Psychometric and EEG changes after carotid endarterectomy.

The influence of carotid stenosis and its surgical treatment on brain function is still poorly defined. We therefore performed a study to assess psychometric and quantified EEG findings after carotid endarterectomy (CEA). Sixty-nine non-demented patients (aged 72 ± 7 years) with severe carotid stenosis (≥ 70%) eligible for CEA were studied. Forty patients (group A) had unilateral stenosis, and 29 patients (group B) had bilateral stenosis. Before and 5 months after CEA all the patients were evaluated by the Trail Making Test A, the Symbol Digit Test, and spectral EEG analysis. At baseline, compared to group A, group B patients performed slowly the Trail Making Test A (Z: 1.45 ± 1.4 vs. 0.76 ± 1.3; p < 0.05), but not the Symbol Digit Test (Z: 0.83 ± 1.38 vs. 0.64 ± 1.26; p = 0.59). Altogether, the patients with at least one abnormal psychometric test were 29% (group A: 26%; group B: 33%, p = 0.56). The EEG did not differ significantly between patients of group A compared to group B. After CEA, psychometric tests improved (mean Z score from 0.73 ± 1.12 to 0.45 ± 1.15, p < 0.05). The improvement was similar in group A and B. The EEG mean dominant frequency improved only in group B patients and it was related to the improvement in psychometric tests (r = 0.43, p = 0.05). Low psychometric performance was detectable in about 1/ 3 of non-demented patients with severe carotid stenosis. CEA improved mental performance and, in patients with severe bilateral stenosis, accelerated the EEG frequency.

Prognostic benefit of the addition of a quantitative index of hepatic encephalopathy to the MELD score: the MELD-EEG.

BACKGROUND & AIMS: A slowed electroencephalogram (EEG) is indicative of the presence of hepatic encephalopathy (HE). Since HE is not reflected in the MELD score and is an important prognostic parameter, we assess the prognostic benefit of the addition of an EEG-based HE index to the MELD. METHODS: Three hundred and ninety-two patients with cirrhosis underwent EEG and automated determination of its mean dominant frequency (MDF). MELD was calculated at the time of EEG recording. Patients were monitored for up to 18 months in relation to the occurrence of death/transplantation. The prognostic value of the stand-alone/combined MELD and MDF was calculated using standard survival analysis techniques. Patients transplanted for hepatic decompensation were considered dead on the day of transplantation, those transplanted for hepatocellular carcinoma were censored. The findings were validated using a split-sample technique (reference group: n = 256; test group: n = 136). During the follow-up period, 107 patients died/were transplanted for hepatic decompensation. RESULTS: Both MELD and MDF predicted mortality on Kaplan-Meier analysis, and both were independent predictors of mortality on a Cox model. Based on Cox regression parameters, a novel prognostic index was devised, as follows: MELD-EEG = 0.087*MELD-0.306*MDF. On ROC curve analysis, MELD-EEG had higher prognostic accuracy in predicting 12- and 18-month mortality compared to MELD (P = 0.016 and P = 0.018, respectively). In addition, it had better sensitivity and reduced the misclassification rate for given levels of specificity. On validation, no significant differences were observed between the reference/test groups. CONCLUSIONS: The addition of an automatically obtained EEG-based index improves the prognostic accuracy of the MELD score.

The effect of aging on auditory components of event-related brain potentials.

OBJECTIVE: To describe auditory perceptual, pre-attentive, attention-related and cognitive processes along lifespan in normal people by a simple auditory oddball paradigm easily usable in clinical practice. METHODS: ERPs were recorded in 72 normal subjects. Four blocks of tones were delivered (20% rare 2,000 Hz and 80% frequent 1,000 Hz). In the former two blocks, subjects performed a concomitant distracting visual search task (distracted condition); in the latter two blocks, they had to attend the occurrence of the rare tones (active condition). Latency and amplitude of ERPs were analyzed according to age, gender, educational level and repetition. RESULTS: N100 amplitude was greater in active than in distracted condition. MMN amplitude decreased with age. N2b and P300 latencies increased with age, while their amplitudes decreased. Females produced greater P300 than males. In the elderly, P300 latency was found to be longer in the second block than in the first one. CONCLUSIONS: N100 and MMN were found to be less affected by age than N2b and P300. When repeated, P300 showed increased latency in elderly subjects. SIGNIFICANCE: The protocol detected the higher influence of aging on late cognitive processes than on the perceptual and pre-attentive ones. Age-adjusted normative data were produced.