PubMed · 3679949
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H Stowell. 1987. Localizing scalp-conducted electrical potentials.. https://doi.org/10.1016/0167-8760(87)90010-9
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Interactions between sentences and the individual words that comprise them are reviewed in studies using the event-related brain potential (ERP). Results suggest that, for ambiguous words preceded by a biasing sentence context, context is used at an early stage to constrain the relevant sense of a word rather than select among multiple active senses. A study comparing associative single-word context and sentence-level context also suggests that sentence context influences the earliest stage of semantic analysis, but that the ability to use sentence context effectively is more demanding of working memory than the ability to use single-word contexts. Another indication that sentence context has a dramatic effect on single-word processing was the observation that high- and low-frequency words elicit different ERPs at the beginnings of sentences but that this effect is suppressed by a meaningful sentence context.
Neurophysiological investigations are indispensable tools in evaluating and quantifying functional impairment of spinal cord structures and adjacent nervous tissue in any disorder of the spine accompanied by neurological symptoms. In this review the relevant neurophysiological techniques will be briefly described and their differential value for diagnosis and prognosis of spinal cord damage discussed. Typical case reports of spine disorders at different spinal levels are presented to illustrate results and interpretations of neurophysiological investigations.
From 1983-1992 CEP monitoring in spinal cord injury (SCI) was performed in 312 cases, of them 9 were acute SCI and 303 chronic (cervical spine 57, dorsal 88, T11-L1 136 and lumbar 31). 179 cases were complete paraplegia and 133 incomplete paraplegia. CEP were negative in 175 of 179 complete paraplegia, and the correct diagnosis rate was 97.8%. The false positive rate was 2.2%. The changes of CEP in 133 cases of incomplete paraplegia were prolonged latent period and/or decrease in amplitude. Negative CEP occurred in 5 cases, making the false negative rate to be 3.75%. In case of cervical SCI, the CEP of median nerve was positive when C5 segment was intact, while radial nerve CEP was positive as C6 segment was intact. The ulnar nerve CEP was mostly involved in lower cervical spine injury and in central type of SCI because it is composed of C7, C8 and T1 segments. In dorso-lumbar junction, there was the lower end of the spinal cord with its nerve roots, therefore, the CEP of T11-L1 SCI was performed by stimulating femoral, posterior tibial and common peroneal nerves to decrease false negative rate in incomplete paraplegia. Positive CEP in the femoral nerve and negative in tibial and peroneal nerves indicate recovery of nerve roots of lumbar plexus and no recovery of the spinal cord. Positive CEP in femoral, tibial and peroneal nerves represents recovery of the spinal cord and its roots and negative CEP in all three nerves indicate complete SCI, no recovery of spinal cord and its roots.(ABSTRACT TRUNCATED AT 250 WORDS)