Articulatory and phonological aspects of consonant substitutions in apraxia of speech.

The articulatory and distinctive features in 825 consonant substitutions produced by nine subjects with apraxia of speech were analyzed. The articulatory and distinctive features of the target consonants were retained beyond chance levels. The substitution patterns observed were very systematic in that more substitutions were made in the initial word position and stops, alveolars, and voiced consonants were used most often as substitutes for target consonants. The retention and usage of the features in the substitutions were closely related to the phonological markedness of the features, Most of the markedness changes were from marked-to-unmarked. The relationships between distinctive features and their markedness suggest that apraxia of speech is primarily a phonological disorder that is manifested in articulatoriy changes. It appears therefore that speakers with apraxia of speech systematically reduce linguistic complexity and simplify the production of consonants. In addition, the substitutions made in apraxia of speech are similar to those made by children.

The effects of single versus combined cue presentations on picture naming by aphasic adults.

Research has demonstrated that the presentation of auditory and visual cues is an effective clinical procedure for improving picture naming of nonfluent aphasic speakers. The effect of combined cue presentation, however, has not been clearly demonstrated. The present study investigated the effect of single and multiple cueing techniques used with nonfluent (Broca's) aphasic patients. The subjects were divided into a minimum or maximum error group based on their performance on a picture-naming task. Printed words (in either cursive or manuscript style), initial syllables, and sentence completion cues were presented independently and in combination. Discussion is directed toward the potential clinical application of multiple cueing techniques.

The effectiveness of simultaneous cues on naming disturbance in aphasia.

The effects of increased information redundancy on word retrieval in aphasic patients was investigated in this study. Protocols involved combining five types of cues commonly utilized in aphasia management into eight pairs, each of which could be presented simultaneously. The resulting cue combinations were presented to 16 anterior lesion aphasic subjects who manifested mild to severe word-finding difficulty. All of the combinations were effective in facilitating picture-naming performance, with the severe group demonstrating the most dramatic improvement when simultaneous prompts were utilized. A cueing hierarchy incorporating increased stimulus redundancy is supported.

Dichotic word-perception of aphasic and normal subjects.

The present investigation examined the role of the right cerebral hemisphere in linguistic perception following a left cerebral insult which had resulted in aphasia. Auditory dichotic procedures were utilized to investigate the ear-preferences of 30 aphasic Ss, grouped relative to the amount of time since the onset of left cerebral insult, and a group of 10 normal control Ss. An oral-response task and a pointing-response task were given. Statistical analyses showed a significant left-ear preference for aphasic Ss who were more than 6 mo. post-cerebral insult; however, Ss less than 6 mo. post-cerebral insult did not demonstrate a significant ear-preference under auditory dichotic stimulation. In contrast, a significant right-ear preference was noted for the normal controls. Significant differences were not shown for the aphasic or control groups on the oral and pointing tasks.

Dichotic ear preference in aphasia.

A dichotic listening test, composed at 30 CVC-word pairs, was administered to 20 adults with aphasia and 20 normal adults. The subjects with aphasia were selected for inclusion in one of four experimental groups which differed according to intitial severity of aphasia and time post onset. All experimental subjects were given a diagnostic language test within the first four weeks following aphasia onset and again at the time of dichotic testing. Difference scores provided a quantitative estimate of language improvement. Data analysis revealed a strong left-ear preference (-0.363) for the experimental subjects which differed significantly from a right-ear preference (+0.290) obtained from the normal control subjects. Further, initial severity of aphasia was found to be a significant variable, capable of influencing the magnitude of ear preference. Multiple regression and partial correlational methods revealed significant, positive relationships between the magnitude of ear preference and initial severity of aphasia and between the former and the magnitude of language improvement. Time post aphasia onset was not shown to be a significant variable. The theoretical and potential clinical relevance of the results are discussed.