Clinical characteristics of all FFI patients
| Parameter | Common | Frequent | Less frequent | Rare |
| Cluster A (sleep-related symptoms) | ||||
| Insomnia | 87.0% | |||
| Sleep-related involuntary movements | 46.6% | |||
| Sleep-related dyspnoea | 25.2% | |||
| Laryngeal stridor | 32.1% | |||
| Cluster B (neuropsychiatric symptoms) | ||||
| Rapidly progressive dementia | 83.2% | |||
| Psychiatric symptoms | 66.4% | |||
| Ataxia | 56.5% | |||
| Pyramidal sign | 25.2% | |||
| Parkinsonism | 36.6% | |||
| Myoclonus | 29.8% | |||
| Bulbar syndrome | 25.2% | |||
| Diplopia | 22.1% | |||
| Cluster C (progressive sympathetic symptoms) | ||||
| Sweating | 55.0% | |||
| Hypertension | 33.6% | |||
| Weight loss | 30.5% | |||
| Tachycardia | 24.4% | |||
| Irregular breathing | 16.8% | |||
| Hyperthermia | 19.8% | |||
| Others* | 13.0% |
*Others in cluster C represent constipation, urinary retention and sexual dysfunction.
FFI, fatal familial insomnia.;