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Biomedical subjects

E L Logigian

Publications and source records attributed to E L Logigian.

86 records · Page 5Linked to original sources
PubMed1989

Motor neuropathy with multifocal conduction blocks.

We describe a patient with a chronic, symmetric, monophasic, acquired, pure motor, demyelinating polyneuropathy. Electrodiagnostic studies showed the presence of multifocal conduction blocks in motor nerves at sites not prone to compression. A sural nerve biopsy was normal. The patient responded to immunosuppressive therapy and plasma exchange. We postulate that this disorder is an unusual variant of chronic inflammatory polyradiculoneuropathy.

Adolescent↗
PubMed1988

Motor unit synchronization in physiologic, enhanced physiologic, and voluntary tremor in man.

Synchronization between pairs of single motor units simultaneously recorded from wrist extensor muscles was quantitated in 3 normal subjects during physiologic tremor (PT), beta-adrenergically enhanced physiologic tremor (EPT), and fast voluntary wrist flexion-extension movements mimicking tremor (VT). Cross-correlation histograms generated from the two spike trains of each motor unit pair demonstrated central or paracentral peaks in 13/19 recordings during PT, 22/36 during EPT, and 6/7 during VT. Relative peak area was used as a quantitative index of synchronization between the two motor units of each pair. It was lowest in PT, progressively increased in EPT as tremor amplitude increased, and highest in VT. In PT and lower amplitude EPT, the synchronization indexes were higher between motor units that discharged at the same or nearly the same frequency. In contrast, in higher amplitude EPT and VT, motor units with different firing frequencies were sometimes strongly synchronized as a consequence of double discharges in faster-firing motor units that had burst repetition rates in the range of slower-firing motor units discharging as singlets. Greater motor unit synchronization with increasing tremor amplitude in EPT may be secondary to a simultaneous increase in muscle spindle afferent activity from the tremulous muscle. Greatest synchronization in VT presumably reflects near maximal supraspinal and segmental common synaptic input onto motoneurons that generate VT. These results support a longstanding hypothesis that synchronization of motor units is the physiological basis for higher amplitude tremor.

Electromyography↗
PubMed1988

Nervous system involvement in Fabry's disease: clinicopathological and biochemical correlation.

A detailed neuropathological and biochemical study was performed to evaluate the accumulation of ceramide trihexoside within the central and peripheral nervous systems of 2 patients with Fabry's disease. Luxol fast blue-staining lipid was noted in the leptomeninges and in the choroidal stroma; biochemical studies showed increased quantities of ceramide trihexoside in the cerebrospinal fluid. The permeable blood-brain barrier regions of the central and peripheral nervous systems contained increased quantities of ceramide trihexoside. Some central nervous system nuclei associated with autonomic function were also noted to store lipid. Other areas of increased ceramide trihexoside accumulation included specific cortical and brainstem structures. Possible sources for this selective accumulation of ceramide trihexoside within the central and peripheral nervous system include transport of glycolipid from the systemic vascular network and retrograde transsynaptic glycolipid transport.

Brain↗
PubMed1988

Stretch-induced spinal accessory nerve palsy.

Left spinal accessory nerve palsy occurred in a young man when he quickly turned his head to the right while his shoulders were pulled down by heavy hand-held objects. Electrophysiologic studies demonstrated partial axonotmesis of the spinal accessory nerve branches innervating the sternocleidomastoid and upper and middle trapezius and complete axonotmesis of spinal accessory branches to the lower trapezius. There was a separate, although functionally minor, cervical plexus innervation of the lower trapezius.

Accessory Nerve Injuries↗
PubMed1988

Reversible proximal conduction block underlies rapid recovery in Guillain-Barré syndrome.

Three patients with Guillain-Barré syndrome underwent electrophysiological examination prior to and during a period of rapid clinical recovery. In each case, improved strength of the abductor digiti minimi coincided with electrophysiologic evidence of a marked reversal of proximal conduction block. In contrast, the degree of distal conduction block remained relatively unchanged after stimulation at the wrist, elbow, axilla, and Erb's point. These findings indicate that rapid motor recovery, early in the course of Guillain-Barré syndrome, can result from reversal of proximal conduction block and explains the often noted dissociation between clinical improvement and conventional distal nerve conduction studies.

