Brain mapping analysis in patients with hepatic encephalopathy

Abstract

Topographical analysis of cerebral electrical activity was performed in 44 patients with hepatic encephalopathy. These patients were classified in 5 groups according to clinical criteria. Eight healthy subjects were used as a control group. All were studied in an awake, eyes closed, condition and some [Control Group (CG), Group 0 (G0), Group 1 (G1) and Group 2 (G2)] also in an awake, eyes open, condition. The awake, eyes closed, maps showed marked differences in the power spectral density (PSD) of the different bands, when comparing normal subjects with patients with several degrees of hepatic encephalopathy. These differences were related to the degree of clinical involvement, mainly in the alpha and delta PSD bands. The combination of a decreased alpha PSD, increased delta PSD, and decreased mean dominant frequency (MDF) allowed a clear discrimination between the different clinical groups. The differences observed between awake, eyes closed, and awake, eyes open, conditions were especially helpful to discriminate between CG subjects and G0, G1 and G2 patients.

Spectral and dynamic electroencephalogram abnormalities are correlated to psychometric test performance in hepatic encephalopathy

“…Topographical changes have been observed in previous studies of HE based on multichannel EEG [28][29][30]. The most consistent finding was anteriorization and dissociation of the posterior basic alpha rhythm with increasing severity of HE [30].…”

Spatio-temporal decomposition of the electroencephalogram in patients with cirrhosis

“…Although the diagnosis of hepatic encephalopathy has centred on changes in the EEG mean frequency, various topographical changes have also been observed in this patient population [13][14][15], including 'anteriorization' of the posterior basic rhythm [13]. This is characterized by extension from the occipital towards the parietal and central derivations and is a feature of the wake-sleep transition [16][17][18] and a number of pathological and pharmacological states [19][20][21][22][23][24].…”

“…The main electrophysiological criterion for the diagnosis of hepatic encephalopathy is slowing of the posterior basic rhythm from the alpha range (8)(9)(10)(11)(12)(13) towards the theta (4-7 Hz) and delta (1)(2)(3)(4) ranges [5][6][7][8][9]. The reported diagnostic sensitivity of the EEG varies from 43% to 100% in patients with overt hepatic encephalopathy [3,10].…”

“…The majority of EEGs recorded in healthy individuals are dominated by a basic rhythm, in the alpha frequency range (8)(9)(10)(11)(12)(13), which is concentrated in the posterior areas of the scalp [4]. This rhythm is easily distinguished in the majority of healthy adults but can be difficult to identify when the EEG is of low voltage or is dominated by fast activity [4].…”

Clinical Neurophysiology of Hepatic Encephalopathy

“…4 In agreement with this finding, previous data-based on less accurate EEG mapping technique-suggested an increase the central-frontal alpha. 5 Accordingly to Kullmann et al 6 the very initial stage of HE may be also characterized by an increase in frontal beta activity. However, as a rule, beta activity decreases in more severe HE.…”