Cognitive dysfunction after central pontine myelinolysis

Central pontine myelinolysis (CPM) is a rare but increasingly recognized neurological disorder associated with a lesion of the central portion of the basis pontis and characterized by altered level of consciousness, seizures, pseudobulbar palsy, dysphagia, and quadriparesis. Until the advent of computerized tomography, CPM was considered fatal and discovered only at post-mortem. The case is reported of a 61-year-old, high-functioning, non-alcoholic man who developed CPM after liver transplantation. Neuropsychological evaluation documented many expected motoric deficits. More unforeseen was this patient's lingering amnestic syndrome and global lowering of many 'higher' cognitive processes, e.g. intelligence, reasoning, concentration, etc. The role of the brainstem in 'higher' cognitive functions is considered through four mechanisms: the reticular activating system, disruption of neocortical-ponto-cerebellar networks, the preliminary processing model, and through interruption of neurotransmitter pathways.