Studies examining executive and pragmatic functioning

In chsq>ter two it was emphasised Aat problems in pragmatic functioning following TBl have tended to be explained m terms o f impaired executive processes» alAough this relationship has mainly been supported using conventional Imguistic and cognitive tests. There have been few stuAes exploring broader aspects o f pragmatic functioning. A large^ number o f stuAes looking at communication problems in patients wiA right hemiqnhere lesions have used tasks tzqnpmg wider aspects o f pragmatics (alAough as noted m disinter two Ae cognitive aspects o f Aese problems have been given little attention). For example» patients wiA right hemisphere damage have been shown to have problems pafbrm ing tasks involving Ae mterpretation o f indirect requests (FolA 1987; Hirst al 1984; Weylman et al 1989), humour (BArle al 1986; Brownell and Gardeier 1988)» and sarcasn (Kaplan d al 1990). Impairment on tasks requiring holistic and context-dqpendent inferences sudi as deriving Ae main point has also been reported (e g. Hough 1990; Brownell et al» 1986).

A small numbe* o f TBl stuAes have adopted similar meAodologyr to explore Ae contribution o f cognitive deficits (particularly aspects o f executive functioning) m impaired pragmatic functioning

1.15, ]. Comprehension o f pragmatic inference

TBl padaits have been found to have difficulty widi pragmatic comprdiension. McDonald and van Sommers (1993) studied two TBl patients with executive im pairm eit They found that while both patients recognised the inferred aspect an indirect request (e g. "Can you pass the salt?”) one patient had difficulty understanding the role o f the literal meaning. These same two patients also had difficulty comprdiending non-convendonal indirect speech acts in the form o f sarcastic commoits (McDonald, 1992b). This finding was supported by a lator study by McDonald and Pearce (1996), In diis study ten TBl patients (six severe cases) and twenty healthy controls were required to read pairs o f literally inconasteit sentences. For example, person A said “What a great football game” and person B said “Sorry 1 made you come”. It was considered that die only way this could be seen as meaninghil was if one o f statemeits was interpreted as opposite to v^at it literally asserts and was thus viewed a sarcastic com m eit They then asked participants to answer either yes or no to four questions, whidi judged whedier they viewed die statement as insincere. For example, “Did person A think die game was bad?” They found diat TBl patieits performed more poorly compared to controls on these itens.

It was argued that diis poor interpretation o f sarcasm could be accounted for by conceptual problems related to poor performance on a test o f executive fimctioning and was also consistent with die traditional Gricean view o f pragmatic fimctioning (see c h u ter two). It was noted that the recognition o f sarcasm requires the processing o f the literal meaning o f the remark and dren a rejection o f this in preference for the infm ed meaning. Patients who are stimulus bound should be incapable o f seeing beyond the hteral meaning. The researchers also found that the addition o f attitudinal information in die speakers voice (in an audiotaped version) did not improve performance, even in those patients who were capable o f using diis

type o f information. Thus it was argued that diis finding did not support the E dioic' model o f pragmatic functioning (see diapter two).

Bara et al (1997) studied pragmatic inferoice in thirteai severe TBl patients and healdiy controls. Participants watched brief videotaped interactions betweei characters. The interactions ended with direct and indirect speech acts. They adopted an open-ended response format in vdiich participants wore asked to fieely report dieir understanding o f the interaction and say vihat t h ^ diought would happen next When responses were unclear, three intepr^adons o f die inteacdon (inferendal, liteal and out o f context) were presented to the pardcipant at the same time. They needed dioose the infereidal interpretadon to pass die itan. It was found diat the TBl padents could successfully comprehend more basic* indirect speech, whereas other indirect responses including deceit were poorly understood. It was suggested that indirect speech acts might vary along a continuum in terms o f their inferendal difficulty. Unfortunately, die relationship with pafbrm ance on neuropsychological tests was not examined in this study.

1.15.2. Production o f pragmatic inference

There is some evidence to suggest that TBl patients have d ifficu lt producing conversational inference. McDonald and van Sommers (1993) found that TBl patioits who had executive impairmoit were unable to produce effective hints diat only alluded to die actual request by subde irmuendo. It was argued diat this was pardy due to an inability to refiiain fiom stating their true intention. In a more recent stud^ this finding was associated with neuropsydiological measures o f disinhibition (McDcmald and Pearce, 1998).

1.15.3, Interpretation o f social appropriateness

It is important to note that in addition to the comprdiension and production o f pragmatic inferoice (indirect speech), successful pragmatic understanding also requires broader appreciation o f the social appropriateness o f information, taking into account social knowledge and contextual factors. This issue has not been studied in TBÏ patients. Studies in patients with right hemisphere lesions have given some consideration to this issue. For example, Rdiak et al (1992) found that patients with right hemisphere lesions (including anterior and posterior), in comparison to healdiy controls^ had difficulty interpreting and judging videotaped convesations, whidi violated aspects o f the Gricean maxims. Brownell et al (1997) also found that relative to healthy controls, patients with right hem iqihee lesions (usually involving the middle cerebral artery distribution) showed decreased use o f famiharity variables when choosing formal over informal labels.