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Biomedical subjects

J R Daube

Publications and source records attributed to J R Daube.

At least 73 records · Page 4Linked to original sources
PubMed1988

Prognostic value of electrodiagnosis in Guillain-Barré syndrome.

This study was designed to identify clinical and electrodiagnostic indicators of prognosis in Guillain-Barré syndrome (GBS). Sixty severe GBS patients (all bedfast, 22 ventilator dependent) were analyzed clinically and with standard electromyography and nerve conduction studies. Both ventilator dependence and rapid evolution of weakness were more common in patients with a poor prognosis. The most powerful predictor of a poor outcome was reduced mean compound muscle action potential amplitude (less than 10% of the lower limit of normal).

Action Potentials↗
PubMed1988

The utility of magnetic stimulation for routine peripheral nerve conduction studies.

The magnetic stimulator was compared with percutaneous electrical stimulation for activation of the median nerve at the wrist in four volunteers. Magnetic stimulation was unable to achieve supramaximal stimulation without activation of the ulnar nerve. The point of nerve depolarization could not be reliably estimated from the relationship of the stimulator head to the nerve. We conclude that the magnetic stimulator coil is as yet not suitable for routine electrodiagnostic use in the peripheral nervous system.

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PubMed1988

Deep branch ulnar neuropathy due to giant cell tumor: report of a case.

Electrophysiologic studies indicated a lesion of the deep branch of the ulnar nerve in the palm of a 42-year-old man with painless weakness and wasting of ulnar-innervated intrinsic hand muscles. Magnetic resonance imaging of this region demonstrated a soft-tissue mass in the palm distal to Guyon's canal. Surgical exploration disclosed a giant cell tumor of the tendon sheath, compressing the deep branch of the ulnar nerve.

Adult↗
PubMed1988

Peripheral neuropathic syndromes in giant cell (temporal) arteritis.

Of 166 consecutive patients with histologically confirmed giant cell (temporal) arteritis (GCA) seen during a 3-year period, 23 (14%) had clinically diagnosed peripheral neuropathic syndromes temporally coincident with clinically active GCA. Electromyography and nerve conduction studies were performed in 16, confirming abnormalities in all. Of the 23 patients, 11 had a generalized peripheral neuropathy, nine had multiple mononeuropathies, and three had a mononeuropathy. The nerves affected as mononeuropathies were the median, ulnar, peroneal, tibial, and sural nerves, and the C-5 and L-5 nerve roots. Angiography, performed in two patients, demonstrated widespread arteritis involving the lower limbs and, after 3 months of oral corticosteroid treatment in one of these patients, an amputation specimen showed chronic arteritis.

Aged↗
PubMed1988

Intraoperative monitoring of the facial nerve.

Anatomic preservation of the facial nerve, with maximal facial function, is one of the goals of acoustic neuroma surgery. Application of electrophysiologic monitoring techniques is useful in achieving this goal. Preoperative electromyography and nerve conduction studies provide important prognostic information for preservation of the nerve and postoperative function. Intraoperative electromyography alerts the surgeon to facial nerve proximity and potential injury. Direct nerve stimulation is utilized to confirm the location and integrity of the nerve. Matched-pair analysis of two groups of patients demonstrated an increased ability to preserve the facial nerve with less postoperative facial deformity.

Adolescent↗
PubMed1987

Electromyographic analysis of muscles across the elbow joint.

An electromyographic (EMG) technique was developed to study simultaneously the eight major elbow muscles in five normal subjects. Recordings of EMG activity in elbow muscles were obtained while the elbow joint was subjected to resisted flexion, extension, abduction, and adduction functions. The results indicate that activity in the major elbow muscles is determined by the size of the resultant flexion and extension moments created about the elbow joint, but not by varus and valgus moments. These results support the hypothesis that determination of muscle force about a joint depends on joint constraint, namely, the degree of freedom, the resultant joint forces and moments due to externally applied load, and also the function of the muscle, i.e., the line of action of the muscle that crosses the joint. The data may be used to further refine the calculation of muscle force distribution across the elbow joint.

