Cognitive impairment and electroencephalographic alterations before and after liver transplantation: What is reversible?

Abstract

The influence of liver transplantation (LT) on mental performance is debated, as is the role of pretransplant overt hepatic encephalopathy (OHE). The aim of this study was to evaluate the time course of the neuropsychological and electroencephalogram (EEG) features of patients with cirrhosis before and after LT with respect to prior OHE. The study population included 65 patients with cirrhosis on the transplant waiting list; 23 had a history of OHE. Each patient underwent an extensive psychometric assessment (10 tests, including paper and pencil tests and a computerized test) and an EEG before and 9 to 12 months after LT. For a subgroup of 11 patients, the assessment was also performed 3 and 6 months after LT. EEGs were analyzed spectrally, and the mean dominant frequencies were obtained. Both psychometric tests and EEGs improved 9 to 12 months after LT. Patients with a history of OHE before LT had worse cognitive performances (P < 0.001) and EEG performances in comparison with their counterparts with a negative history. They also showed greater cognitive improvement after LT (P < 0.01); however, their global cognitive performance remained slightly impaired (P < 0.01). After LT, EEGs normalized for 98% of the patients (P < 0.01), regardless of any history of OHE. In the subgroup of patients evaluated every 3 months, psychometric and EEG findings showed deterioration at 3 months and subsequently steady improvements from 6 months onward. In conclusion, both neuropsychological and EEG performances had significantly improved 1 year after LT. Patients with a history of OHE showed greater improvements after LT than patients with a negative history, but their global cognitive function remained slightly worse; in contrast, EEGs normalized in both groups. Liver Transpl 20:977-986, 2014. V C 2014 AASLD.

Postoperative cognitive dysfunction after liver transplantation

“…The type cognitive assessment throughout the studies includes several components that are affected in MHE, such as attention, concentration, psychomotor speed and verbal and visuospatial short-term memory. Therefore, most of the studies consider also the persistence or worsening of preexisting cognitive deficits as POCD [27][28][29]22,[37][38][39][40][41][42], in accordance with the statement that successful LT should remove HE [27,31,32]. MHE predicts OHE [43], but it is often clinically missed [44].…”

“…It is well know that MHE has high prevalence in patients with liver cirrhosis, ranging from 10% to 70% [28,29,22,37]. Instead, the prevalence of POCD across the studies ranges from 0% to 50% (see Table 1).…”

“…It has also been suggested that a history of HE is associated with persisting neurological deficits 18months following LT [27], as measured after by the psychometric hepatic encephalopathy score (PHES) battery [27]. In patients with liver cirrhosis, the presence of preoperative HE seems to be an important risk factor for the persistence of cognitive deficits after LT [28,29]. Several previous studies have demonstrated substantial improvement in neuropsychological tests months to years after LT [22,[30][31][32][33][34], especially for those patients with overt HE (OHE) [27], even if the return-to-normal value is less frequent [35].…”

The Clinical Relevance of Minimal Hepatic Encephalopathy - A Critical Look

“…Several studies have shown that cognitive function increases after orthotopic liver transplantation (OLT) [32,33,34]. However, some of the patients remain impaired, and thus attempts have been made to find out if significant cognitive impairment after liver transplantation depends on the grade of HE prior to HE or a history of HE.…”

“…However, some of the patients remain impaired, and thus attempts have been made to find out if significant cognitive impairment after liver transplantation depends on the grade of HE prior to HE or a history of HE. Campagna et al [32] showed an improvement of cognitive function as well as EEG after liver transplantation in a study comprising 65 patients with cirrhosis. At the time of inclusion into the study none of the patients had overt HE, while 32% had mHE.…”