Postural sway of the affected and nonaffected pelvis and leg in stance of hemiparetic patients.

OBJECTIVES: To study potential differences between sway of the paretic and of the nonparetic pelvis and leg in standing hemiparetic patients by comparing measurements of corresponding bilateral waist and leg sites, and by comparing the results to those of healthy control subjects. DESIGN AND SETTING: Anterior-posterior and mediolateral sway of 15 hemiparetic patients and 13 healthy control subjects was measured with the eyes open and closed during quiet stance. Data were collected via an ultrasonic-based system that continuously monitored the position of four transducers mounted bilaterally on the anterior aspect of the pelvis and on each tibial tuberosity. Sway of each transducer marker was calculated by the standard deviation around its mean position and by its mean speed. Descriptive statistics, analysis of variance, and cross-correlation analysis were used for comparing hemiparetic patients with healthy subjects, as well as for determining the effects of body level, body side, and vision on postural sway. RESULTS: For all four measurement sites and in both the anterior-posterior and mediolateral axes, the hemiparetic patients had larger sways than the control subjects. Patients' sway on the paretic side was larger than on the nonparetic side, whereas no side differences were detected in the control subjects. For both groups, waist sway was larger than legs' sway. Cross-correlation values between sway of the ipsilateral waist and leg on each body side, as well as between the two legs, were substantially lower in the patients than in healthy subjects. CONCLUSIONS: Postural sway of standing hemiparetic patients is characterized by an asymmetrical profile that is expressed both in larger sway values of the paretic than of the nonparetic side, and in low temporal synchronization between sway of the legs and of the pelvis as well as between the two legs. Impairment in the ability to stabilize the distal segments of the lower extremity on the paretic side, rather than in stabilization of the pelvis, appears to underlie the enhanced postural sway of hemiparetic patients during stance.

Repetitive practice of a single joint movement for enhancing elbow function in hemiparetic patients.

The primary goal of this study was to assess whether repetitive practice of flexion-extension movements of the affected elbow in hemiparetic patients enhances performance and to compare the effects of this practice mode to the effects of the physical therapy variable exercise program which is routinely applied during sessions. Subjects were 27 poststroke hemiparetic patients, residents of a rehabilitation institute, divided into an experimental (n = 15) and a control group (n = 12). The former were treated with 800 repeated elbow movements in a maximal predetermined amplitude of 80 degrees, provided in 8 equal sessions every other day. The latter received 10 min. of conventional physical therapy for the paretic upper extremity at similar time intervals. Pre- and posttreatment assessments included the bilateral measurements of kinematic variables and activation latencies of the biceps and triceps brachi muscles as well as motor and functional tests. For all criterion variables, the findings pointed to comparable improvement in both groups. It was concluded that repetitive elbow movements had no unique training effect on the kinematics of movement and on activation latencies of the primary muscles controlling elbow function in hemiparetic patients. Further, transfer of the effects of training to execution of movements towards and from the mouth was also comparable in both groups, pointing again to there being no particular advantage in using repetitive movements as a training mode for enhancement of elbow function in hemiparetic patients.

Somatosensory evoked potentials of the posterior tibial nerve in hemiparetic patients: relation to stance balance and walking ability.

OBJECTIVES: To examine the association between stance ability and walking performance of poststroke hemiplegic patients and their posterior tibial nerve somatosensory evoked potentials (SEPs). DESIGN AND SETTING: Fifteen patients, residents of a geriatric rehabilitation hospital, were evaluated twice, with a 2-week interval between sessions. In each session, clinical tests of stance balance and walking ability were performed, and bilateral SEPs to stimulation of the posterior tibial nerve were recorded. Eight healthy, age-matched control subjects underwent the same tests in a single session, but SEPs were recorded unilaterally. Correlation analysis and analysis of variance (ANOVA) were used for studying the prognostic value of the initial posterior tibial nerve SEP measurements as well as the within- and between-sessions relationships between the clinical-functional tests and the SEP data. RESULTS: No significant correlations between the initial SEP values and functional improvement were established. Within each session, positive significant correlations existed between decreased latencies of several of the medium-latency SEP waves and the performance of stance and gait tasks. However, the between-sessions improvement in stance balance was not correlated with a decrease in latency of the SEP peaks or with an increase in their amplitudes. As to walking ability, in those patients whose gait significantly improved, a significant shortening of P37 and P54 latencies took place. CONCLUSIONS: The association between the initial and/or the 2-week changes in SEP of the posterior tibial nerve and improvement in stance and walking abilities is equivocal. In addition, the applicability of SEP measurements is limited by patients' physical status and cooperation. The clinical significance of posterior tibial nerve SEP testing in poststroke hemiparetic patients is therefore debatable.

