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Biomedical subjects

D L Menkes

Publications and source records attributed to D L Menkes.

12 recordsLinked to original sources

Slow-frequency repetitive transcranial magnetic stimulation in a patient with focal cortical dysplasia.

PURPOSE: To evaluate the effect of slow-frequency repetitive transcranial magnetic stimulation (SF-rTMS) on interictal epileptiform activity and seizure frequency in a patient with medically refractory partial seizures due to focal cortical dysplasia. METHODS: A 9-cm circular coil was positioned over the area of cortical dysplasia. One hundred stimuli given at 0.5 Hz at 5% below motor threshold were given biweekly for four consecutive weeks. The EEG was recorded for 30 min before and after the first 100 stimuli. The number of seizures during the month of stimulation was compared with that of the month before stimulation. RESULTS: Stimulation was associated with a 70% reduction in the frequency of seizures and a 77% reduction in the frequency of interictal spikes. No seizures occurred during stimulation. CONCLUSIONS: SF-rTMS was safe and well tolerated in this patient. The reduction in seizures and interictal spikes associated with SF-rTMS supports the concept of SF-rTMS-induced cortical inhibition.

Adult↗

Current perception threshold: an adjunctive test for detection of acquired demyelinating polyneuropathies.

Current Perception Threshold (CPT) evaluation quantifies the sensory threshold to transcutaneous electrical stimulation of three sensory fiber subtypes: A-beta (2,000 Hz), A-delta (250 Hz) and C fibers (5 Hz). Demyelinating polyneuropathies tend to affect larger myelinated fibers before smaller unmyelinated fibers, and they usually begin at the proximal nerve roots or terminal axons, due to relative weakness of the blood-nerve barrier in these locations. Axonal polyneuropathies tend to affect smaller fibers before larger fibers, in a distal to proximal gradient. Ten patients with demyelinating polyneuropathy and ten patients with axonal polyneuropathy underwent CPT testing. CPT comparisons were made with regard to side-to-side asymmetries, fiber type involvement, and the ratio of fiber types involved. The C2, lateral antebrachial cutaneous, and sural distributions were examined bilaterally. Demyelinating polyneuropathies were detected with 50% sensitivity and 100% specificity. This diagnostic sensitivity is similar to that of published criteria based upon motor nerve conduction. CPT testing can distinguish demyelinating from axonal polyneuropathies. It may be particularly helpful in patients with predominantly sensory symptoms in whom EMG/NCS data may be equivocal, or in patients who decline EMG/NCS studies.

Action Potentials↗

F waves.

Explore the source record for details and available documents.

Electrodiagnosis↗

Cervical root stimulation at C5/6 excites C8/T1 roots and minimizes pneumothorax risk.

Needle electrical cervical root stimulation may be performed lateral to the C5/C6 or C7/T1 spinous process interspaces. Pneumothorax has been reported following C7/T1 root stimulation. We evaluated the efficacy of a modified C5/C6 stimulation technique in exciting C8/T1 roots in 15 normal subjects and 36 patients with motor neuron disease (204 procedures). No instances of a 50% or greater amplitude decline occurred. C5/C6 interspace stimulation, therefore, may be used to excite C8/T1 roots while minimizing pneumothorax risk.

Electric Stimulation↗

Right frontal lobe slow frequency repetitive transcranial magnetic stimulation (SF r-TMS) is an effective treatment for depression: a case-control pilot study of safety and efficacy.

Major depression may result from decreased left frontal lobe function with respect to the right. Fast frequency repetitive transcranial magnetic stimulation (FF r-TMS) excites the underlying cortex whereas slow frequency repetitive transcranial magnetic stimulation (SF r-TMS) causes cortical inhibition. Left frontal FF r-TMS attenuates major depression whereas the inhibitory effects of right frontal SF r-TMS are unknown. This study tested the hypothesis that right frontal SF r-TMS would treat depressed patients with minimal effect on controls. A psychiatrist administered the Beck depression inventory and Hamilton D depression rating scales to eight depressed patients and six controls before and after the treatment protocol. Eight sessions of 100 right frontal lobe SF r-TMS were given at motor threshold and 0.5 Hz over a 6 week period. No adverse outcomes were noted in either group. A significant antidepressant effect was noted in depressed patients on the Beck and Hamilton D depression rating scales (p<0.05). No change on either scale was noted in the controls. In conclusion right frontal lobe SF r-TMS is a safe, non-invasive treatment for major depression that deserves further investigation.

Adult↗

Root stimulation improves the detection of acquired demyelinating polyneuropathies.

Thirty-one patients with a presentation compatible with an acquired demyelinating polyradiculoneuropathy were prospectively evaluated for proximal conduction block using root stimulation (RS) of cervical and/or lumbar roots. These same techniques were applied to 78 controls (40 pathological). Proximal conduction block was noted in 20/31 cases and none of the controls. Only 7 of 31 cases met published demyelinating criteria. Intravenous immune globulin therapy was completed by 21/31 patients and 20/21 responded. RS is superior to published electrophysiologic criteria for identifying demyelinating polyneuropathies and predicting who will respond to treatment. RS should be performed in all patients suspected of having an acquired demyelinating polyneuropathy when traditional nerve conduction studies criteria are nondiagnostic. RS reliably predicts those likely to respond to immunosuppressive therapy.

Adult↗

A 60-year-old woman with weakness, fatigue, and acute respiratory failure: case report and discussion of the differential diagnosis.

A 60-year-old woman with chronic progressive fatigue, diurnal somnolence, proximal muscle weakness, and dyspnea developed acute respiratory failure when given supplemental oxygen. Hypoventilation secondary to neuromuscular dysfunction was suspected by the critical care specialist. Neurologic consultation and supportive laboratory evaluations led to the diagnosis of acid maltase deficiency, which was confirmed by muscle biopsy. The discussion includes a literature review that describes the pathophysiology and treatment of this rare muscle enzyme deficiency disorder. Acid maltase deficiency should be suspected in any adult presenting with hypoxemia, fatigue, and acute respiratory failure.

Acute Disease↗

Fabry's disease presenting as syncope, angiokeratomas, and spoke-like cataracts in a young man: discussion of the differential diagnosis.

A 44-year-old male with a remote history of skin lesions and cataracts presented with subacute onset of syncope. The presentation and the differential diagnosis in this case of Fabry's disease are discussed. The pathophysiology, diagnosis, clinical manifestations, and treatment of this disorder are discussed, with a review of the literature. Fludrocortisone acetate therapy resulted in a reduction in the patient's syncopal event frequency. Serum enzymatic assay and skin biopsy are useful in the diagnosis of Fabry's disease. We advocate a conservative approach to the oculocutaneous symptoms and suggest appropriate interventions for the renovascular and autonomic nervous system complications of this disorder.

Adult↗