Effects of speaking upon the rate and variability of concurrent finger tapping in children

Tapping rate and variability were measured as 73 normal, right-handed children in Grades 1–4 engaged in speeded unimanual finger tapping with and without concurrent recitation. Speaking reduced the rate of tapping and increased its variability to a greater extent in younger children than in older children. Developmental changes in variability but not rate were attributable to a greater number of lengthy (>500 ms) pauses in the tapping of younger children. Speaking slowed the right hand more than the left, and the degree of this asymmetry was constant across grade levels. The right-hand effect for tapping rate was not attributable to lengthy pauses. In contrast, asymmetric increases in tapping variability occurred only among children in Grade 1 and only when lengthy pauses were included in the data. The results implicate three mechanisms of intertask interference: one involving capacity limitations, a second involving cross-talk between motor control mechanisms for speech and finger movement, respectively, and a third factor involving occasional diversion of attention from tapping to speaking. These mechanisms are discussed in relation to developmental changes in mental capacity.     

Subcortical functions in language: A working model

The current paper explains a model of subcortical language functions that focuses on dynamic interactions between the cortex, the thalamus, and the basal ganglia in the production of spoken language. The model was derived from (a) studies of subcortical lesions and language, (b) studies of subcortical stimulation and language, (c) knowledge regarding neural pathways between various cortical and subcortical structures, and (d) indications that preverbal monitoring of language occurs. In the current model, the thalamus plays roles in cortical arousal and activation and in preverbal semantic monitoring. The basal ganglia function to regulate the degree of excitation conveyed from the thalamus to the cortex and to time the release of formulated language for motor programming. Consistency with classical syndromes of aphasia and potential applications to other areas in the neurosciences are discussed. The current theory, unlike previous formulations, is specific enough that testable hypotheses can be derived.     

Optic aphasia, optic apraxia, and loss of dreaming

A 47-year-old man with a left temporo-occipital infarct in the area of the posterior cerebral artery is presented. The neuropsychological examination did not reveal aphasia or gross mental deficits. The patient presented with alexia without agraphia, color agnosia, but few visual perceptual deficits. The main impairment was in confrontation naming; he was incapable of naming objects and pictures, not from lack of recognition (excluding visual agnosia) but from lack of access to the appropriate word (optic aphasia). The patient also exhibited a deficit in the evocation of gesture from the visual presentation of an object (optic apraxia) and a difficulty in "conjuring up" visual images of objects (impaired visual imagery) and loss of dreams. The fundamental deficit of this patient is tentatively explained in terms of visuoverbal and visuogestural disconnection and a deficit of mental imagery.     

Subcortical aphasia with deep dyslexia: A case study of a Japanese patient

The reading performance of a Japanese Broca-type aphasic patient on a single-word reading test was investigated. The result indicated that the subject fits the symptom complex of deep dyslexia in more than one aspect. Unique characteristics of this subject included (1) the isolated subcortical site of the lesion, which apparently produced deep dyslexia, and (2) double dissociations between kanji and kana processing and between oral reading and reading comprehension. The performance of this subject was compared with that of another Japanese deep dyslexic subject in S. Sasanuma (1980, In M. Coltheart, K. Patterson, & J. C. Marshall (Eds.), Deep dyslexia, London: Routledge & Kegan Paul). A theoretical implication was attempted based on a dual coding process scheme by S. Sasanuma and O. Fujimura (1978, Cortex, 7, 1-18).     

Comprehension of directly and indirectly stated main ideas and details in discourse by brain-damaged and non-brain-damaged listeners

Aphasic, right-hemisphere-damaged, and non-brain-damaged subjects heard short narrative paragraphs. Each paragraph contained four main ideas and one or more details related to each main idea. After each paragraph was presented, subjects' comprehension and retention of main ideas and details from the paragraph were tested. Some of the test items directly restated information from paragraphs and others paraphrased information from paragraphs. All groups of subjects remembered main ideas better than they remembered details, and no group of subjects was significantly affected by whether test items directly or indirectly stated information from paragraphs. Disfluent aphasic and right-hemisphere-damaged subjects' overall paragraphs comprehension scores were not significantly poorer than those of non-brain-damaged subjects. Fluent and mixed aphasic subjects' overall paragraph comprehension scores were significantly worse than those of non-brain-damaged and right-hemisphere-damaged subjects. Token Test and Boston Diagnostic Aphasia Examination auditory comprehension scores did not predict aphasic subjects' paragraph comprehension scores. right-hemisphere-damaged subjects' overall paragraph comprehension scores were not significantly those of non-brain-damaged and right-hemisphere-damaged subjects. Token Test and Boston Diagnostic Aphasia Examination auditory comprehension scores did not predict aphasic subjects' paragraph comprehension scores.     

The processing of the sounds and meanings of ongoing speech by aphasic subjects

The ability of aphasic subjects to process the sounds and meanings of ongoing speech was tested. Subjects, 10 aphasic and 20 control, heard test sentences which contained one member of phonemically similar word pairs in one of three semantic contexts: congruent, neutral, and noncongruent. Immediately after hearing a sentence, subjects were to indicate which member of the word pair had been in the sentence. All subject groups had similar overall patterns of response to the different semantic contexts. The division of aphasic subjects into groups of high and low comprehenders revealed response differences. High comprehending aphasic subjects, like control subjects, demonstrated interactive processing of the sounds and meaning of speech while low comprehending aphasic subjects did not.     

Comprehension of main ideas and details in coherent and noncoherent discourse by aphasic and nonaphasic listeners

Aphasic and nonaphasic listeners' comprehension of main ideas and details within coherent and noncoherent narrative discourse was examined. Coherent paragraphs contained one topic to which all sentences in the paragraph related. Noncoherent paragraphs contained a change in topic with every third or fourth sentence. Each paragraph contained four main ideas and one or more details that related to each main idea. Listeners' responses to yes/no questions following each paragraph yielded the following results: (1) Nonaphasic listeners comprehended the paragraphs better than aphasic listeners. (2) Both aphasic and nonaphasic listeners comprehended main ideas better than they comprehended details. (3) Coherence did not affect comprehension of main ideas for either group. (4) Coherence did not affect comprehension of details by nonaphasic subjects. (5) Coherence affected comprehension of details by aphasic subjects, and their comprehension of details in coherent paragraphs was worse than their comprehension of details in noncoherent paragraphs. There was no significant correlation between Token Test scores and measures of paragraph comprehension.