Brain activity in an end-stage ALS patient suggests the presence of an unresponsive wakefulness syndrome.
Sandra Frycz, Wiktor Więcławski, Marcin Skotniczny et al.
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Case in brief
A 42-year-old woman with bulbar-onset, end-stage ALS and no means of communication underwent EEG and audiological assessment for covert consciousness. EEG showed prominent prefrontal 1–3 Hz activity, poorly differentiated power spectra, and no event-related potentials or 40 Hz auditory steady-state responses. Otoacoustic emissions were absent, and auditory brainstem responses indicated severe to profound hearing loss. The findings provided no electrophysiological evidence of covert consciousness and showed a profile resembling unresponsive wakefulness syndrome.
What made this case unusual
The electrophysiological profile in end-stage ALS resembled unresponsive wakefulness syndrome rather than supporting the assumption of preserved cortical function in complete locked-in syndrome; severe to profound hearing loss was also identified.
Diagnostic / clinical pearl
In end-stage ALS without communication, absent auditory EEG responses should be interpreted alongside assessment of auditory pathway integrity; this patient had severe to profound hearing loss as well as evidence of severe cortical dysfunction.
Why it matters
The case supports considering impaired consciousness, rather than persistent complete locked-in syndrome alone, as a possible framework for understanding some patients after advanced ALS.