Objective: To evaluate the prognostic value of somatosensory evoked potentials (SEPs) in severe traumatic brain injury (TBI) considering both ‘awakening’and disability. Methods: SEPs were recorded in 60 severe TBI w...Objective: To evaluate the prognostic value of somatosensory evoked potentials (SEPs) in severe traumatic brain injury (TBI) considering both ‘awakening’and disability. Methods: SEPs were recorded in 60 severe TBI with duration of acute coma > 7 days. N20-P25 amplitudes, their side-to-side asymmetry and CCT were measured. SEPs on each hemisphere were classified as normal (N), pathological ( P) or absent (A). ‘Awakening’and disability were assessed after at least 12 mo nths using Glasgow Outcome Scale (GOS). SEP predictive value was compared with G CS and EEG reactivity. Results: Seventy-five percent regained consciousness. 29 /60 had a good outcome (GOS 4-5) and 31/60 had a bad outcome (GOS 1-3). Accord ing to the ROC curve, SEP findings were classified in 3 grades. Grade I (NN, NP) had PPV of 93.1%for ‘awakening’and 86.2%for good outcome. Grade III (AA) ha d PPV of 100%for bad outcome and 72.7%for ‘awakening’. Grade II (PP, NA, PA) was associated with the wider range of outcome. A multivariate analysis includi ng SEP grading, GCS and EEG reactivity did not increase the percentage of cases prognosticated by SEP alone. Conclusions: We confirm the high predictive value o f SEPs in TBI, which is greater than GCS and EEG reactivity.Indeed, SEP grades I and III were able to predict the correct prognosis in more than 80%of severe T BI. Therefore, SEPs should be used more widely in the prognosis of severe TBI.Si gnificance: Differently from post-anoxic, in post-traumaticcoma the presence o f normal SEPs has a favourable predictive value both for ‘awakening’and disabi lity. We think that in literature enough attention has still not been paid to th is finding.展开更多
Objective: To test the hypothesis that the N10 far field potential in median nerve somatosensory evoked potentials is generated by the motor axons by examini ng patients with amyotrophic lateral sclerosis (ALS). Metho...Objective: To test the hypothesis that the N10 far field potential in median nerve somatosensory evoked potentials is generated by the motor axons by examini ng patients with amyotrophic lateral sclerosis (ALS). Methods: Subjects were 5 A LS patients showing pronounced or complete denervation of median inner vated s mall hand muscles. We evaluated N10 over scalp, and proximal plexus volleys (PPV s) at lateral or anterior cervical electrode. Results: N10 and PPVs were definit ely preserved for every ALS subject. N10 amplitudes of ALS subjects were even si gnificantly larger than control subjects. In one ALS patient completely lacking motor axons, N10 was larger than the largest one among control subjects. Conclus ions: Present results clearly indicate that N10 is not predominantly generated b y motor axons but by the whole median nerve dominated by sensory axons. We propo se a theory that N10 is a junctional potential generated by the entrance of the median nerve into bone at the intervertebral foramen, producing a positive pole at the non cephalic reference electrode. Significantly larger N10 in ALS subjec ts may be due to the lack of cancellation by slower motor axons. Significance: T he hypothesis that N10 is generated by motor axons is refuted, and a new theory of its generation is presented.展开更多
文摘Objective: To evaluate the prognostic value of somatosensory evoked potentials (SEPs) in severe traumatic brain injury (TBI) considering both ‘awakening’and disability. Methods: SEPs were recorded in 60 severe TBI with duration of acute coma > 7 days. N20-P25 amplitudes, their side-to-side asymmetry and CCT were measured. SEPs on each hemisphere were classified as normal (N), pathological ( P) or absent (A). ‘Awakening’and disability were assessed after at least 12 mo nths using Glasgow Outcome Scale (GOS). SEP predictive value was compared with G CS and EEG reactivity. Results: Seventy-five percent regained consciousness. 29 /60 had a good outcome (GOS 4-5) and 31/60 had a bad outcome (GOS 1-3). Accord ing to the ROC curve, SEP findings were classified in 3 grades. Grade I (NN, NP) had PPV of 93.1%for ‘awakening’and 86.2%for good outcome. Grade III (AA) ha d PPV of 100%for bad outcome and 72.7%for ‘awakening’. Grade II (PP, NA, PA) was associated with the wider range of outcome. A multivariate analysis includi ng SEP grading, GCS and EEG reactivity did not increase the percentage of cases prognosticated by SEP alone. Conclusions: We confirm the high predictive value o f SEPs in TBI, which is greater than GCS and EEG reactivity.Indeed, SEP grades I and III were able to predict the correct prognosis in more than 80%of severe T BI. Therefore, SEPs should be used more widely in the prognosis of severe TBI.Si gnificance: Differently from post-anoxic, in post-traumaticcoma the presence o f normal SEPs has a favourable predictive value both for ‘awakening’and disabi lity. We think that in literature enough attention has still not been paid to th is finding.
文摘Objective: To test the hypothesis that the N10 far field potential in median nerve somatosensory evoked potentials is generated by the motor axons by examini ng patients with amyotrophic lateral sclerosis (ALS). Methods: Subjects were 5 A LS patients showing pronounced or complete denervation of median inner vated s mall hand muscles. We evaluated N10 over scalp, and proximal plexus volleys (PPV s) at lateral or anterior cervical electrode. Results: N10 and PPVs were definit ely preserved for every ALS subject. N10 amplitudes of ALS subjects were even si gnificantly larger than control subjects. In one ALS patient completely lacking motor axons, N10 was larger than the largest one among control subjects. Conclus ions: Present results clearly indicate that N10 is not predominantly generated b y motor axons but by the whole median nerve dominated by sensory axons. We propo se a theory that N10 is a junctional potential generated by the entrance of the median nerve into bone at the intervertebral foramen, producing a positive pole at the non cephalic reference electrode. Significantly larger N10 in ALS subjec ts may be due to the lack of cancellation by slower motor axons. Significance: T he hypothesis that N10 is generated by motor axons is refuted, and a new theory of its generation is presented.
