Lip EMG activity during vowel production in apraxia of speech: phrase context and word length effects.

This investigation examined the timing relationships of EMG activity underlying vowel production in 2 normal individuals and in 2 individuals with marked-to-severe apraxia of speech of approximately two-and-one-half years duration. The timing of lip muscle activity was investigated in monosyllabic words embedded in phrases and in syllable word stems as a function of changes in word length. Specifically, the onset and offset of EMG activity of lip muscles used for production of /u/ in the monosyllables and word stems were examined. The results revealed that the relative amounts of time devoted to onset and offset of EMG activity for lip rounding are disorganized in apraxia of speech. Word length appeared to affect the timing of the onset of muscle activity for both the normal speakers and the speakers with apraxia of speech. Word length also influenced the offset of muscle activity, but its effect was less systematic for the speakers with apraxia of speech. The findings suggest that termination of EMG activity may be at least as disturbed as the initiation of EMG activity in apraxia of speech.

Access and organization of goal-derived categories after traumatic brain injury.

This study examined the access and organization of goal-derived categories in semantic memory with a group of chronic traumatic brain injured TBI adults and a group of age and gender-matched neurologically-intact controls. Goal-derived categories are developed by individuals for use in specialized contexts to achieve a goal, such as 'things to take on a camping trip.' Categories were presented to subjects in two task contexts: category verification and exemplar generation. Overall, the TBI subjects were able to accurately identify and organize category exemplars within particular categories. Interestingly, the TBI subjects produced significantly more total responses than the neurologically-intact subjects on exemplar generation; however, a high percentage of their responses (one-third) were inaccurate, consisting of out-of-set responses and repetitions. These findings suggest that difficulties in retrieval may exist in the presence of relatively intact access and organization of goal-derived category structure. The results are discussed relative to deficits in the executive control of verifying goal-directed behaviour and incomplete category representation.

Gender differences in laterality patterns for speaking and singing.

This study examined behaviors reflecting cerebral organization of speaking and singing in normal college students. The investigation focused on whether differences existed in the laterality patterns of two singing tasks and one speaking task in males and females. Performance was measured on a verbal/manual time-sharing paradigm, coupling finger tapping with three vocal tasks (speaking, singing a rote song, singing up and down a diatonic five note scale). Females exhibited less variation than males in mean tapping rates and laterality scores across all three vocal tasks, thus indicating that gender most likely influences lateralization of vocal tasks. Bilateral integration was indicated for both males and females during singing up/down the aforementioned scale. These findings suggest differential involvement of both hemispheres in processing musical functions.

Treatment of Wernicke's aphasia with jargon: a case study.

This case study concerns an adult with Wernicke's aphasia characterized by neologistic jargon and a severe auditory comprehension deficit. No communicative or linguistic improvements had been observed after eight months poststroke. Up until this time, therapeutic intervention was aimed at managing the patient's rambling communicative style and improving auditory comprehension skills. A therapeutic regimen was introduced that focused on visual/written information and included a hierarchy of visual word and sentence comprehension tasks. All auditory/verbal stimulus presentation was eliminated. After two months on the program, improvement was noted in naming abilities and general ability to communicate in conversation, including a reduction of neologistic jargon and an increase in semantic jargon. No improvement was noted in auditory comprehension. The visual program may have facilitated the patient's general attentional set, thereby possibly contributing to her improvement in communicative style and sensitivity to conversational interactions with others.

Narrative comprehension in adults with right and left hemisphere brain-damage: theme organization.

The effects of delayed presentation of a central theme on the comprehension and interpretation of narratives were investigated in adults with right and left hemisphere brain-damage and normal individuals. The performance of subgroups of the subjects with right and left hemisphere brain-damage also was examined. Right hemisphere brain-damaged groups with anterior and posterior lesions were significantly less accurate and identified significantly fewer central themes when central theme presentation was delayed until the end of a narrative than when the theme was presented at the beginning. Subjects with anterior right hemisphere brain-damage produced significantly more embellishments and confabulations than subjects with posterior damage and non-brain-damaged controls, regardless of theme condition. The performance of non-brain-damaged subjects and subjects with fluent and nonfluent aphasia was unaffected by the organization of the central theme in the narratives.

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.