Bilateral paramedian thalamic syndrome: abnormal circadian wake-sleep and autonomic functions.

OBJECTIVES To describe wake-sleep and body core temperature (t degrees ) rhythm abnormalities in two patients with bilateral paramedian thalamic calcifications. METHODS Patients underwent (18F)FDG PET scans and 24 hour polygraphic recordings of wake-sleep and t degrees. RESULTS PET showed bilateral thalamic hypometabolism in both patients with additional basal ganglia or mesiolateral frontal and cingular hypometabolism. Wake-sleep studies showed abnormal sleep organisation and in the case with frontal and limbic PET hypometabolism, pre-sleep behaviour associated with "subwakefulness" EEG activities, lack of EEG spindles and K complexes, and features of status dissociatus. The t degrees rhythms showed increased mesor in both (37.4 degrees C and 37.75 degrees C) and inverted rhythm in one patient. CONCLUSIONS Paramedian thalamic structures and interconnected, especially frontal and cingular, areas play a part in the organisation of the wake-sleep cycle and attendant autonomic functions.