Biomaterial Database

Middle latency auditory evoked potentials in intensive care patients and normal controls. 1995

G Litscher

Department of Anesthesiology, University of Graz, Austria.

Evoked potentials have been introduced into intensive care unit to objectively measure parameters of coma. In particular, auditory brainstem evoked potentials have been useful for localizing brainstem dysfunction in comatose patients. The middle latency auditory evoked potentials (MLAEPs) believed to be a response of subcortical auditory radiations and the primary auditory cortex. MLAEPs were measured in 40 adults (mean age 24.9 +/- 2.9 years; range: 19-34 years) with normal hearing and in 102 intensive care patients (mean age: 48.4 +/- 18.9 years; range: 14-86 years) under the influence of biological variables. Latencies (control group, mean +/- SD: V = 5.74 +/- .29 ms, N0 = 9.11 +/- 1.74 ms, P0 = 12.94 +/- 1.87 ms, Na = 17.23 +/- 1.77 ms, and Pa = 29.22 +/- 3.43 ms), amplitudes (control group, mean +/- SE: N0-P0 = 2.00 +/- .34 microV, P0-Na = 3.88 +/- .67 microV, Na-Pa = 2.83 +/- .29 microV) and the amplitude ratio (control group, mean +/- SE: P0-Na/Na-Pa = 1.53 +/- .39) were calculated. In the control group in both females and males, right-sided stimulation produced shorter average MLAEP latencies and higher amplitudes than left-sided stimulation (Pa-right 28.26 +/- 3.53 ms; Pa-left 30.17 +/- 3.33 ms). MLAEPs showed significant differences according to sex but did not depend significantly on age. A temperature dependence was found for the latency of wave V (short latency AEP), which was prolonged at lower temperatures and for the amplitude Na-Pa, which was increased at decreased temperatures between 38.9 and 35.4 degrees C. There was a significant association between the amplitude Na-Pa and PO2 (P = .017). Alterations of PCO2 in the range of 26 to 54 mmHg did not influence the MLAEPs. Also, renal dysfunction or hepatic dysfunction and alterations of mean arterial pressure (range: 50-102 mmHg) did not affect MLAEP latencies and amplitudes significantly. Increases in latencies and decreases in amplitude were seen in sedated patients. These results in intensive care patients suggest that the combination of early AEP (acute phase) and MLAEP (post acute phase) may be useful to monitor comatose patients.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011930	Reaction Time	The time from the onset of a stimulus until a response is observed.	Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D003422	Critical Care	Health care provided to a critically ill patient during a medical emergency or crisis.	Intensive Care,Intensive Care, Surgical,Surgical Intensive Care,Care, Critical,Care, Intensive,Care, Surgical Intensive
D005260	Female		Females
D006259	Craniocerebral Trauma	Traumatic injuries involving the cranium and intracranial structures (i.e., BRAIN; CRANIAL NERVES; MENINGES; and other structures). Injuries may be classified by whether or not the skull is penetrated (i.e., penetrating vs. nonpenetrating) or whether there is an associated hemorrhage.	Frontal Region Trauma,Head Injuries,Head Trauma,Occipital Region Trauma,Parietal Region Trauma,Temporal Region Trauma,Craniocerebral Injuries,Crushing Skull Injury,Forehead Trauma,Head Injuries, Multiple,Head Injury, Minor,Head Injury, Open,Head Injury, Superficial,Injuries, Craniocerebral,Injuries, Head,Multiple Head Injuries,Occipital Trauma,Open Head Injury,Superficial Head Injury,Trauma, Head,Craniocerebral Injury,Craniocerebral Traumas,Crushing Skull Injuries,Forehead Traumas,Frontal Region Traumas,Head Injuries, Minor,Head Injuries, Open,Head Injuries, Superficial,Head Injury,Head Injury, Multiple,Head Traumas,Injuries, Minor Head,Injuries, Multiple Head,Injuries, Open Head,Injuries, Superficial Head,Injury, Craniocerebral,Injury, Head,Injury, Minor Head,Injury, Multiple Head,Injury, Open Head,Injury, Superficial Head,Minor Head Injuries,Minor Head Injury,Multiple Head Injury,Occipital Region Traumas,Occipital Traumas,Open Head Injuries,Parietal Region Traumas,Region Trauma, Frontal,Region Trauma, Occipital,Region Trauma, Parietal,Region Traumas, Frontal,Region Traumas, Occipital,Region Traumas, Parietal,Skull Injuries, Crushing,Skull Injury, Crushing,Superficial Head Injuries,Temporal Region Traumas,Trauma, Craniocerebral,Trauma, Forehead,Trauma, Frontal Region,Trauma, Occipital,Trauma, Occipital Region,Trauma, Parietal Region,Trauma, Temporal Region,Traumas, Craniocerebral,Traumas, Forehead,Traumas, Frontal Region,Traumas, Head,Traumas, Occipital,Traumas, Occipital Region,Traumas, Parietal Region,Traumas, Temporal Region
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults