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Biomedical subjects

C Ertekin

Publications and source records attributed to C Ertekin.

At least 91 records · Page 5Linked to original sources
PubMed1983

Studies on the human spontaneous electromyelogram (EMycloG). I. Normal subjects.

Using an intrathecal recording technique, the spontaneous electrical activity (EMyeloG) of the spinal cord was recorded in 25 normal human subjects. Very fast, continuous, irregular activity was analysed from the lumbo-sacral or cervical enlargement of the spinal cord after excluding volume-conducted potentials such as ECG and EMG. It was demonstrated that these spontaneous action potentials could be divided into two basic groups: (a) negative-positive diphasic waves, and (b) positive monophasic or positive-negative diphasic waves. Both waves were less than 50 microV and shorter than 10 msec. Their discharge rates were irregular, changing from time to time and from case to case. It is proposed that these spontaneous EMyeloGs recorded from normal human subjects are similar to those of 'background activity' described in the cat. Therefore they may share the same origin.

Electromyography↗
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↗
PubMed1982

Reflex erector spinal responses in disorders of the central nervous system.

In 64 patients with various central and peripheral nervous system disorders, the lumbar erector spinal muscle responses evoked by electrical stimulation of the brachial plexus at Erb's point or of the posterior tibial nerve in the popliteal fossa while standing were recorded. These responses were either absent or delayed in patients with involvement of the posterior columns. The latency of the responses was the same in patients with cerebellar syndromes, Parkinsonism, spastic hemiparesis or vestibular ataxia as in normal subjects. The size of the responses was diminished in patients with cerebellar syndromes and increased in those with Parkinsonism and spastic hemiparesis as compared with normal subjects.

Adolescent↗
PubMed1981

Bulbocavernosus reflex in benign hypertrophy of the prostate.

Electrically induced bulbocavernosus (BC) reflexes were investigated in 47 patients with benign prostatic hypertrophy and the possible harmful effects of prostatectomy on the pudendal nerve branches were followed up in 30 of the patients using the same method. BC reflex obtained by electrical stimulation of the glans penis did not differ significantly from the normal value in bulbocavernosus and external urethral sphincter muscles whether or not patients had been operated on. It was concluded that there is no reason to believe in the existence of somatic involvement of the pudendal nerve branches in prostatic hypertrophy, or that suprapubic prostatectomy could harmfully affect such somatic nerve fibers.

Aged↗
PubMed1981

Erector spinae muscle responses while standing.

In 55 normal adult subjects standing erect, stable EMG responses could be recorded from the lumbar erector spinae muscles in response to unilateral sudden are abduction produced by single electrical stimuli applied to the brachial plexus at Erb's point, or to knee and ankle movement produced by stimuli to the posterior tibial nerve in the popliteal fossa.

Adolescent↗
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↗
PubMed1980

Effect of continuous vibration on sural nerve action potentials.

The effects of continuous vibration on sural nerve action potentials were investigated in 15 subjects. The results show that continuous vibration applied to the sural nerve innervated skin area produces an amplitude reduction of the sural nerve action potentials on both painless and painful stimulation conditions. This amplitude decrease is attributed to an impulse blockage of the large diameter afferent nerve fibers.

Action Potentials↗
PubMed1979

Bulbocavernosus reflex in patients with conus medullaris and cauda equina lesions.

The clinical value and practical application of the electrically induced BC reflex was investigated in 40 patients with traumatic or compressive lesions of the conus medullaris or cauda equina. It was shown that the BC reflex was either absent or delayed depending upon the invovlement of the sacral 2--4 spinal and radicular segments. The latency of the BC reflex was normal in patients with mainly epiconus and lumbar cord involvement. The loss of the BC reflex in the acute period of traumatic lesions was an adverse prognostic sign while the presence of the reflex whether or not delayed, indicated a more benign final outcome of sphincter and sexual reflex disturbances. In chronic progressive compression, the latency of BC reflex was often delayed.

Cauda Equina↗
PubMed1978

Comparison of the human evoked electrospinogram recorded from the intrathecal, epidural and cutaneous levels.

In 30 patients (17 of whom had a clinically normal spinal cord) spinal cord potentials evoked by peripheral nerve stimulation were studied with computer averaging techniques in order to compare the intrathecal, epidural and skin records. In epidural and skin records, segmental spinal cord potentials either recorded from lower cervical or lower thoracic intervertebral levels often had similar shapes and latencies, especially with regard to the first component of the intrathecally recorded responses. The second slow component became less significant and was even absent in some cases. The amplitude of the first component was on average 33% of that recorded intrathecally when recorded epidurally and only 10% when recorded from the skin. In three cases potentials of very prolonged onset latency were recorded epidurally or cutaneously while in the same cases intrathecal records resulted in potentials with normal latencies. Cervical tract responses at the C6--7 intervertebral level after stimulation of the posterior tibial nerve were studied by the 3 recording methods. Epidural and skin records failed to reveal such a response regularly, while intrathecal recording invariably provided the cervical tract response. The 3 recording methods were discussed with respect to clinical applications and research. It can be stated with some reservation that epidural and skin surface recording techniques could be exploited it one could know the time of arrival segmental afferent inputs at the spinal cord.

