Rhythmic Coma in Children

Abstract

We describe a syndrome of rhythmic coma in children that consists of an invariant, nonreactive, diffuse cortical activity of a specific frequency, such as alpha, beta, spindle, or theta, recorded from a comatose child. We report 11 cases of children who were found to be in rhythmic coma during their acute illnesses. Their ages ranged from 2 to 15 years, and their diagnoses included encephalitis, head trauma, seizures, near drowning, brain tumors, stroke, and metabolic derangements. The specific frequency of the electroencephalographic pattern, ie, alpha, beta, spindle, or theta, did not influence the outcome. The clinical outcome appeared to depend on the primary disease process rather than the electroencephalographic finding. The prognosis of alpha-frequency rhythmic coma as well as of rhythmic coma in general was better in children than in adults. The pathophysiology in children may be similar, ie, the interruption of reticulothalamocortical pathways by metabolic or structural abnormalities, but the expression of this deafferentation may be more varied in the developing brain. Thus, we propose the term rhythmic coma as a unified concept for alpha, beta, spindle, and theta coma in children.

Favorable outcome from alpha coma in a 15-year-old with traumatic brain injury

“…Kaplan et al [2] in a meta-analysis of 36 patients with alpha coma found that 11 of these had concomitant beta (> 13 Hz) activity. Horton et al [10] found that EEG patterns of coma are more varied in children. In our patient, the predominant frequency was 8−9 Hz.…”

“…A repeat 16-channel EEG on day 16 showed persistence of intermittent diffuse alpha activity with a mixture of other frequencies. EEG monitoring by cerebral function analyzing monitor for 48 hours (day 16 to day 18) showed prominent activity in the alpha frequency band (8)(9)(10)(11)(12)(13). No paroxysmal activity was noted in either routine EEG or in the cerebral function-analyzing monitor monitoring.…”

“…Alpha coma refers to an electroencephalographic pattern predominating in the alpha frequency band (8)(9)(10)(11)(12)(13) and present in unresponsive patients [1,2]. The most common etiologic factors of this pattern are hypoxic-ischemic encephalopathy, encephalitis, head trauma, metabolic disorders, and drug overdose [1].…”

Head Trauma

“…18-4). [93][94][95] If the pattern can be interrupted by the application of external stimuli, the prognosis is considered better than if the pattern is unreactive. [93][94][95] If the pattern can be interrupted by the application of external stimuli, the prognosis is considered better than if the pattern is unreactive.…”

“…92 It has been reported in traumatized children as well as adults. Horton and colleagues 95 found that the frequency of the invariant, nonreactive, diffuse cortical activity seen in children with coma was not confined to a single frequency and proposed the term rhythmic coma as a unified concept for alpha, beta, spindle, and theta coma in children. Horton and colleagues 95 found that the frequency of the invariant, nonreactive, diffuse cortical activity seen in children with coma was not confined to a single frequency and proposed the term rhythmic coma as a unified concept for alpha, beta, spindle, and theta coma in children.…”