexes at shoulder flexion by 21.7% and at shoulder extension by 8.8% compared with static controls. The results demonstrate a task-dependent modulation of soleus H-reflexes between arm cycling and stationary trials. Sural nerve stimulation facilitated H-reflexes at shoulder extension but not at shoulder flexion during static and cycling trials. CP nerve stimulation significantly reduced H-reflex amplitude in all conditions. Reflexes in soleus when sural and CP nerve stimulation were delivered alone, were not different between cycling and static trials; thus the task-dependent change in H reflex amplitude was not due to changes in motoneuron excitability. Therefore modulation occurred at a pre-motoneuronal level, probably by presynaptic inhibition of the IA afferent volley. Results indicate that neural networks coupling the cervical and lumbosacral spinal cord in humans are activated during rhythmic arm movement. It is proposed that activation of these networks may assist in reflex linkages between the arms and legs during locomotor tasks.

Adult↗
PubMed2002

Distribution of eye- and arm-movement-related neuronal activity in the SEF and in the SMA and Pre-SMA of monkeys.

We analyzed neuronal activity in the supplementary eye field (SEF), supplementary motor area (SMA), and presupplementary motor area (pre-SMA) during the performance of three motor tasks: capturing a visual target with a saccade, reaching one arm to a target while gazing at a visual fixation point, or capturing a target with a saccade and arm-reach together. Our data demonstrated that each area was involved in controlling the arm and eye movements in a different manner. Saccade-related neurons were found mainly in the SEF. In contrast, arm-movement-related neurons were found primarily in the SMA and pre-SMA. In addition, we found that the activity of both arm-movement- and saccade-related neurons differed depending on the presence or absence of an accompanying saccade or arm movement. Such context dependency was found in all three areas. We also discovered that activity preceding eye or arm movement alone, and eye and arm movement combined, appeared more often in the pre-SMA and SEF, suggesting their involvement in effector-independent aspects of motor behavior. Subsequent analysis revealed that the laterality of arm representation differed in the three areas: it was predominantly contralateral in the SMA but largely bilateral in the pre-SMA and SEF.

Animals↗