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Biomedical subjects

S L Wolf

Publications and source records attributed to S L Wolf.

At least 19 recordsLinked to original sources
PubMed1979

Procedures for EMG biofeedback training in involved upper extremities of hemiplegic patients.

This article presents practical information about using electromyographic biofeedback to train specific muscle groups in the involved upper extermity of hemiplegic patients. Our approach is first to reduce hyperactivity in spastic musculature and then to increase activity levels in weak muscles. Electrode placements and a sequence of training procedures for muscles whose functions are most commonly impaired following stroke are described.

Arm↗
PubMed1979

Normative data on low back mobility and activity levels. Implications for neuromuscular reeducation.

Low back mobility and electromyographic movements were performed in 121 normal subjects, grouped by age and sex. Women tended to show greater ranges of motion for straight leg raising, trunk rotation and lateral bending while vertebral separation (forward flexion) was greater in men. A sex-age interaction was observed only in lateral bending, thus implying that for other mobility measurements, data within the age groupings employed in this study can be combined for men and women. Electromyographic data were integrated and quantified using EMG biofeedback equipment for unilateral or bilateral recordings made primarily from the erector spinae muscle between lumbar 3-4 and lumbar 4-5 levels, three centimeters lateral to the spinous processes. Dynamic (trunk flexion-extension, lateral rotation-standing, stooping) and static (quiet sitting, rotation-sitting) movements were performed over a ten second interval. Data analyses verified previous electromyographic studies by demonstrating the trunk extensor function of the erector spinae and the relatively greater unilateral activity when turning to the opposite direction in the erect posture. EMG silence was seen during full trunk flexion. Noticeable sex-age interaction were observed for all dynamic movements but not for static activities. Therefore, it is suggested that EMG data during dynamic movements in a normal population cannot be grouped for men and women within a specified age distribution. These data represent one series of baselines to which mobility and movement patterns in a back pain patient group can be compared. Suggestions are offered for the use of EMG biofeedback during dynamic lower back movements as a possible method of alleviating the pain state, perhaps by altering the patient's posture.

Adolescent↗
PubMed1979

Involuntary single motor unit discharges in spastic muscles during EMG biofeedback training.

The apparent involuntary single motor unit discharges observed in many extremity muscles of spastic patients necessitate monitoring raw electromyography during training sessions. The clinician should note that electronic components of some biofeedback instruments may amplify and distort these units so that the feedback, whether by meter or by variable pitch tone, may erroneously be perceived by the patient as a high level of muscle tension.

Action Potentials↗
PubMed1979

EMG biofeedback in stroke: effect of patient characteristics.

Forty-eight upper and 44 lower extremities of 52 stroke patients were treated using a clinical emg biofeedback training approach. The age, sex, hemiparetic side, duration of stroke or previous rehabilitation, and number of biofeedback training sessions had no significant relationship to treatment outcomes. Lower extremities responded more favorably to training than upper extremities, and the prospects for successful treatments in the upper limb were further diminished when proprioceptive impairments were present. Possible explanations for the poorer responsiveness of the upper extremity to emg biofeedback training are provided, the importance of a motivational element is stressed, and a suggestion is offered for the direction of future work designed to predict the value in applying this modality.

Adolescent↗
PubMed1978

Percutaneous recordings from peripheral nerves (preliminary communication).

The recently developed technique provides a precise assessment of neutral activity via intrafascicular axonal recordings from human peripheral nerves. With this technique it is possible to record from cutaneous afferent fibers. Receptive fields belonging to cutaneous afferents are readily perceived by patients due to orthodromic conduction of activity induced by mechanical activation of appropriate fibers. Temporal synchrony between peripherally applied stimuli and the proximally placed recording electrode assure continuity of the nerve. By sampling axonal activity from cutaneous fasciles at regular intervals following trauma of undefined etiology, a definite appraisal can be made concerning the integrity of a nerve and, hence, the need for surgical intervention. This is a preliminary report of the first such applications of this technique.

Adult↗
PubMed1978

Essential considerations in the use of EMG biofeedback.

In light of a developing, widespread interest in electromyographic biofeedback as both a clinical and research modality, this article reviews basic factors that the physical therapist must consider for successful biofeedback applications. These factors include the proper use and care of electrodes, correct grounding procedures, and appropriate feedback displays.

Biofeedback, Psychology↗
PubMed1978

Perspectives on central nervous system responsiveness to transcutaneous electrical nerve stimulation.

