Post resuscitation prognostication by EEG in 24 vs 48 h of targeted temperature management.

OBJECTIVE: To test if prognostic performance is affected by prolonged targeted temperature management (TTM) in comatose out-of-hospital cardiac arrest patients using two recently proposed EEG pattern classification models. METHODS: In this sub-study of the "Target Temperature Management for 48 vs. 24 hand Neurologic Outcome after Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial", EEGs of 20-30 min duration were collected 24 h and 48 h after reaching the target temperature of 33 ±â€¯1 °C. We classified EEGs according to two EEG classification models by Westhall et al. ("highly malignant", "malignant" and "benign") and Hofmeijer et al. ("unfavorable", "intermediate" and "favorable"). We tested prognostic ability against 6 months functional outcome using the Cerebral Performance Category score. RESULTS: We recorded EEGs in 120 patients at 24 h and in 44 patients at 48 h. We found no difference in specificities or sensitivities of the two models between the two TTM groups (all p-values >0.19) or in prognostication at 24 h compared to 48 h (all p-values >0.13), except for the presence of EEG reactivity favoring prognostication at 24 h (p < 0.001). Being classified in the "benign" or "favorable" category was strongly associated with good outcome with specificities of 100% (90-100) and 97% (85-100) for the Westhall and Hofmeijer models respectively. CONCLUSIONS: We found no difference in the prognostic performance of the two studied EEG classification models during prolonged TTM for 48 h compared to standard duration, nor between EEG classification performed at 24 h versus 48 h after reaching target temperature. The two models performed best in good outcome prediction.

Evoked potential tests in clinical diagnosis.

BACKGROUND: Evoked potentials are used to detect conduction disturbances in the central nervous system. This paper provides an overview of the areas in which evoked potentials are used in clinical neurophysiological diagnostics, with the emphasis on coma and demyelinating disease. METHOD: The article is based on a literature search in PubMed and the authors' long experience of neurological and neurophysiological diagnostics. RESULTS: Somatosensory evoked potential (SEP) can be a reliable predictor of failure to regain consciousness as early as 24 hours after anoxic coma has occurred. If coma is caused by a brain trauma, cerebrovascular episode or other neurological disease, information about which sensory brainstem pathways are damaged can be obtained from somatosensory evoked potentials and brainstem auditory evoked potentials (BAEP), which can also be useful for planning rehabilitation. Normal SEP and BAEP findings in cases of coma caused by trauma are associated with a favourable prognosis. Visually evoked potential (VEP) can often reveal signs of a history of optic neuritis. SEP and BAEP can also reveal subclinical lesions in the central nervous system and be a supplementary diagnostic test for multiple sclerosis. INTERPRETATION: The clinical value of SEP and BAEP is high in coma cases. Evoked potentials are also important in intraoperative monitoring. The clinical value of VEP is high when a history of optic neuritis is a deciding factor for a multiple sclerosis diagnosis. Some selected patients who are being assessed for demyelinating disease will benefit from a full EP study.