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Biomedical subjects

D Halpern

Publications and source records attributed to D Halpern.

At least 37 records · Page 2Linked to original sources

Muscular hypertonia: quantitative analysis.

By a statistical method of analysis, the force applied to move a limb passively can be translated into physiologically relevant parameters relating to the muscle. The parameters identified and measured are the dynamic and static activity of the muscle and their interactions with the varying length of the muscle during stretch. This method of analysis has been shown to be of assistance in evaluating the reflex status of persons with central nervous system disorders in preparation for treatment and in measuring the effects of treatment.

Humans↗

Intramuscular neurolysis for spasticity in children.

Intramuscular neutrolysis with phenol has been used for 10 years in the management of spasticity in children. Best results depend on fastidious technique and realistic use of the procedure. Sedation or anesthesia was used in all cases -- 5% phenol in water was used for all procedures. The main indications were spasticity which interfered with function, either actual or potential, or with care. Where uninhibited vestibular or tonic neck reflexes affect muscle tone, or there is dystonia or athetosis, the procedure is less effective than where spasticity alone is present. Duration of relief of spasticity ranged from 1 month to more than 2 years. About one half of the lower extremity muscle treated required tenotomy later. Generally training was required after the procedure to obtain improved function. A representative sample of muscles treated, repeat procedures, and later surgery is discussed. The procedure is recommended for use in the management of spasticity in children as a way of improving function and/or care.

Adolescent↗

Electromyographic feedback and physical therapy for neuromuscular retraining in hemiplegia.

Electromyographic feedback was compared with physical therapy for its relative effectiveness in training motor activity in patients with hemiplegia. A cross over design was used, so that each patient served as his own control. Strong reinforcement for attentional direction and for successful response to established criteria was used with both modalities. Electromyography through auditory and visual display was found effective in improving electromyographic activity, but more limited in training effective function as measured by active range of motion. In some cases it was counterproductive. Using an instrumental modality permits attention to only a limited number of motor elements involved in a motion, and is even more limited with respect to the interplay of activation and inhibition of those components. The activity of physical therapy, using tactile, proprioceptive, visual and communicative modalities, has the capacity for attending and drawing attention to many motor elements, as well as to the complexities of activation of some components concomitantly with the inhibition of others during the training process. Electromyographic feedback was felt to be especially useful in its ability to enhance figure-background discrimination and bypass possible areas of sensory obtundation.

Aged↗

The training of coordination.

The training of coordination is generally considered a volitional activity, during which, by trial and perception of results, an individual selects the muscular activity resulting in the desired performance. This concept of volitionally directed complex coordination of multiple muscles with speed, skill, and strength does not stand the test of thorough evaluation. Attention is limited to 1 activity at a time, with the ability to shift attention not more frequently than 3 times per second. Only under special conditions can activity be limited to specific muscles during an untrained contraction without cocontraction of other muscles. However, with repeated practice of the desired activity, a pattern of performance is developed which can be carried out rapidly and forcefully without activation of other muscles. At that time, the consciousness is no longer directing the components of the activity but merely starting, maintaining, and stopping the performance. The development of these patterns, or engrams, by practice develops the capacity to automatically inhibit muscles that do not contribute to the performance of the desired pattern. The capacity for inhibition results in coordinated activation of the muscles contributing to the performance desired. Investigation of the development of coordination in many types of normal activities, as well as in neuromuscularly impaired patients, shows that engrams develop progressively by slow, precise practice of simple patterns, combined as they develop into more and more complex patterns, until the final skill is attained.

Attention↗

Histologic studies in animals after intramuscular neurolysis with phenol.

The histologic effects of the intramuscular injection of phenol concentrations ranging from 1% ot 7% were studied in rats and dogs at from one day to ten months after injection. The sites within the muscle localized by a standardized technique for electrical stimulation proved to be intramucular nerves, either near the terminal innervation band, or more proximally, mixed nerves running in the neurovascular bundle in the interfascicular regions of the muscle. The latter was by far the more frequent site of localization. The procedure is therefore identified as "intramuscular neurolysis" rather than motor end-plate or motor point block. Phenol causes nerve destruction with secondary denervation and atrophy, and muscle necrosis, Both nerve and muscle show regeneration which is well established by two months, and almost complete in three months.

Animals↗