Sensory Conduction Time Research Articles

Peripheral and central delays in the cortical projections from human truncal muscles. Rapid central transmission of proprioceptive input from the hand but not the trunk.

In contrast to the cortical connections to and from the muscles of the hand, the transmission of an afferent volley from the intercostal muscles to the cerebral cortex takes approximately 10 ms longer than it takes a cortical motor volley to reach the muscle. This disparity in afferent and efferent cortical transmission times could be due to a slower peripheral conduction velocity of intercostal muscle afferents or a slower afferent conduction within the central nervous system. The present study derived peripheral and central conduction times for the truncal muscles from the onsets of the mechanically evoked intercostal and abdominal spinal reflexes and the onsets of the cortical sensory potentials. Mean latencies of the ipsilateral intercostal and abdominal reflexes (evoked and recorded in the mid-clavicular line) were 11.9 +/- 0.7 (SEM) ms and 13.7 +/- 0.9 ms, respectively; calculated peripheral conduction velocities were 69.4 +/- 4.1 m/s and 56.2 +/- 2.3 m/s (assuming equal velocities for the sensory and motor axons and an intraspinal delay of 1 ms). Central sensory conduction time (spinal cord to cortex) was calculated by subtracting the peripheral conduction times for the intercostal and abdominal afferents (5.5 +/- 0.3 ms and 6.4 +/- 0.4 ms) from the onsets of the cortical sensory potentials (19.4 +/- 0.8 ms and 25.3 +/- 12.3 ms); central sensory conduction times (14.2 +/- 1.7 ms and 18.6 +/- 2.3 ms) were 8-11 ms longer than central motor conduction times. These results demonstrate that peripheral conduction velocities of intercostal and abdominal afferents are not slow, and that, when compared with the extremities, there is a relatively long central conduction time for proprioceptive information from the trunk to the cerebral cortex.

Important Abnormalities in Recordings of Somatosensory Evoked Potentials in Coma

We have chosen six illustrations showing how much vital information can be obtained from median nerve SEPs during the first 24 hours in coma. With avulsion of brachial plexus roots there was loss of SEPs at the cervical cord and the scalp from the affected side. In a severe injury of the cervical cord there was preservation of brachial plexus potentials, while SEPs at the cervical cord were absent. After critical deterioration in a case of repeated subarachnoidal hemorrhage, scalp SEPs with very short latency occurred, which is a finding suggestive of destruction of cortical SEP generators heralding a fatal outcome. In a case of brain injury combined with central hyperthermia, there was initially a loss of scalp SEPs probably due to the combined effect of these factors. In a case of brain injury there were bifid peaks at the scalp level. It is important to assess central sensory conduction time only to the first scalp SEP, otherwise an erroneously abnormal state may be inferred. In a patient with clinical and EEG evidence of brain death there was a loss of far-field thalamic potentials at the neck. It is important to be aware of such presentations to be able to provide corroborative assurance for the assessment of prognosis.

Motor and sensory evoked potentials in progressive supranuclear palsy

Motor potentials evoked in the biceps, thenar, and tibialis anterior muscles by electrical stimulation of the scalp and of the spinal regions were recorded in 12 patients with progressive supranuclear palsy (PSP) and in a control group. Abnormalities of central motor conduction for at least one muscle were present in five patients (41.7%), characterized by a long illness duration. The central sensory conduction time of the median nerve was normal, but five patients showed a depressed frontal N30 wave. These findings support the possible occurrence of functional damage to the corticospinal tracts and to the supplementary motor area in PSP.

Neurophysiological evaluation of central-peripheral sensory and motor pudendal fibres

Extensive neurophysiological investigations were carried out in 18 healthy volunteer subjects, and 6 patients with neurological disease. The tests consisted of spinal and scalp somatosensory evoked potentials (SEPs) to stimulation of the dorsal nerve of penis/clitoris, motor evoked potentials (MEPs) from the bulbocavernosus muscle (BC) and anal sphincter (AS) in response to scalp and sacral root stimulation, and measurement of sacral reflex latency (SRL) from BC and AS. In the control subjects, the mean sensory total conduction time (sensory TCT), as measured at the peak of the scalp P40 wave was 40.9 msec (range: 37.8–44.2). The mean sensory central conduction time (sensory CCT = spine-to-scalp conduction time) was 27.0 msec (range: 23.5–30.4). Transcranial brain stimulation was performed by using a magnetic stimulator both at rest and during voluntary contraction of the examined muscle. Sacral root stimulation was performed at rest. Motor total conduction times (motor TCT) to BC and AS muscles were respectively 28.8 and 30.0 msec at rest, and 22.5 and 22.8 msec during contraction. Motor central conduction times (motor CCT) to sacral cord segments controlling BC and AS muscles were respectively 22.4 and 21.2 msec at rest, and 15.1 and 12.4 msec during contraction. The mean latencies of SRL were respectively 31.4 msec in the bulbocavernosus muscle and 35.9 msec in the anal sphincter. Combined or isolated abnormalities of SEPs, MEPs and SRL were found in a small group of patients with neurological disorders primarily or secondarily affecting the genito-urinary tract.

A study of the maturation of the somatosensory pathway by evoked potentials.

We investigated the somatosensory evoked potentials (SSEPs) in 62 healthy children, ten days to twelve years old. Our control group consisted of ten healthy adults, sixteen to thirty-six years old. The stimulus was applied at the median nerve at the wrist and the cerebral SSEPs were recorded by electrodes placed on the contralateral parietal scalp region, while for the cervical SSEP recording the electrodes were placed over the skin at the C6-C7 vertebral region. The reference electrode was placed at the FZ according to the 10-20 system. Our study revealed a significant change in the early components of the SSEPs (NI and PI) between groups of different ages. The latency and duration of the NI wave form and the latency of PI were inversely correlated with age. These changes in the early components of the SSEPs are most likely due to the gradual maturation of the afferent nervous system with age. From the difference in latencies between the peak of NI and the cervical SSEP we were able to calculate the sensory conduction time in the central nervous system and found a progressive decrease in relation to the increase of age. This is most likely due to the development of postnatal myelination of the sensory fibres of the central somatosensory pathway.