Electromyographic and positional changes in the elbows of spastic hemiparetic patients during walking.

The displacement of the paretic elbow of hemiparetic patients into flexion during walking is an acknowledged associated reaction characteristic of upper limb spasticity. The main purpose of this study was to examine the step-dependent pattern and magnitude of the angular and electromyographic changes which take place during this flexion movement. Steps-related changes in elbow angle were measured on the paretic side of 14 hemiparetic patients during walking with a 4-point cane. The EMG activity of the ipsilateral biceps and triceps brachii muscles was concomitantly recorded. The activity of the brachioradialis muscle in 8 patients was monitored as well. In another trial, the angular and electromyographic activities were measured bilaterally in 7 patients during free walking. Flexion movement on the paretic side was characterized by a steep increase in flexion occurring during the first 4 steps, followed by a more gradual rise with successive stepping. Neither the electromyographic activity of the elbow flexor nor that of the extensor muscles was related to that flexion movement. The excursion into flexion on the non-paretic side was smaller than on the paretic side and incorporated flexion-extension fluctuations. The associated reaction at the paretic elbow during walking is a postural response which is triggered by the balance perturbation in the gait activity. It starts with a steep rise in flexion which seems to be reflexive in nature. The preservation of elbow flexion during walking may be an expression of stiffening of the elbow flexor muscles fibers.

Somatosensory evoked potentials in aphasic patients.

The purpose of this study was to employ evoked potentials to evaluate the function of the somatosensory system in a group of right hemiplegic aphasic patients in whom conventional physical examination was inapplicable. Bilateral somatosensory evoked potentials (SEPs) in response to stimulation of the median nerve were recorded in 20 patients, and unilateral recordings were performed with 20 healthy, aged, matched controls. The major abnormality, present in 13 patients, was absence or reduction of the amplitude of the cortical components N19 and P22 in the lesioned side of the brain. Consequently, the only significant difference between the lesioned versus nonlesioned brain side in patients, and between patients and control subjects was in the amplitude of the cortical components. Since a strong correlation exists between the detected abnormality and impaired somatosensory function, it is concluded that it is highly probable that many aphasic patients suffer somatosensory deficits which, being difficult to assess, are overlooked by the medical personnel.

An ultrasonic-operated kinematic measurement system for assessment of stance balance in the clinic.

This study describes the application of a kinematic measurement system based on ultrasonic technology to enable the assessment of stance balance in the clinic. The system is composed of 1-8 ultrasonic transducer markers which transmit ultrasonic waves, and three ultrasonic receivers. The spatial position of each marker is monitored by calculation of the time interval between transmission and reception of the wave. Sway data from the waist of 44 healthy subjects and 15 hemiparetic patients were collected during quiet stance. The results distinguished between data collected with and without vision, between patients and controls, and between the two sides of the body. The findings were found to be valid and reliable in repeated measurements. RELEVANCE:--Assessment of stance balance in the clinic is a requisite for quantifying disability and measuring improvement in patients with postural control deficits. Due to high costs and complexity of operation, the use of prevailing equipment for these purposes is mainly confined to research facilities. This paper describes a unique kinematic measurement system whose low price and ease of operation make it feasible for clinical use.

Electromyographic activity of the biceps brachii muscles and elbow flexion during associated reactions in hemiparetic patients.

Activity of the biceps brachii muscles and movements of the elbows were studied during associated reactions in hemiparetic patients and in healthy volunteers. Onset time and increase in electromyographic (EMG) activity during associated reactions and onset of elbow flexion and its maximal magnitude were measured. Testing was performed while standing with a footswitch attached to the sole of the nonparetic foot in patients and to the sole of the right foot in controls. Lifting of that foot generated a trigger signal that served to time the dependent variables. Bilateral EMG activity associated with one foot stance appeared in the two upper extremities in both patients and controls. Elbow flexion occurred in the majority of patients bilaterally, whereas in controls it frequently took place on one side only. There was a significant difference between patients and controls in onset of EMG activity and elbow flexion. This difference indicates an earlier preparatory activity to one foot stance in the upper limbs of patients than in healthy controls. The greatest excursion into flexion was measured in the paretic upper extremity of patients; it significantly exceeded both the flexion angle measured in controls and increase in flexion angle on the nonparetic side. Further understanding of the nature of associated reactions seems to be required for their adequate treatment by physical procedures.