What EEG findings are characteristic of progressive supranuclear palsy (PSP)?

Updated: Oct 09, 2019
  • Author: Eli S Neiman, DO, FACN; Chief Editor: Selim R Benbadis, MD  more...
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Progressive supranuclear palsy (PSP) causes decreased ocular motility, rigidity, dementia, impaired postural reflexes, and, histologically, midbrain atrophy and abnormal tau deposition. Usually, the degree of dementia is not severe. The EEG in PSP may initially be normal but eventually shows increasing delta and theta activity, as was the most common finding reported by Fowler and Harrison in 1986. These authors found that the delta often was rhythmic with frontal accentuation.

Gross et al found a decrease in background frequency of 6-7 Hz and delta activity over the temporal regions. [25] Su and Goldstein et al found initial EEG patterns to be normal in 8 of 12 (67%) of patients with PSP. [26] With disease progression, they found background slowing and frontal intermittent rhythmic delta activity (FIRDA) (see below) in this population.

Frontal intermittent rhythmic delta activity (FIRD Frontal intermittent rhythmic delta activity (FIRDA).

Through the use of QEEG recordings in 6 patients with PSP compared with controls, Montplaisir et al found slowing over the frontal lobes in the waking state, with neuropsychological testing confirming this frontal lobe dysfunction. Abnormalities of sleep architecture with REM sleep abnormalities were seen as well.

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