Carpal tunnel syndrome in athetoid-dystonic cerebral palsy.

We have observed several cases of carpal tunnel syndrome (CTS) in persons with athetotic-dystonic movement disorders. Since this association between CTS and athetotic-dystonic cerebral palsy is not mentioned in extensive clinical reports 1-14 we wish to present these cases and discuss their physiopathology. PATIENTS AND METHODS A patient with an athetotic-dystonic movement disorder complained of pain in the hand in the median nerve distribution. This incident prompted a search for persons with similar movement disorders to assess the presence of entrapment neuropathy. Neurophysiologic studies consisting of sensory and motor nerve conduction time (NCT) in median, radial, and ulnar nerves were performed in 16 patients. Diseases that are known predecessors as well as local causes of CTS 10 were ruled out by clinical examinations or roentgenograms, or at the time of operation. Generalized peripheral neuropathy was ruled out by multiple nerve examinations. The basis for the diagnosis of CTS included the

Sensory nerve stimulation and evoked cerebral potentials.

Cerebral potentials were evoked by stimulating sensory fibers of the median, ulnar, radial, musculocutaneous, sural, superficial peroneal, and saphenous nerves. The sensory nerve action potential was simultaneously recorded from these nerves, allowing comparison of peripheral and central sensory conduction times. Somatosensory potentials (SEPs) elicited by sensory nerve stimulation are of particular value in evaluating proximal segments of peripheral as well as central somatosensory pathways.

Apport de l'électromyographie a l'étude des lésions nerveuses du nerf cubital a la main: Le syndrome de compression de la branche motrice du nerf cubital

Standard electromyographic investigations: detection and stimulodetection; segmental motor nerve conduction rate, distal motor latencies (interphalangeal V and I short abductor muscles), and distal sensory (antidromic) conduction time, were used to explore seven cases of distal paralysis of the ulnar nerve. Results enabled differentiation of elective lesions of the deep motor branch from those of the ulnar nerve in Guyon's canal. These two types of lesion correspond to precise anatomical features: the channel between the pisiform and unciform bones on the one hand and Guyon's canal on the other. The electroclinical syndrome of the deep branch should be considered as a separate true canalicular syndrome. Treatment is by surgery in most cases.

Nerve Conduction Studies in Resorptive Arthropathies

Resorptive arthropathy (opera-glass hand) is a syndrome associated primarily with the collagen disease arthropathies. This unique destructive articular process has a resemblance to the neuropathic joint, but no clinical or pathological evidence for a neuropathy has been reported in the resorptive arthropathies. A study of sensory and motor nerve conduction times, as well as electromyography, in six cases of resorptive arthropathy have failed to demonstrate evidence of a neurologic abnormality in this disorder.

Hyperparathyroid Neuromuscular Disease.

Meeting Abstracts1 May 1973Hyperparathyroid Neuromuscular Disease.Bernard M. Patten, M.D., John Belizikian, M.D., Lawrence Mallette, M.D., Alan Prince, M.D., Gerald Aurbach, M.D., W. King Engel, M.D.Bernard M. Patten, M.D.Search for more papers by this author, John Belizikian, M.D.Search for more papers by this author, Lawrence Mallette, M.D.Search for more papers by this author, Alan Prince, M.D.Search for more papers by this author, Gerald Aurbach, M.D.Search for more papers by this author, W. King Engel, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-78-5-815_4 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptWe report the first detailed study of the neurological, electromyographic, and muscle biopsy findings in patients with hyperparathyroidism.Over 80% of our 16 patients presented with a distinct syndrome consisting of easy fatigability; weakness and atrophy of proximal muscles, particularly of the leg; tongue tremors; and normal or hyperactive reflexes. The presence or severity of weakness bore no relationship to the alteration of any serum ion measured, including calcium. The electromyograms showed short-duration, low-amplitude complex and, sometimes, polyphasic potentials mingled with high-amplitude, long-duration motor units. Motor and sensory nerve conduction times were normal. Muscle biopsies showed neurogenic atrophy of both... This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAffiliations: Bethesda, Maryland. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics 1 May 1973Volume 78, Issue 5Page: 815-816KeywordsAtrophyCalciumElectromyographyHyperparathyroidismMuscle biopsiesMusclesNervesNeuromuscular diseasesReflexesTongue Issue Published: 1 May 1973 PDF downloadLoading ...

Neurographic Studies Before, after, and During Operation for Median Nerve Compression in the Carpal Tunnel

Fifty hands with clinical symptoms and signs of compression of the median nerve in the carpal tunnel have been electrophysiologically analysed pre- and post-operatively by measuring the sensory and motor conduction times in the median nerve over the wrist and by comparing the results with the corresponding sensory and motor conduction times in the radial and ulnar nerves of the same hand. The series was divided into four groups according to the severity of the electrophysiological pre-operative findings. All groups showed postoperative shortening of the conduction times for the median nerve parallelling clinical improvement.For electrophysiological diagnosis of distal median nerve compression it seems more adequate to compare the sensory and motor conduction of the median nerve with the radial nerve sensory conduction and the ulnar nerve motor conduction in the same hand than the use of fixed “normal” limits or using the other hand as control.During some operations, recordings of sensory conduction time a...