Say the opposite: Negation processing in agrammatic aphasia

GORAL, MIRA; JAICHENCO, VIRGINIA; MARÍA ELINA SÁNCHEZ; ALXATIB, SAM; LIBBEN, GARY

Filadelfia

Conferencia; Academy of Aphasia; 2022

IntroductionIt has been reported in the literature on aphasia that negation presents difficulties to persons with aphasia (PWA), and that the difficulties are typically ones of production rather than comprehension. For example, in a sentence anagram task, PWA had more errors in negative than in affirmative sentences. This has been observed in some languages but not others (Albustanji et al., 2013; Fyndanis et al., 2006; Rispens et al., 2001), a finding that researchers have attributed to cross-linguistic syntactic differences. We are not aware of studies that compare PWA’s ability to negate affirmative prompts to their ability to derive affirmatives from negative prompts. We aim to use this comparison to further our understanding of the source of negation processing difficulty in aphasia. MethodsParticipants: Fourteen people participated in the study. Six PWA (three Spanish speakers with severe agrammatic aphasia; one English speaker with mild agrammatic aphasia, and two English speakers with anomic aphasia) and eight neurologically-healthy people. Participants were 30-65 years old with ≥12 years of schooling. Procedure and materials: We designed two tasks: (1) Repetition task: a sentence was said aloud and the participants had to repeat it verbatim. E.g. prompt: The aunt is reading; target: The aunt is reading; (2) Say-the-Opposite task: a sentence is said aloud and the participants must produce the opposite sentence. E.g. prompt: The aunt is reading; target: The aunt is not reading. The tasks included sentences in six conditions that vary in (a) verbal aspect, (b) verb phrase complexity, and (c) type of negation (particle vs. adverbial/quantificational). For each condition, 16 stimuli were created (eight affirmative and eight negative), so each task had a total of 96 items.ResultsOf our six PWA, the three Spanish speakers and two of the three English speakers showed greater difficulty in the Say-the-Opposite task than in the Repetition task. The four participants with agrammatic aphasia demonstrated a directional asymmetry: they had greater difficulty converting negative prompts to affirmative than converting affirmative to negative (see Figure 1). Conclusions Our results show that PWA find greater difficulty deriving the affirmatives of negative sentences than the reverse, despite the apparent similarity of the two processes. In one the task involves omitting the negation particle (or replacing the negative adverb with its antonym), while in the other it involves adding negation (or replacing the positive adverb with its antonym). Our findings point to the complexity of the impairment of sentence derivation in agrammatism, showing a robust directionality effect across conditions. We discuss the implications of these findings in the context of earlier work on the comprehension and production of negation.