Neuroimaging tools in the severely injured brain
Bringing neuroimaging tools closer to diagnostic use in the severely injured brain
Nicholas D. Schiff
Brain 130, 2482-2483 (2007)
Abstract
In a vanguard study reported in this issue of Brain,
Coleman et al. (page 2494) used hierarchically organized
passive language tasks and functional magnetic resonance
imaging (fMRI) to study 14 patients with severe brain
injuries. Functional levels of the study subjects ranged
across a spectrum from vegetative state to minimally conscious
state, and severe disability following emergence from
the minimally conscious state. The investigators assessed
three levels of speech processing beginning with comparisons
of auditory stimuli to a silent baseline, followed by
comparisons of intelligible speech versus unintelligible
noise, and finally advancing to high-level semantic contrasts
using English sentences containing words with either high
or low ambiguity of interpretation. Notably, their findings
revealed evidence of preserved higher level language
processing among a subset of three patients meeting the
criteria for vegetative state. Taken together with an earlier
single-subject study of one of the vegetative state patients
(Owen et al., 2006), the results support further developing
these and other neuroimaging tools to aid the difficult
diagnostic assessments of patients with severe brain injuries
(Laureys et al., 2004; Schiff, 2006).
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