To explore how task and stimuli influence response accuracy in assessing functional communication in adults emerging from a Prolonged Disorder of Consciousness (PDOC).
Setting
Specialist post-acute brain injury assessment centre.
Subjects
Twelve adults (7 male; 5 female) emerging from PDOC, recruited consecutively between June 2021 and August 2023.
Methods
A prospective study exploring the impact of task and stimuli on response accuracy. Yes/no questions and spoken word-to-referent (colour/object) matching tasks were presented. Stimuli were controlled for psycholinguistic variables to reduce linguistic confounds in the assessment of consciousness. Accuracy was compared to a standard measure (visually based situational yes/no questions from the Coma Recovery Scale-Revised).
Results
Responses were most accurate for word-to-referent matching tasks compared to yes/no questions (t(23) = −6.49, P < 0.001, d = 1.33), with greater accuracy to colour than object stimuli (t(23) = 2.79, P = 0.01, d = 0.57). Participants also responded with greater accuracy to word-to-referent matching and yes/no questions involving colours and objects compared to the Coma Recovery Scale-Revised situational yes/no questions.
Conclusion
Task influences accuracy of responses in assessing return of consciousness. The advantage of colours over objects can be attributed to simpler visual processing and higher lexical frequency of these words. The current standard situational yes/no tasks from the Coma Recovery Scale-Revised resulted in lowest scores and should not be relied upon as the only measure of functional communication.
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