Adolescent↗
PubMed1987

The value of ulnar somatosensory evoked potentials (SEPs) in cervical myelopathy.

In 57 patients with clinical signs and surgical documentation of compressive myelopathy, ulnar nerve somatosensory evoked potentials (SEPs) were more sensitive (with 74% abnormal) than either median or tibial nerve SEPs. The most frequent abnormalities were reduced or absent neck evoked responses and prolonged central conduction time. All subjects who had an SEP abnormality were identified by combined tibial and ulnar SEPs. Median nerve SEP added no additional information. Normal ulnar and tibial nerve SEPs were also able to exclude major cord damage in patients with cervical radiculopathy but little evidence of myelopathy.

Adult↗
PubMed1987

Improved preservation of facial nerve function with use of electrical monitoring during removal of acoustic neuromas.

Continuous spontaneous electromyographic activity and responses to electrical stimulation of the facial nerve in the surgical field were monitored in 48 patients undergoing primary removal of an acoustic neuroma. The operative and postoperative results in these patients were compared with the results in 48 patients who were matched for age and size of tumor and who underwent the same surgical procedure without intraoperative monitoring. Eighty-three percent of the patients had preoperative evidence of facial neuropathy, which was more severe with larger tumors. Postoperative facial nerve function was most accurately predicted on the basis of the extent of facial neuropathy on preoperative electrophysiologic testing. Anatomic preservation of the facial nerve in patients with large tumors was substantially improved in the monitored patients (67%) in comparison with those without monitoring (33%). No difference was noted in facial nerve function in the two groups of patients immediately postoperatively. By 3 months, the degree of improvement in the monitored group exceeded that in those who were not monitored, particularly in patients with medium-sized and large tumors.

Adult↗
PubMed1987

Monitoring of cortical evoked potentials during surgical procedures on the cervical spine.

We reviewed the results of intraoperative monitoring of short-latency cortical evoked potentials in 81 patients who underwent surgical procedures of the cervical spine. Of these patients, 43 had baseline somatosensory evoked potentials from stimulation of the upper and lower extremities, intraoperative monitoring for at least 3 hours, and absence of an intrinsic lesion of the spinal cord. Major reductions in amplitude of the ulnar and tibial cortical evoked potentials occurred shortly after induction of anesthesia in 12% of patients. Latencies gradually increased during the operation as the concentration of volatile anesthetic agents increased. In patients with preoperative evidence of cervical cord damage, the cortical responses showed more fluctuations and could be lost without major changes in the concentration of the anesthetic agent or surgical manipulation. In one patient, intraoperative monitoring of the cervical cord function prevented a postoperative neurologic deficit. Ulnar and tibial cortical evoked potentials were successfully monitored throughout operation in all patients in whom baseline scalp responses could be obtained, but careful monitoring of anesthetic effect is necessary for proper interpretation.

Adult↗
PubMed1987

Computer-assisted stereotactic ventralis lateralis thalamotomy with microelectrode recording control in patients with Parkinson's disease.

Stereotactic ventralis lateralis thalamotomy can be performed in selected patients with medically intractable parkinsonian tremor and rigidity. New technology, including computed tomography-based stereotaxis and microelectrode recording techniques, provides a data base for precise localization of thalamic lesions tailored to each patient and thus reduces the risk associated with such a procedure. At our institution, 12 patients with medically intractable parkinsonian tremor have undergone this procedure; all experienced alleviation or cessation of the tremor and no permanent disabling neurologic sequelae.

Adult↗
PubMed1987

Neuropathy in the Miller Fisher syndrome: clinical and electrophysiologic findings.

The clinical and electrophysiologic findings in 10 patients with Miller Fisher syndrome (ataxia, ophthalmoplegia, and areflexia) were reviewed. All patients had motor and sensory nerve conduction studies and EMG in the arm and the leg, and seven patients had cranial nerve conduction studies. Electrodiagnostic abnormalities were found in all patients and were characteristic of an axonal neuropathy or a neuronopathy with predominant sensory nerve changes in the limbs and motor damage in the cranial nerves. The pattern of abnormalities was distinct from the usual features seen in the major form of acute inflammatory polyneuropathy, the Guillain-Barré syndrome.