Adolescent↗
PubMed1978

Effect of continuous vibration on nociceptive flexor reflexes.

The effects of continuous segmental vibration on the biceps femoris (BF) nociceptive flexor reflexes elicited by painful electrical stimulation of the sural nerve at the ankle were investigated in 25 normal subjects. During vibration of 100 Hz frequency, applied either on ipsilateral or contralateral foot skin, the nociceptive BF flexor reflexes increased in amplitude. Marked facilitation was prolonged even 20 minutes after vibration ceased. Pain sensation described by subjects did not change significantly except that radiation of pain was reduced in some cases. The results could not be explained by current views of reflex sensitisation, dishabituation, or the gate control theory.

Adult↗
PubMed1976

Bulbocavernosus reflex in normal men and in patients with neurogenic bladder and/or impotence.

The bulbocavernosus reflex was investigated electrophysiologically in 14 normal adult male subjects and in 80 patients with neurogenic bladders and/or impotence due to various neurological causes as well as in patients with functional impotence. The glans penis was stimulated superficially by single electrical shocks and the reflex responses were recorded from the bulbocavernosus (BC) and the striated anal sphincter muscles by means of concentric needle EMG electrodes. In all normal subjects, the BC reflex was recorded from the BC muscle as a stable and constant response having a mean latency of 36.1 msec. A response from the external anal sphincter was obtained in only 21% of the subjects investigated. In 13 patients with cauda equina lesions, the BC reflex was either absent or was present with a prolonged latency. Twenty-two patients with polyneuropathy of various causes were also investigated; in these patients the latency of the BC reflex was significantly greater than in the normal controls, but the most abnormal results were obtained in cases of alcoholic polyneuropathy. In the 19 cases of spinal cord disease with spasticity the BC reflex response was very intense, often with after discharges but latency values were within normal limits. In the 16 cases with functional impotence, the BC reflexes were basically normal; but in 3 cases, the threshold of the reflex was significantly raised, and in 1 case a prolonged latency was observed. The value and the practical application of the BC reflex in the BC reflex in the differential diagnosis of bladder dysfunction and of impotence was stressed.

Adolescent↗
PubMed1976

Studies on the human evoked electrospinogram. I. The origin of the segmental evoked potentials.

Evoked potentials from the human spinal cord were studied in 39 normal volunteers. Intrathecal recordings from lower cervical and lower thoracic intervertebral levels were made after the supramaximal stimulation of the median, ulnar and posterior tibial nerves, respectively. It was shown that the segmental cord potentials varied in shape and size according to the spatial relationship between the position of the electrode tip and the spinal cord and roots within the vertebral canal. Three main types of segmental evoked responses were obtained. One of them was recorded behind the cord dorsum and around the midline, and was composed of fast, sharp early, and slow, late components. This was called a CD potential and its first component was related to the activity of the ascending dorsal funiculus fibres. The second evoked response was the DR potential, and this triphasic compound action potential of very high amplitude and longer duration had no remarkable late component. It was recorded when the tip of the intrathecal electrode was lateral to the midline within the vertebral canal, and was then related mostly to activity of the spinal roots. Another kind of potential was called PH potential. It had a very small triphasic spike and two later components with prominent negativities being higher than the first spike. This potential might be related to the electrode tip position facing, and close to, the posterior horn of the spinal gray matter. Late components of the segmental evoked potentials were related to the pre- and post synaptic activity of the horizontally oriented fibre within the segmental gray matter of the posterior horn.

Adult↗
PubMed1976

Studies on the human evoked electrospinogram. II. The conduction velocity along the dorsal funiculus.

The propagation velocity of the ascending volleys along the dorsal funiculus of the human spinal cord was studied in 31 normal volunteers. Intrathecal recordings from lower cervical and lower thoracic intervertebral levels were made after the supramaximal stimulation of the posterior tibial nerves. When the electrode tip was behind the cord dorsum at the cervical level, it was easily possible to obtain very clear triphasic compound action potential on stimulation of the posterior tibial nerve of one leg or both legs. This "Tractus Potential" was found to originate mainly from the dorsal funiculus fibres, i.e. Fasciculus gracilis. The maximal conduction velocity of the ascending afferent volley from the leg was then calculated to be, on average, 37 meters/sec between lumbar and cervical spinal enlargements. Intrathecal stimulation and recording of the spinal cord gave the distinct triphasic wave with low threshold. This was also found to be related to dorsal funiculus activity. In these intraspinal stimulations and recordings, very early small and some late long-lasting deflections appeared, especially in the lateral position of the intrathecal electrode.

Adult↗
PubMed1975

Conduction velocity along human nociceptive reflex afferent nerve fibres.

The conduction velocity along the nociceptive flexor reflex afferent nerve fibres was investigated in human subjects. The posterior tibal nerve was stimulated at two sites by single painful electrical shocks of 1.0 ms duration and with adequate intensity and the reflex EMG discharges were recorded from the short head of the biceps femoris muscle. The fastest reflex conduction velocity along the posterior tibial nerve between the ankle and the popliteal fossa was about 10-25 m/s. Thus the fastest flexor reflex afferent fibres associated with a painful sensation were thought to be included in the A-delta group of cutaneous afferent nerve fibres.

Adolescent↗