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Biomedical subjects

G Felsenthal

Publications and source records attributed to G Felsenthal.

At least 37 records · Page 2Linked to original sources
PubMed1984

Handcuff neuropathy: two unusual cases.

Handcuff applications may result in compression of peripheral nerves at the wrist, and most reported cases involve only the superficial radial nerve. In this report, two cases of bilateral handcuff neuropathy involving multiple nerves were confirmed by electrodiagnostic findings of membrane instability, prolonged latencies and/or conduction block. In addition to the superficial radial nerves, one case involved the median nerves, and a second case the ulnar nerves. It was postulated that injury might occur to any nerve at the wrist as a result of pressure and edema from handcuffs, with the radial nerve most frequently involved due to its superficial location. Radial nerve injury has been described as functionally insignificant; however for the two cases presented, in which the median or ulnar nerves were involved, significant disability resulted, and a rehabilitation program was indicated.

Adult↗
PubMed1984

The physiatrist as primary physician for patients on an inpatient rehabilitation unit.

Eighty-two patients admitted to a predominantly geriatric inpatient rehabilitation unit were followed throughout their stay in order to document their need for medical management. Their average age was 74.1 years and mean length of stay was 27.9 days. A total of 302 indications for medical intervention (3.7/patient) were found. In addition there were 2.8 medication changes/patient found when comparing admission to discharge medications, and 0.7 medications/patient prescribed for intercurrent illnesses. Actual documented loss of planned therapy time was found 21 times, involving 19 patients but exceeded 1 day in only six patients. Fifty-eight patients were ultimately discharged home, 14 were discharged to nursing homes (7 for social reasons), and 10 were transferred to an acute general hospital. Adverse drug reactions occurred in 27% of the patients and incidence rate paralleled the number of medications prescribed for the patient. This study indicates that the physiatrist on an inpatient rehabilitation unit must function as team manager or program director, and as the patient's primary physician. By managing medical problems effectively, the physician limits the loss of therapy time, thus shortening the length of stay and enabling the patient to continue to participate in his rehabilitation program.

Aged↗
PubMed1983

Changes in duration and amplitude of the evoked muscle action potential (EMAP) over distance in peroneal, median, and ulnar nerves.

Standard nerve conduction techniques measure the conduction of the fastest conducting axons. Slower conducting axons determine the amplitude, duration, and configuration of the EMAP. Normal data showing the change in amplitude and duration of the evoked EMAP over a length of nerve segment as well as the change per centimeter of that nerve segment has been lacking. This study supplies this data for the peroneal, median and ulnar nerves (tables 2-5) and gives examples of clinical application of these techniques in the diagnosis of compression syndrome and peripheral neuropathies with demyelination. Emphasis is also placed on potential sources of error which may affect the results obtained using these techniques. Further study of the application of these techniques in the diagnosis of neuropathies is indicated.

Action Potentials↗
PubMed1982

Asymmetric hamstring reflexes indicative of L5 radicular lesions.

There is no commonly accepted reflex from L5 innervated muscles. Hamstring muscles are primarily innervated by the L5 and S1 roots. It is shown that in the presence of symmetrically active gastrocsoleus reflexes, asymmetry of the hamstring reflexes indicates an L5 root lesion. We describe a method for eliciting the medial hamstring reflex by percussing the conjoint tendon of the semitendinosus and biceps femoris muscles at the level of the ischial tuberosity. Electromyographic, myelographic, and operative data confirmed the presence of an L5 root lesion in 7 patients with asymmetric hamstring reflexes.

Back Pain↗
PubMed1979

Palmar conduction time of median and ulnar nerves of normal subjects and patients with carpal tunnel syndrome.

