To describe the clinical characteristics of a cohort of patients that developed Cyclic Alternating Pattern of Encephalopathy (CAPE) during long term encephalographic monitoring (LTM).

The 2021 updated ACNS Standardized Critical Care EEG Terminology introduced CAPE as a new term, defined by changes in background patterns each lasting at least 10 seconds and spontaneously alternating in a regular manner for at least 6 cycles. The clinical significance of CAPE is currently unknown.

This is a retrospective study on adult patients admitted to UF Health Gainesville from 10/1/2020-10/31/2020 that underwent LTM for evaluation of encephalopathy for 12 or more hours. If cyclic pattern was present on q-EEG analysis, one of two groups of two board-certified encephalographers independently reviewed the raw EEG to confirm CAPE. Chart review was performed to evaluate for patient clinical characteristics of interest.

During October 2020, 69 patients were admitted and underwent LTM monitoring for evaluation of encephalopathy at some point during their admission. Seventeen (25%) patients developed CAPE. Patient age ranged from 25-81 years (median 67 years). In terms of race, 5 patients were black, 1 was Asian, and 11 were white. Four patients were female and thirteen were male. Only 2 patients lacked primary CNS insult as reason for admission. Pre-existing neurologic comorbidities included seizures, stroke, dementia, sleep disorders, and history of VP shunt. Fifteen out of seventeen patients were in the ICU when CAPE was identified. In terms of outcomes, 3 patients died in the hospital, 3 were transferred to hospice, 3 were discharged to long term care facilities, and 8 were discharged home/short-term rehabilitation units.

CAPE is not an uncommon EEG finding in patients with encephalopathy, however, little information exists on its etiology or clinical significance.  A better understanding of the clinical factors associated with CAPE is needed to further investigate its implications and prognosis.