Production of graphic symbol sentences by individuals with aphasia: efficacy of a computer-based augmentative and alternative communication intervention

The study employed a single-subject multiple baseline design to examine the ability of 9 individuals with severe Broca's aphasia or global aphasia to produce graphic symbol sentences of varying syntactical complexity using a software program that turns a computer into a speech output communication device. The sentences ranged in complexity from simple two-word phrases to those with morphological inflections, transformations, and relative clauses. Overall, results indicated that individuals with aphasia are able to access, manipulate, and combine graphic symbols to produce phrases and sentences of varying degrees of syntactical complexity. The findings are discussed in terms of the clinical and public policy implications.     

A Multitrait–Multisource Confirmatory Factor Analytic Approach to the Construct Validity of ADHD and ODD Rating Scales with Malaysian Children

Confirmatory factor analysis (CFA) was used to model a multitrait by multisource matrix to determine the convergent and discriminant validity of measures of attention-deficit hyperactivity disorder (ADHD)-inattention (IN), ADHD-hyperactivity/impulsivity (HI), and oppositional defiant disorder (ODD) in 917 Malaysian elementary school children. The three trait factors were ADHD-IN, ADHD-HI, and ODD. The two source factors were parents and teachers. Similar to earlier studies with Australian and Brazilian children, the parent and teacher measures failed to show convergent and discriminant validity with Malaysian children. The study outlines the implications of such strong source effects in ADHD-IN, ADHD-HI, and ODD measures for the use of such parent and teacher scales to study the symptom dimensions.     

Visual search for object orientation can be modulated by canonical orientation

The authors studied the influence of canonical orientation on visual search for object orientation. Displays consisted of pictures of animals whose axis of elongation was either vertical or tilted in their canonical orientation. Target orientation could be either congruent or incongruent with the object's canonical orientation. In Experiment 1, vertical canonical targets were detected faster when they were tilted (incongruent) than when they were vertical (congruent). This search asymmetry was reversed for tilted canonical targets. The effect of canonical orientation was partially preserved when objects were high-pass filtered, but it was eliminated when they were low-pass filtered, rendering them as unfamiliar shapes (Experiment 2). The effect of canonical orientation was also eliminated by inverting the objects (Experiment 3) and in a patient with visual agnosia (Experiment 4). These results indicate that orientation search with familiar objects can be modulated by canonical orientation, and they indicate a top-down influence on orientation processing.     

Multiple-object tracking is based on scene, not retinal, coordinates

This study tested whether multiple-object tracking-the ability to visually index objects on the basis of their spatiotemporal history-is scene based or image based. Initial experiments showed equivalent tracking accuracy for objects in 2-D and 3-D motion. Subsequent experiments manipulated the speeds of objects independent of the speed of the scene as a whole. Results showed that tracking accuracy was influenced by object speed but not by scene speed. This held true whether the scene underwent translation, zoom, rotation, or even combinations of all 3 motions. A final series of experiments interfered with observers' ability to see a coherent scene by moving objects at different speeds from one another and by distorting the perception of 3-D space. These reductions in scene coherence led to reduced tracking accuracy, confirming that tracking is accomplished using a scene-based, or allocentric, frame of reference.     

Perception of visual speed while moving

During self-motion, the world normally appears stationary. In part, this may be due to reductions in visual motion signals during self-motion. In 8 experiments, the authors used magnitude estimation to characterize changes in visual speed perception as a result of biomechanical self-motion alone (treadmill walking), physical translation alone (passive transport), and both biomechanical self-motion and physical translation together (walking). Their results show that each factor alone produces subtractive reductions in visual speed but that subtraction is greatest with both factors together, approximating the sum of the 2 separately. The similarity of results for biomechanical and passive self-motion support H. B. Barlow's (1990) inhibition theory of sensory correlation as a mechanism for implementing H. Wallach's (1987) compensation for self-motion.     

Syllable structure and sonority in language inventory and aphasic neologisms

Phonological theories have raised the notion of a universally preferred syllable type which is defined in terms of its sonority structure (e.g., ). Empirical evidence for this notion has been provided by distributional analyses of natural languages and of language acquisition data, and by aphasic speech error analyses. The present study investigates frequency distributions of syllable types in German, which allows for a rather complex syllable structure, and in neologistic utterances of a German speaking jargon aphasic. The findings suggest that the sonority structure of the patient's neologisms is generally in accordance with the notion of theoretically preferred syllables. Moreover, comparative analyses suggest that the predominance of the preferred syllable type is especially pronounced in the aphasic data. On the basis of these findings, the influence of sonority in impaired phonological lexical processing is discussed.     

The processing of the right-sided accent mark in left neglect dyslexia

Italian polysyllabic words with stress falling on the last syllable are written with a diacritic sign on the last vowel. It allows discrimination between two words with the same orthographic segments (e.g., papa [pope], papà [dad]). The effect of the accent mark in left neglect dyslexia has never been investigated. In the current study, six patients with neglect dyslexia were asked to read aloud homographic words and non-words, with or without the accent mark. The presence of the accent improved reading performance of three patients but only with real words. In contrast, two patients ignored the accent mark, even if it relied on the right ipsilesional space. We conclude that the accent mark is computed separately from letter identity and that it can act as an important cue for lexical access.     

Mental representation of prepositional compounds: evidence from Italian agrammatic patients

The processing of Prepositional compounds (typical Neo-latin noun--noun modifications where a head noun is modified by a prepositional phrase, e.g., mulino a vento, windmill) was preliminarily studied with a group of six agrammatic aphasic patients, and, in more detail, with a further agrammatic patient (MB). Omission was the most frequent error type in naming, whereas in the other tasks (repetition, reading, writing, and completion) errors were mostly substitutions of the target preposition. This happened even with fully lexicalized compound forms, i.e., those forms where the linking preposition is syntactically and semantically opaque. These findings are interpreted in terms of a dual-route theory of lexical access to morphologically complex words.     

Paralinguistic processing in children with callosal agenesis: emergence of neurolinguistic deficits

Recent research revealed impaired processing of both nonliteral meaning and affective prosody in adults with agenesis of the corpus callosum (ACC) and normal intelligence. Since normal children have incomplete myelination of the corpus callosum, it was hypothesized that paralanguage deficits in children with ACC would be less apparent relative to their peers. The Familiar and Novel Language Comprehension Test (FANL-C) and Prosody Test were given to 18 children with ACC and normal intelligence and 17 controls matched for age (7-13 years), education, and IQ (83-122). When controlling for age, children with ACC were significantly poorer in comprehension of the precise meaning of both literal and nonliteral items on the FANL-C. Adults with ACC had previously been shown to have difficulty only on nonliteral items. The effect size for nonliteral comprehension in children with ACC was smaller than that seen in adults. There was only a trend for the child ACC group to perform worse on the recognition of affective prosody. Thus, while deficits in paralinguistic processing were apparent, children with ACC were not as clearly different from age peers as adults, and were equally deficient at comprehending literal and nonliteral expressions. The differences in results between adults and children with ACC are thought to reflect incomplete callosal development in normal children, and the importance of the corpus callosum in the early stages of the development of the ability to process literal language.