The diagnosis of fatal familial insomnia (FFI) is first suggested by rapidly progressive cognitive impairment (dementia) along with behavior or mood changes, ataxia and sleep disturbances. Further diagnosis will include a sleep study and possibly a PET scan to confirm thalamic hypometabolism (meaning the thalamus in the brain is less active than it should be). The recommended PET scan is the fluorodeoxyglucose positron emission tomography (FDG-PET).
Genetic testing can confirm the diagnosis, but in the United States is only available if the person meets one of the following three criteria:
Family history of FFI
Abnormal sleep study or PET scan (consistent with strong suspicion of FFI)
Diagnosis of FFI (usually through a combination of sleep study results and PET scan results)
Carrier testing for at-risk relatives and prenatal testing are possible for families with a confirmed diagnosis of FFI.
Last updated: 11/30/2016
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