The wrist-palm conduction time for the median and ulnar nerves was determined using antidromic technique in thirty normal subjects. For the median nerve, the conduction time was 1.6 msec. to initial deflection from baseline and 1.7 msec. to peak of the initial negative deflection for the mean plus 2 SD. The median wrist-palm conduction time was then compared to the difference between the median and ulnar wrist-digit conduction times (mean plus 2 SD of 0.5 msec. measured either to initial deflection or peak negative deflection) in order to determine which technique aids more in the electrodiagnosis of patients with a presumptive clinical diagnosis of carpal tunnel syndrome but which normal distal sensory latencies. It was found in ten patients that the results of these two electrodiagnostic methods paralleled each other, and neither appeared more sensitive than the other in establishing the diagnosis.

Adult↗
PubMed1978

Sensory conduction in the musculocutaneous nerve.

This report describes an antidromic technique for studying conduction in the sensory branch of the musculocutaneous nerve, the lateral cutaneous nerve of the forearm. Surface stimulation was done at the elbow where the nerve becomes superficial, and surface recordings were made 12 cm distally over the course of the nerve. Sixty nerves in 30 normal persons were examined. The mean latency to onset of the action potential was 1.8 +/- 0.1 msec with a mean conduction velocity of 65 +/- 3.6 meters/sec. Mean amplitude of the action potential was 24 +/- 7.2 muv.

Action Potentials↗
PubMed1978

Median and ulnar muscle and sensory evoked potentials.

The medical literature was reviewed to find suggested clinical applications of the study of the amplitude of evoked muscle action potentials (MAP) and sensory action potentials (SAP). In addition, the literature was reviewed to ascertain the normal amplitude and duration of the evoked MAP and SAP as well as the factors affecting the amplitude: age, sex, temperature, ischemia. The present study determined the normal amplitude and duration of the median and ulnar MAP and SAP in fifty normal subjects. The amplitude of evoked muscle or sensory action potentials depends on multiple factors. Increased skin resistance, capacitance, and impedance at the surface of the recording electrode diminishes the amplitude. Similarly, increased distance from the source of the action potential diminishes its amplitude. Increased interelectrode distance increases the amplitude of the bipolarly recorded sensory action potential until a certain interelectrode distance is exceeded and the diphasic response becomes tri- or tetraphasic. Artifact or poor technique may reduce the potential difference between the recording electrodes or obscure the late positive phase of the action potential and thus diminish the peak to peak amplitude measurement. Intraindividual comparison indicated a marked difference of amplitude in opposite hands. The range of the MAP of the abductor pollicis brevis in one hand was 40.0--100% of the response in the opposite hand. For the abductor digiti minimi, the MAP was 58.5--100% of the response of the opposite hand. The median and ulnar SAP was between 50--100% of the opposite SAP. Consequent to these findings the effect of hand dominance on the amplitude of median and ulnar evoked muscle and sensory action potentials was studied in 41 right handed volunteers. The amplitudes of the median muscle action potential (p less than 0.02) and the median and ulnar sensory action potentials (p less than 0.001) were significantly less in the dominant hand. There was no significant difference between the ulnar muscle action potentials or for the median and ulnar distal motor and sensory latencies in the right and left hands of this group of volunteers.

Action Potentials↗
PubMed1978

Comparison of evoked potentials in the same hand in normal subjects and in patients with carpal tunnel syndrome.

The amplitude of the evoked median and ulnar sensory action potential (SAP) was measured in fifty normal volunteers (4) and median and ulnar SAP in opposite hands were compared. In addition, the amplitude of the median response was compared to the ulnar response. It was found that the lower limit of the range of observations for the median amplitude was 20 muV, the range of observations for the median/median SAP ratio was 50--100%, and that in only 3 observations out of 100 normal hands was the median/ulnar SAP ratio less than 80%. In a series of 60 patients with carpal tunnel syndrome (CTS), 22 had bilateral involvement. The median SAP was obtainable in 62 of these diagnosed cases of CTS. Forty of these 62 cases could be identified by one of the three amplitude criteria: median SAP of less than 20 muV; median/median amplitude percentage of less than 50%; or a median/ulnar amplitude of less than 80%.

Action Potentials↗