This review article is designed to further enlighten the physical therapist about pathways transmitting nociceptive information and about systems capable of inhibiting this transmission. At present, little information exists to explain how transcutaneous electrical nerve stimulation effects changes in pain perception. Contemporary knowledge regarding proposed modes of action for this modality is presented in light of current neurophysiological information. In explaining the action of transcutaneous electrical nerve stimulation, alternatives to the gate-control theory of pain are suggested as being quite possible. Questions regarding future investigations are proposed.

Brain Stem↗
PubMed1978

Relationship of selected clinical variables to current delivered during transcutaneous electrical nerve stimulation.

Nineteen normal subjects were given transcutaneous electrical nerve stimulation to the hypothenar eminence, back, or legs, using a selected constant-current device. Stimulation characteristics from this unit were measured. Stimulation, at 20- microsec or 80- microsec pulse widths, was provided at increasing strengths until subject tolerance or muscle contraction was reached. The current delivered at each stimulus setting for single or repeated intrasubject trials was reliable at each anatomical landmark. For intersubject single trials, current levels proved reliable in the hand and back but not at any of the three interelectrode distances evaluated in the leg. Possible explanations for this latter finding are offered. This study showed that, for those stimulation settings evaluated, at least one constant-current transcutaneous electrical nerve stimulation unit reliably delivers current of specific stimulus strengths to the hypothenar eminence or back.

Adolescent↗
PubMed1977

Objective determinations of sensibility in the upper extremity. Part I. Median nerve sensory conduction velocities.

Distal sensory conduction velocities were determined in 109 normal median nerves. A significant decrease in sensory conduction velocity was noted with increasing age. Latencies increased with age but this relationship was not significant in men. Variables which contribute to the wide range of normal conduction velocities are discussed, and the need for each clinician to establish his own testing procedure is stressed. An additional method for assessing sensory function is suggested.

Adult↗
PubMed1977

Objective determinations of sensibility in the upper extremity. Part II. Application of cutaneous stimuli in control subjects.

Sensitization statements were read to two groups of normal subjects to determine whether quantifiable thresholds for pressure, electrical, or tactile stimuli could be altered. Significant reductions in perception thresholds were observed for pressure and digital pulsed stimulation, but not for stimulation to the discomfort threshold, or two point discrimination. These data seem to suggest that increased sensitization is related to the ease of stimulus applications and the comparative simplicity of sensory processing.

Adult↗
PubMed1977

Objective determinations of sensibility in the upper extremity. Part III. Application of cutaneous stimuli in patients with peripheral nerve lesions.

Quantitative values for pressure, electrical, and two-point touch stimulation were examined in five patients with peripheral nerve injuries of the ulnar or median nerves. Analyses of profiles generated for each stimulus application in each patient participating in this preliminary study suggest that, following the reading of a sensitization statement, pressure and electrical shock threshold values are clearly reduced compared to similar measurements in the unaffected limb. Values obtained prior to the statement indicated progressively reduced thresholds, however. Changes in sensation appear to precede significant improvements in sensory nerve conduction velocity. Limitations in the sensory testing techniques as well as suggestions for improving its validity are discussed.

Adult↗
PubMed1977

Developing strategies for biofeedback. Applications in neurologically handicapped patients.

Strategies involving muscle biofeedback applications in the rehabilitation of neurologically handicapped patients are discussed. These include positioning of the limbs, initiating contractions, and controlling spasticity. Guidelines in the proper application of electrodes and biofeedback equipment are presented along with methods of documentation. The authors offer their training strategies as an initial guide and stress that uses of biofeedback need to be explored and documented.

Biofeedback, Psychology↗
PubMed1977

Sensory threshold measurements for electrical stimulation of the digits.

Repeated impedance measurements of electrical stimulation to the finger using the stimulator of an electromyograph were evaluated in seven normal subjects to determine whether reliable threshold values to perception of pain could be obtained. Stimuli were delivered through ring or disc electrodes separated by 3 cm and interfaced to the skin of the digit with EKG paste. Stimulation through these electrodes produced only relative values of threshold, expressed as a potentiometer dial setting. Such values proved to be meaningful only when repeated during a single session. A possible reason for the apparent unreliability of repeated measurements over time is discussed. When a constant current source was substituted, reliable and consistent threshold measurements were obtained. It is suggested that the clinician wishing to make accurate, repeatable and quantified measurements of patient thresholds to electrical stimulation of the finger employ a nonloading source, namely, a constant current or constant voltage stimulator.

Adult↗