Biomedical subjects

Y Sarica

Publications and source records attributed to Y Sarica.

21 records · Page 2Linked to original sources

PubMed1983

Studies on the human spontaneous electromyelogram (EMyeloG). II. Patients with peripheral nerve, root and spinal cord disorders.

Using an intrathecal recording technique the spontaneous electromyelogram (EMyeloG) was recorded in 44 patients having peripheral nerve, spinal root and lower motor neurone disorders (17 cases), suprasegmental spinal cord disorders (18 cases) and diffuse involvement of the posterolateral funiculus or spinal ganglia (9 cases). In the first 17 cases, labelled as 'afferent group,' the spontaneous EMyeloG was significantly reduced, parallelling the paucity of afferent signals entering the spinal cord. However, the spontaneous EMyeloG was found to be normal in cases with the diffuse anterior horn cell involvement and motor polyneuropathy. In the second 18 cases labelled as 'efferent group,' the spontaneous EMyeloG was more prominent and the amplitude and frequency of the spontaneous cord potentials were significantly increased. Especially in patients with spastic paraparesis various peripheral afferent stimuli could produce more significant facilitation of the EMyeloG in the 'efferent group' than in normal subjects. In the third group labelled as 'mixed group' a different type of abnormal spontaneous action potentials was observed in addition to increase of the spontaneous EMyeloG. These potentials were positive or mainly positive and their duration was long, being 10-25 msec. It was concluded that the human spontaneous EMyeloG recorded from an intrathecal electrode probably originates from the interneurones of the posterior horns, facilitated by peripheral afferent inputs and inhibited by suprasegmental descending pathways, especially the pyramidal tract.

Cerebellar Ataxia↗

PubMed1983

Studies on the human spontaneous electromyelogram (EMyeloG). III. Spontaneous spinal cord activity of the cat relevant to the human spontaneous EMyeloG.

The spontaneous electromyelogram (EMyeloG) was investigated in 16 cats, some after laminectomy and some by a percutaneous intrathecal technique similar to the human approach. Small diphasic negative-positive waves at less than 50 microV, with short durations, were consistently recorded from the posterior aspect of the spinal cord in both laminectomized and intact cats. It was demonstrated that this kind of background activity is mainly located within the posterior halves of the spinal cord and is strictly dependent on the peripheral inputs producing excitability changes in the gray matter of the posterior horn. Monophasic positive waves of larger amplitude were often recorded from the anterior halves of the spinal cord in both types of recording. However, the amplitude of the background activity of spontaneous EMyeloG was smaller in the percutaneous approach and negative sharp waves (NSWs) of large amplitude were never seen in these intact cats. NSWs were only observed in the majority of the laminectomized cats and were facilitated after spinalization. It was proposed that when the central and peripheral nervous system are intact in awake states, it is impossible to see NSWs either in human subjects or in cats.

Action Potentials↗

PubMed1980

Electrophysiological evaluation of the afferent spinal roots and nerves in patients with conus medullaris and cauda equina lesions.

The clinical value and practical application of the lumbosacral evoked electrospinogram (Espg) and somatosensory cerebral evoked potentials (SEP) were investigated in 52 patients with conus medullaris or cauda equina lesions. It was shown that the destruction or compression of the conus/cauda equina region by traumatic fracture and dislocation of upper lumbar vertebrae, by midline herniation of the nucleus pulposus and by tumoral mass, produced significant reduction in amplitude and delay in latency of Espg recorded just above the lesion site, and the SEP behaved in a similar way. The degree of abnormality was found to be in accord with the severity of clinical sensorimotor deficits in the legs. Tumoural compression caused more significant delay in evoked responses than traumatic injury. From the diagnostic point of view, Espg and SEP were useful in showing latent and manifest involvement of the lumbosacral sensory roots and these are discussed in relation to other electrodiagnostic tests.

Adolescent↗