Voice onset time in aphasia: Thai II. Production

The aim of this study was to investigate voice onset time (VOT) production in homorganic word-initial stops in Thai in order to explore the nature of speech production deficits across clinical varieties of aphasia. Thai exhibits a three-category distinction in bilabial (/b,p,ph/) and alveolar (/d,t,t,h/) stops, and a two-category distinction in velar (/k,kh/) stops. Subjects included three Broca asphasics, one transcortical motor asphasic, two global asphasics, one conduction aphasic, one Wernicke aphasic, one nonaphasic dysarthric patient, one right-brain-damaged patient, and five normal controls. Test stimuli consisted of eight monosyllabic real words. The results of VOT measurements indicated that Broca and global asphasics exhibited a more severe production disorder than Wernicke, conduction, or transcortical motor asphasics. The right-brain-damaged patient showed no impairment in VOT production. Comparisons are drawn to earlier studies of VOT production in aphasia in two-category languages. Issues concerning the underlying basis of the production deficit for nonfluent aphasics, fluent aphasics, and nonaphasic dysarthrics as well as the relation between perception and production of VOT are discussed.     

Comprehending homographs in aphasia

This study assessed 13 aphasic subjects' knowledge of the multiple meanings of homographs. The results indicated that the various meanings were less available to aphasic subjects than to normal subjects. In addition, specific meanings became less available as they became less typical although the number of meanings associated with a homograph did not influence performance. Aphasia type also did not influence performance. Performance on the experimental test was significantly correlated with auditory comprehension level and picture naming ability. The results were related to recent findings on semantic organization in aphasia.     

Comments on Hughes and Sussman''s time-sharing study of cerebral laterality in language-disordered and normal children

M. Hughes and H. M. Sussman (1983, Brain and Language, 19, 48-64) suggest that the time-sharing paradigm "does not serve as an adequate behavioral index for language lateralization in children." The merits of this conclusion are considered and general interpretative issues regarding manual interference in dual-task/time-sharing studies are discussed.     

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.     

Sensitivity to lexical denotation and connotation in brain-damaged patients: A double dissociation?

Sets of words can be grouped in terms of their denotation (cold and warm both refer literally to temperature) or in terms of their connotation (cold and warm connote remoteness and intimacy, respectively). To assess whether these two facets of meaning are dissociable, unilaterally left- and right-hemisphere-damaged patients were presented with word triads and asked to group together the two words that were closest in meaning. Right-hemisphere-damaged patients showed a preserved sensitivity to denotation, and a selective insensitivity to connotative facets of meanings. In contrast, left-hemisphere-damaged patients exhibited a preserved sensitivity to connotation as well as a selective insensitivity to denotative aspects of meanings. Inasmuch as normal control subjects displayed a flexible sensitivity to both denotative and connotative aspects of meaning, the results suggest that unilateral brain damage selectively curtails use of one or the other major aspect of word meaning.     

Possible effects of forced report order on tachistoscopic recognition of bilaterally presented stimuli: A response to Young and Ellis

Comparing visual field asymmetries for bilaterally presented words and corresponding line drawings, we found an RVF advantage for words and no visual field asymmetry for line drawings. We suggested that the RVF advantage previously obtained by Young, Bion, and Ellis (Brain and Language, 11, 54–65, 1980) for bilaterally presented line drawings may have resulted from a forced order of report procedure, noting that the RVF advantage was greater on trials on which subjects were forced to report in the nonpreferred right-to-left order. Young and Ellis (Brain and Language, 20, 166–171, 1983) attempt to discredit this claim and maintain their hypothesis that the RVF advantage for line drawings is attributable to better temporary storage of these stimuli by the left than the right hemisphere. In the present article, we present in greater detail our arguments for the effects of forced order of report on the perception of bilaterally presented stimuli and refute Young and Ellis's ibid. criticisms of this proposal.     

The nature of the phonological disorder in conduction aphasia

Sequences of attempts to name pictured objects were used to examine phonological dysfunction in three diagnostic subgroups of aphasia. A prevalence of "phonologically-oriented sequences" (i.e., those sequences that contained only attempts with a phonological resemblance to the target word) was found to be a diagnostic criterion for conduction aphasia. When compared to a group of Broca's (n = 7) and Wernicke's (n = 5) aphasics, all the conduction aphasics (n = 6) produced proportionately more of such phonologically-oriented sequences on a picture naming test. An examination of the phonologically-oriented sequences produced by the conduction aphasics indicates that speech production in conduction aphasia involves dysfunction at an early stage of sound-encoding. The theoretical implications of this view are discussed.     

Language and the young stutterer: A new look at old theories and findings

The major theories and research approaches as to the etiology and development of stuttering are reviewed from a historical perspective. Findings are drawn from different sources indicating that language deficits are an initial contributing factor and a continuing component of this disorder. Those subsets of children which constitute high-risk groups are identified. It is suggested that researchers begin investigating the underlying organic bases of stuttering and its relationship to stages of language development. Finally, clinicians are encouraged to employ a therapy program that is concerned with all areas of language, rather than emphasizing treating only the symptoms of stuttering behavior.     

Speech comprehension after unilateral injection of sodium amytal

A unilateral cerebral dominance model predicts that speech comprehension will be disrupted after injection of sodium amytal into one hemisphere but not after the other. This model was supported when an auditory receptive task involving relatively nonredundant stimuli similar to that contained in the Token Test (E. DeRenzi & L. Vignolo, 1962, Brain, 85, 665–687) was administered to 17 epileptic patients undergoing bilateral amytal injections.     

Measurement of adult performance on Piaget's water horizontality task

Three versions of Piaget's water-level-horizontality task (multiple choice, drawing, and apparatus tests) were administered to 121 female and 74 male adult volunteers. Sex differences and container orientation effects were replicated. Men were more accurate than women and horizontal and vertical container orientations evoked more accurate responses than oblique orientation. Reliability estimates ranged from .78 to .97 and correlations among the measures ranged from .78 to .88. The relative merits of alternative water-level testing and scoring methods and the orientation and type of stimuli to be used are discussed.