Sleep and periodic limb movements in corticobasal degeneration.

Corticobasal degeneration (CBD) exhibits distinct features of akinesia, the 'alien limb' sign and cortical myoclonus. We report a 63-year old woman with a history of CBD for 18 months who was studied twice using all-night polysomnography with an interval of 13 months. Both recordings revealed frequent periodic arm and leg movements predominantly during non-REM sleep. To our knowledge this has not been described in a patient with CBD so far. Similar to a previous report we found REM sleep without atonia (RWA) in all REM episodes. However, the patient showed RWA and some non violent movements that fulfilled the diagnosis of subclinical REM sleep behavior disorder only in the second investigation. These observations may be due to the underlying degenerative process that involves not only cortical but also thalamic and brainstem structures.