Dynamic changes in sleep-related breathing abnormalities in bilateral paramedian mesencephalon and thalamus stroke: a follow-up case study.

BACKGROUND: Bilateral paramedian thalamic stroke is characterized by hypersomnia, vertical gaze palsy, amnestic alteration, and apathic state. Combined lesion of the paramedian thalamus and mesencephalon bilaterally is extremely rare. Little is known about the breathing disturbances of the particular region due to the lesion. The following describes the specific case of a woman, age 62, with bilateral paramedian thalamic and mesencephalic stroke. Initially, the patient's complaints exhibited altered vigilance and vertical gaze palsy. Notably, following the acute phase, fluctuating hypersomnia was detected. The MRI (brain) revealed an ischemic lesion in the medial part of the mesencephalon and paramedian thalamus, bilaterally. AIMS: The aim of the present study is to elucidate the involvement and characteristics of sleep-related breathing abnormalities in the clinical manifestation of the combined paramedian thalamic and mesencephalic stroke. METHODS: Polysomnographic recordings were accomplished seven times with 1-week interval between the consecutive recordings, toward investigating the early changes of sleep and sleep-related breathing abnormalities. RESULTS: Sleep structure examination featured a decrease in N3 and REM ratio and an increase in N1 and N2 ratio with minimal improvement during the recovery period. In contrast, significant changes were found in the breathing pattern: the initial central apnea dominance was followed by obstructive apneas with a gradual decrease of the total pathological respiratory events. CONCLUSION: In addition to the structural abnormality of the sleep regulating network, sleep-disordered breathing is another possible cause of hypersomnia in patients afflicted with the present localization of the lesion.

Diurnal alterations of brain electrical activity in healthy adults: a LORETA study.

EEG background activity was investigated by low resolution brain electromagnetic tomography (LORETA) to test the diurnal alterations of brain electrical activity in healthy adults. Fourteen right-handed healthy male postgraduate medical students were examined four times (8 a.m., 2 p.m., 8 p.m. and next day 2 p.m.). LORETA was computed to localize generators of EEG frequency components. Comparing the EEG activity between 2 p.m. and 8 a.m., increased activity was seen (1) in theta band (6.5-8 Hz) in the left prefrontal, bilateral mesial frontal and anterior cingulate cortex; (2) in alpha2 band (10.5-12 Hz) in the bilateral precuneus and posterior parietal cortex as well as in the right temporo-occipital cortex; (3) in beta1-2-3 band (12.5-30 Hz) in the right hippocampus and parieto-occipital cortex, left frontal and bilateral cingulate cortex. Comparing the brain activity between 8 p.m. and 8 a.m., (1) midline theta activity disappeared; (2) increased alpha2 band activity was seen in the left hemisphere (including the left hippocampus); and (3) increased beta bands activity was found over almost the whole cortex (including both of hippocampi) with the exception of left temporo-occipital region. There were no significant changes between the background activities of 2 p.m. and next day 2 p.m. Characteristic distribution of increased activity of cortex (no change in delta band, and massive changes in the upper frequency bands) may mirror increasing activation of reticular formation and thus evoked thalamocortical feedback mechanisms as a sign of maintenance of arousal.