Table 1.

Clinical details of the FFI kindred^a

	FFI-Mother	FFI-Child
Clinical manifestations	Onset at 60 years Rapidly progressive dementia, becoming mute at 5 months after onset Sleep disturbance (−) Akinetic mutism (+) Total clinical duration: 14 months	Onset at 54 years Dysphagia and loss of appetite as an initial symptom Followed by insomnia and hypersomnolence, diplopia, ataxic gait and impotence Akinetic mutism (−) Total clinical duration: 13 months
Neurological examinations	2 months after onset Severe memory disturbance, rigidity and brisk deep tendon reflexes No cerebellar ataxia PSD (−) in EEG	7 months after onset Mild memory disturbance, cerebellar ataxia, brisk deep tendon reflexes Loss of deep sleep and marked reduction of REM sleep in polysomnography PSD (−) in EEG

^aClinical details of these patients have been reported elsewhere (Saitoh et al., 2010).