Robert S. Pierce

The role of context in facilitating syntactic decoding in aphasia

This study assessed the ability of aphasic listeners to use linguistic context to facilitate the comprehension of complex syntactic structures. Fourteen aphasic subjects were presented with reversible active and reversible passive sentences in each of three conditions: isolation; a semantically neutral prior-sentence context; and a semantically supportive prior-sentence context. Following presentation of the contextual and target sentences the subjects were asked a question that assessed their appreciation of the subject/object relationship in the target sentence. A forced-choice-response paradigm was employed. The results indicated that those subjects who had the most difficulty comprehending reversible passive sentences in isolation were able to benefit from the supportive contexts. The comprehension of active sentences was not facilitated by the contexts. These results were interpreted with respect to the comprehension strategies used by aphasic listeners to integrate information from different sources.

Contextual influences in aphasia: effects of predictive versus nonpredictive narratives

The influence of prior linguistic predictive and nonpredictive context on the comprehension of reversible passive sentences was investigated in 16 adults with aphasia. Eight subjects were classified as fluent and 8 as nonfluent. Subjects were presented with the sentences in isolation and preceded by nonpredictive and predictive contextual paragraphs. The overall results indicated that the subjects benefited significantly from the prior contextual narratives regardless of whether the paragraphs were predictive or nonpredictive. There were no significant differences between the two subject groups. The significant facilitation generated by the nonpredictive context suggests that redundancy of information may play a role in comprehension.

Semantic attribute knowledge in adults with right and left hemisphere damage

Abstract This study investigated the nature of semantic attribute knowledge in subjects with left and right hemisphere brain damage and subjects with no brain damage. The relationship between attribute knowledge and both auditory comprehension level and naming skills was also studied. Subjects completed a sorting task involving high, mid, and low frequency of occurrence nouns and high (HI) and low importance (LI) attributes. Subjects also named pictures of the stimulus nouns. While the identification of HI attributes remained intact, left and right hemisphere-damaged subjects exhibited equivalent reductions in identification of LI attributes across frequency levels. In contrast, the left hemisphere-damaged subjects were significantly more impaired on comprehension and naming measures than were the right hemisphere-damaged subjects. Comprehension and naming performance demonstrated a systematic relationship with attribute knowledge in the left hemisphere-damaged subjects only.

Single word comprehension in aphasia: Influence of array size, picture relatedness and situational context

Abstract The influence of three variables on single word comprehension in 11 aphasic subjects was assessed using a picture pointing task. The variables were: the number of pictures displayed, the relationship among the pictures and the presence of a situational context. The results indicated that, when the pictures were unrelated, increasing the number of pictures did not affect accuracy until eight pictures were present. When the pictures were related based on a common situational theme but still displayed in a standard format, increasing their number impaired performance when six or eight pictures were present. Introducing a situational context impaired performance beginning with four pictures. Most of the scores on the experimental measures correlated significantly with scores from the word discrimination subtest of the Boston Diagnostic Aphasia Examination but not from the recognizing common words subtest of the Minnesota Test for Differential Diagnosis of Aphasia or the Token Test. Clinical and theor...

The interactive nature of auditory comprehension in aphasia

This study assessed the interaction between information derived from context and the auditory signal as it related to comprehension of specific words in narratives. Contextual influences were manipulated by varying the degree to which the narratives predicted the target words. The auditory influences were manipulated by varying the amount of auditory signal available, either all of the target word or only the initial sound sequence. The results indicated that aphasic subjects use information from both sources but that the contextual information, in its strong form, may take precedence over the auditory information.

Contextual influences during comprehension in aphasia

Abstract Comprehension is the process of deriving meaning. It is often accomplished by integrating information fiom a variety of sources. The purpose of this paper is to review our research programme at Kent State University that has studied how aphasic patients use information from different sources during comprehension.

Word fluency performance on common categories by subjects with closed head injuries

Abstract Previous research on word fluency performance in subjects with closed head injuries has used ad hoc categories such as listing words that begin with particular letters. The nature of this category type may have contributed to the poor performance of these subjects. The present study used common categories, such as fruits and furniture, which are more semantically coherent to assess word fluency performance. In addition to tallying the number of examples retrieved, the nature of the examples was examined in terms of their typicality ratings. The results indicated that the subjects with closed head injuries retrieved significantly fewer examples than did non-brain-damaged subjects. This suggests that their retrieval problems exist independent of the type of category used. Despite the difficulty in retrieving sufficient numbers of category examples, those retrieved were similar to the examples recalled by non-brain-damaged subjects in terms of typicality ratings. This suggests that closed head-injur...

Influence of prior pictorial context on sentence comprehension in older versus younger aphasic subjects

Abstract Deficits in language comprehension have been observed in older individuals, particularly affecting comprehension of complex syntactic constructs such as passive sentences. Aphasic adults display a qualitatively similar pattern, with passive constructions being more difficult to comprehend than active constructs. Various types of context have been found to influence auditory comprehension in aphasia, including the comprehension of passive constructions. In particular, visual stimulation has been observed to facilitate the comprehension of complex spoken messages for many aphasic adults. However, it is unclear whether presenting visual stimuli prior to auditory stimuli is more facilitative than initially presenting auditory stimuli. Furthermore, in light of reported age-related declines in comprehension of passive constructions, it is unknown whether age affects the influence of visual stimulation and, if so, when these effects are more facilatory. In this investigation the influence of pictorial s...