Who gets to decide?: Substitute decision making following severe brain injury with communication impairment.

Purpose: In our prior study (Malhi et al., 2021), we demonstrated that cognitive ability may be masked by communication impairments. We used binary choice (i.e., yes/no) neuropsychological tests to assess cognitive functioning in four patients with severe brain injury and communication impairments. In this study, we aimed to better understand the decision-making process of their substitute decision makers (SDMs). Methods: We interviewed SDMs - two SDMs were supporting patients in the minimally conscious state, one SDM was supporting a patient who had locked-in syndrome and was an augmentative communication user, and the last SDM was supporting a patient who was an alternative communication user. Results: SDMs were performing various roles ranging from making all decisions to simply being the vocal advocate (for the augmentative and alternative communication users). SDMs described heuristics they used to make decisions, and all identified auditory comprehension capabilities as being an important element for decision making. Conclusion: We argue that if mode of communication is established and utilized, and binary choice neuropsychological tests are used to ascertain cognitive functioning, SDMs may more confidently make low/medium stakes decisions based on the present condition and context, rather than solely on past wishes and values before capacity was in question.

Thinking without speaking: Neuropsychological testing with individuals who have communication impairments.

Cognitive ability may be masked by communication impairments. This study aimed to assess cognitive functioning using binary choice (i.e., yes/no) neuropsychological tests in patients with communication impairments. Four participants underwent neuropsychological testing. Two participants were in the minimally conscious state (MCS), one participant had locked-in syndrome and was an alternative communication user, and one participant was an augmentative communication user. There was better performance in all cognitive domains for the augmentative and alternative communication (AAC) users (who performed like the non-communication impaired normative data) compared to the MCS participants. However, using established yes/no communication methods, MCS participants performed above chance on a measure of memory and performance on measures of auditory comprehension was variable. Auditory comprehension appeared to be more influenced by working memory demands for the MCS participants than for the AAC users. For emotional functioning, the AAC users endorsed lower mood compared to the MCS participants. The results support the need to assess cognition, communication, as well as capacity in individuals with communication impairments with the consultation of a neuropsychologist and a speech-language pathologist.

Does visualisation help or hinder concrete word processing?

In an iconicity judgement task, participants were asked whether word pairs were iconic (e.g., nose-tongue; joy-sorrow) or reverse-iconic (e.g., tongue-nose; sorrow-joy), and an advantage for abstract word pairs (i.e., joy-sorrow) was found. Malhi and Buchanan proposed that this reverse concreteness, or abstractness, effect was the result of participants taking a visualisation/imagining (time-costly) approach towards the concrete word pairs and an emotional/intuitive (time-efficient) approach towards the abstract word pairs. This study tested this proposal by asking participants questions about strategy use (Experiment 1). In the forced-choice questions, all participants reported using a visualisation/imagining approach towards the concrete word pairs and most participants reported using an emotional/intuitive approach towards the abstract word pairs. In the open-ended responses, visual-spatial reasoning and real-life experience emerged as themes for the concrete word pairs and social norms and values emerged as themes for the abstract word pairs, adding to our understanding of the grounding of abstract words. In Experiment 2, participants were supplied with pictures as an aid to visualisation with the expectation that this would reduce the time required for concrete word processing. Supplying pictures made participants faster and more accurate at completing the task. Experiment 3 manipulated the type of visual aid by also supplying pictures that did not match the orientation of the word pairs. Participants were only more accurate when the pictures were in the correct and iconic spatial arrangement. A flexible abstractness and concreteness effects (FACE) theory is proposed which integrates symbolic and embodied accounts and introduces constructs such as direct and constrained imageability for concrete words and indirect and free imageability for abstract words.

A test of the symbol interdependency hypothesis with both concrete and abstract stimuli.

In Experiment 1, the symbol interdependency hypothesis was tested with both concrete and abstract stimuli. Symbolic (i.e., semantic neighbourhood distance) and embodied (i.e., iconicity) factors were manipulated in two tasks-one that tapped symbolic relations (i.e., semantic relatedness judgment) and another that tapped embodied relations (i.e., iconicity judgment). Results supported the symbol interdependency hypothesis in that the symbolic factor was recruited for the semantic relatedness task and the embodied factor was recruited for the iconicity task. Across tasks, and especially in the iconicity task, abstract stimuli resulted in shorter RTs. This finding was in contrast to the concreteness effect where concrete words result in shorter RTs. Experiment 2 followed up on this finding by replicating the iconicity task from Experiment 1 in an ERP paradigm. Behavioural results continued to show a reverse concreteness effect with shorter RTs for abstract stimuli. However, ERP results paralleled the N400 and anterior N700 concreteness effects found in the literature, with more negative amplitudes for concrete stimuli.