The role of rigid and hinged polypropylene ankle-foot-orthoses in the management of cerebral palsy: a case study.

Ankle-foot orthoses are commonly used in the treatment of spastic cerebral palsy to hold the foot in a position conductive to a more functional gait. This study, utilizing quantitative biomechanical techniques, evaluates the effects of a rigid ankle-foot orthosis and a hinged ankle-foot orthosis on spastic cerebral palsy gait. The subject was a 4.5 year old female diagnosed as spastic diplegic cerebral palsied shortly after birth. Testing involved collection of kinematic coordinate data employing a WATSMART video system and ground reaction force data using a Kistler force plate. Jensen's (1978) photogrammetric method was used to estimate body segment inertial parameters. The hinged ankle-foot orthosis was found to be more effective than the rigid ankle-foot orthosis. The subject exhibited a more natural ankle motion during the stance phase of gait, greater symmetry of segmental lower extremity motion, and decreased knee moments during stance while wearing a hinged ankle-foot orthosis.

Fitts' reciprocal tapping task, a measure of motor capacity?

Employing Fitts' reciprocal tapping task, the capacity of the motor system in bits processed/second was assessed across different ages. In Exp. I a comparison was made among Grades 1, 5, 9, and university females. Motor capacity and average movement time/tap were significantly lower for Grade 1 girls than the other three grades. In addition, within-subject variability and percentage error rate decreased with increasing grade level. These findings were discussed in comparison to other studies looking at motor capacity changes across ages. Exp. II was designed to study the changes in motor capacity throughout 25 days of practice by two 5-yr.-old children. Two different methods were used to calculate motor capacity. One method (Kay, 1962) which assessed motor capacity separately for each tapping condition led to the conclusion that capacity increased with practice. A second method (Fitts & Peterson, 1964) treating all tapping conditions together in a regression equation and measuring capacity as the reciprocal of the slope (1/b) showed capacity to decrease with practice for one subject and oscillate with practice for the other subject. The general conclusion drawn from the two experiments was that motor capacity, as assessed by Fitts' tapping task, is not an extremely useful measure. Consideration of movement time is usually just as informative.

Dynamic properties of human motor units in the Hoffmann--reflex and M response.

The dynamic properties of motor units involved in unrestrained H-reflexes and M responses have been studied in seven normal adult males. A linear relationship was observed between the peak to peak EMG of the M response and its twitch tension. Linear relationships were also noted between the EMG and peak displacement, velocity, and acceleration of the evoked muscle twitch for both the H-reflex and the M response. Contraction times for motor units recruited in the H-reflex were longer than those for the M response at low levels of motor unit recruitment. For both responses, however, the contraction times (time to peak force) were markedly shorter than those reported for isometric conditions. Differences were also noted between the H-reflex and M response in the absolute values of the tension to EMG ratio. These differences, together with the longer contraction times for the H-reflex, are quite consistent with the view that different motor unit subpopulations are recruited in the early stages of the two responses. The results and their interpretation, in terms of differential motor unit recruitment, generally confirm the conclusions of studies in which isometric twitch contractions have been investigated.

Effects of H-reflex conditioning upon the contralateral alpha motoneuron pool.

H-reflex recovery curves have been elicited by subliminal conditioning stimuli applied to the ipsilateral and contralateral posterior tibial nerves in 10 healthy female subjects. In both types of recovery curve there was clear evidence of a period of facilitation in the ipsilateral soleus motoneuron pool 75-250 msec after the conditioning stimulus. These results indicate the bilateral nature of the facilitation and show it to be most probably produced by stimulus-evoked inputs as opposed to twitch-evoked inputs. If the facilitation is produced by descending long-loop reflex influences, then complementary evidence is provided for previous electromyographic data showing the bilaterality of long-loop reflexes evoked by percutaneous electrical stimulation. It is impossible, however, at the present time, to rule out the possible involvement of cutaneous afferent discharges or other stimulus evoked inputs in the late facilitation.

Cooperative stroke management project by a peer-review organization.

To improve the care of patients in Mississippi through increased adherence to nationally accepted ischemic stroke management guidelines, patterns for ischemic stroke services were determined from hospital chart review. Hospital-specific education and data feedback were performed to encourage international systems improvements. The Mississippi Foundation for Medical Care, Inc, reviewed records of Medicare beneficiaries discharged with the principal diagnosis of acute ischemic stroke from four hospitals over a 1-year period. Records were analyzed for compliance with stroke management guidelines. Hospital-specific and aggregate data were presented to the staffs of each hospital and the hospitals were encouraged to develop internal quality improvement projects. The Foundation reviewed 427 records of acute stroke patients, of whom 375 (87.8%) had ischemic stroke. Among the 427 stroke patients, there were 76 (17.8%) in-hospital deaths. Notable variances from the ischemic stroke management guidelines included those for emergent hypertension management, deep vein thrombosis prophylaxis, evaluation for cause of ischemic stroke, and use of antithrombotic therapy on discharge of ischemic stroke patients. Thus, the management of acute stroke patients in these four regional hospitals in Mississippi often differed from nationally accepted guidelines. We hope to improve the care of stroke patients by using the expertise of academic stroke physicians and hospital-specific analyses that are personally meaningful but not personally threatening to treating physicians.