Action Potentials↗
PubMed1987

Cervical root stimulation in the diagnosis of radiculopathy.

Cervical root stimulation (CRS) was compared with conventional EMG, nerve conduction, and late response studies in 34 patients with possible cervical radiculopathy. Cervical roots were stimulated by monopolar needles inserted into paraspinal muscles, recording compound muscle action potentials in biceps, triceps, and abductor digiti minimi muscles. In 18 patients with clinical evidence of radiculopathy, EMG was abnormal in 11 (61%), but CRS was abnormal in all 18. Of 16 patients with symptoms but no signs of radiculopathy, EMG was abnormal in 5 (31%) and CRS was abnormal in 9 (56%).

Action Potentials↗
PubMed1987

Lumbrical sparing in carpal tunnel syndrome: anatomic, physiologic, and diagnostic implications.

Motor axons supplying lumbrical muscles are less severely affected than axons supplying thenar muscles in the carpal tunnel syndrome; sometimes lumbrical motor fibers are less affected than digit 2 sensory fibers. This pattern is consistent with compression of both the anterior and posterior aspects of the median nerve in the carpal tunnel because nerve fibers responsible for thenar, lumbrical, and digit 2 functions lie in an anterior-posterior gradient within the distal median nerve. Recognition of lumbrical sparing supports the electrodiagnosis of carpal tunnel syndrome when the distal latency to thenar muscles or the palm-to-wrist mixed median nerve conduction velocity is normal.

Action Potentials↗
PubMed1986

Myoclonus epilepsy in two brothers. Clinical features and neuropathology of a unique syndrome.

We report 2 brothers with progressive ataxia, seizures, myoclonus, supranuclear ophthalmoplegia, progressive visual loss and embolic strokes. The epilepsy and myoclonus came on many years after the onset of the ataxia. In the more severely affected brother the myoclonus was often unilateral and focal but ultimately involved both sides of the body. His sibling had only unilateral myoclonus after a contralateral middle cerebral artery stroke. When focal, persistent and unilateral, the myoclonus in both brothers was clinically similar to epilepsia partialis continua except that muscles of the trunk and proximal limbs were the most affected. It was exacerbated by movement of the affected part but was otherwise not stimulus sensitive. The more severely affected brother had a pigmentary retinopathy and a cardiac fibromyxoid valvulopathy. In his sibling, visual loss was not fully investigated and the heart was not examined at autopsy though he had a longstanding heart murmur. Neuropathological studies showed pancerebellar cortical atrophy, cell loss in the inferior olivary nuclei and old right middle cerebral artery infarctions in both brothers. Biochemical assays for known metabolic diseases were negative. We suggest that this syndrome represents a unique autosomal recessive form of progressive myoclonus epilepsy of unclear aetiology. It is distinguished from other familial myoclonus epilepsies by the presence of early onset cerebellar ataxia, supranuclear ophthalmoplegia, pigmentary retinopathy and possibly cardiac valvulopathy with subsequent cerebral emboli.

Adult↗
PubMed1985

Terminal electrocardiographic changes in brain-dead patients.

We analyzed ECGs of 18 brain-dead patients from the time of termination of ventilation until cessation of electrocardiographic activity. Gradual slowing of the atrial mechanism was followed by AV block or a gradually slowing junctional escape rhythm. Despite progressive failure of atrial and junctional pacemakers, none had a ventricular escape rhythm. There were three terminal rhythms: (1) atrial activity only, (2) slow junctional rhythm or sinus bradycardia, or (3) ventricular tachycardia (VT). A prolonged QT interval, corrected for rate, was related to later development of VT. One hypothermic and three euthermic patients had J waves.

Brain Death↗
PubMedDate not supplied

Electrophysiologic assessment of a median nerve injury in the palm.

In median nerve lesions of the hand, electrophysiologic evaluation of the second lumbrical muscle can help to differentiate between lesions of the common digital nerves and the proper digital nerves, as illustrated by this case report. Median nerve conduction studies to the second lumbrical muscle can be performed by placing an active recording electrode just radial to the midpoint of the third metacarpal and stimulating the median nerve at the wrist or elbow.

Accidents, Occupational↗