Action Potentials↗
PubMed1987

Recent applications of electrophysiologic monitoring during surgery.

A multiplicity of electrophysiologic monitoring methods are available to assist the surgeon in operating on a patient in whom there is a risk of damage to neural structures. The applications and problems of each method must be considered in selecting the monitoring technique for each individual patient.

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PubMed1986

The evaluation of suspected ulnar neuropathy at the elbow. Normal conduction study values.

Local compression of the ulnar nerve occurs at several points, with the elbow region being the most common. Nerve conduction studies can be useful in identifying and localizing such lesions; however, the specifics of the technique, including normal values, have not been firmly established. We evaluated the effect of elbow position on segmental conduction velocities (CVs), the influence of elbow, nerve segment length on CV calculations, the change in compound action potential amplitude at sites along the nerve, and the use of performing segmental sensory CVs. Conductions done with the elbow flexed produced less segment-to-segment CV variation than those obtained with the elbow extended. The influence of using overlapping nerve segments compared with short adjacent ones for segmental CV comparison is discussed.

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PubMed1986

Superficial peroneal nerve conduction studies for electromyographic diagnosis.

A new standardized surface technique for conduction studies of the superficial peroneal nerve was developed and applied to 35 normal subjects and 63 patients with peroneal mononeuropathies, lumbar radiculopathies, sciatic neuropathies, lumbosacral plexopathies, or peripheral neuropathies. The response amplitude was greater than 5 microV and the response peak latency was less than 4.1 msec in all normal subjects; however, 8.6% of normal subjects had at least one unelicitable superficial peroneal nerve response (6% of all limbs tested). These data were compared with those of previous studies. Although this technique did not improve the diagnosis of peroneal neuropathy, it did distinguish lumbosacral plexopathy and sciatic neuropathy from L5 radiculopathy and served as a second, easily approachable, sensory conduction study of the leg.

Action Potentials↗
PubMed1986

The exercise test in periodic paralysis.

Of 21 patients with clinically definite hypokalemic, hyperkalemic, or normokalemic periodic paralysis, 15 (71%) had a greater than normal increase in compound muscle action potential amplitude during 2-5 minutes of intermittent strong voluntary contraction of the muscle. This increase was followed by a progressive decline in amplitude, which was greater than in a control population and which was most rapid during the first 20 minutes after exercise. The amplitude often decreased to a level below the preexercise level. A similar response was seen in six of nine patients with periodic paralysis secondary to disorders such as thyrotoxicosis. This test may have value in the identification of patients with periodic paralysis.

Action Potentials↗
PubMed1986

Stationary waves recorded at the shoulder after median nerve stimulation.

A new recording method with a reference electrode on the stimulated arm defined two discrete far-field potentials just before the propagated near-field nerve action potential was recorded at Erb's point. Both potentials were stationary waves with the same latency at all recording sites. The first potential had the same onset and peak latencies as the propagated wave at the axilla; it corresponded to the first component of the P9 far-field potential recorded with scalp to noncephalic reference montages. The latency of the second potential coincided with that of the propagated wave entering the neck and corresponded to the peak of the P9 potential. The occurrence of these potentials where there are significant changes in the morphology of the volume conductor suggests that the P9 far-field potential is due to a change in the conducting medium that surrounds the nerve.

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PubMed1986

Electrophysiologic monitoring of facial nerve during temporal bone surgery.

Monitoring of peripheral nerves during surgical procedures decreases trauma to the nerve, which may preserve function. During 1984, electrophysiologic monitoring of the facial nerve was used during 32 operative procedures in and around the temporal bone. The largest group were for cerebellopontine angle tumors. Clinically, monitoring appeared to be helpful by providing objective evidence of trauma to the facial nerve and a method of demonstrating integrity of the nerve. However, review of this series did not reveal objective evidence of improved facial nerve preservation compared to results in a similar group of patients operated on without monitoring. We think that the monitoring is best done by personnel experienced with the technique.

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