Development of lateral asymmetry in the perception of sequentially touched fingers

In order to investigate lateral asymmetry in tactile perception, two or four fingers of normal primary school children were touched sequentially. Stimulation was either unimanual or bimanual and either verbal or nonverbal responses were required. Right hand advantage was demonstrated subsequent to uni- and bimanual stimulation in both the verbal and nonverbal response conditions. Neither an age nor a sex effect on laterality was found. Right hand advantage was affected by direction of stimulation in the bimanual condition. Left hemispheric dominance was argued to be related to the temporal nature of the tasks.     

On various causes of improper solutions in maximum likelihood factor analysis

In the applications of maximum likelihood factor analysis the occurrence of boundary minima instead of proper minima is no exception at all. In the past the causes of such improper solutions could not be detected. This was impossible because the matrices containing the parameters of the factor analysis model were kept positive definite. By dropping these constraints, it becomes possible to distinguish between the different causes of improper solutions. In this paper some of the most important causes are discussed and illustrated by means of artificial and empirical data.The author is indebted to H. J. Prins for stimulating and encouraging discussions.     

Treatment of obsessive-compulsive patients: The contribution of self-instructional training to the effectiveness of exposure

Fifteen obsessive-compulsive patients were given treatment consisting of ten sessions of gradual exposure in vivo. For half of the patients gradual exposure in vivo was preceded by self-instructional training.Treatment resulted in significant improvement on anxiety and avoidance scales, Leyton Obsessional Inventory, Self-rating Depression Scale and on ratings for anxious mood and depression. Neither the post-test nor the follow-ups 1 month and 6 months later indicated a difference between the effects of the two conditions. Self-instructional training did not enhance the effectiveness of gradual exposure in vivo.     

Central deafness and subcortical motor aphasia

Clinical and autopsy studies were made on a right-handed man who had central deafness and subcortical motor aphasia, and the literature on central deafness and on subcortical motor aphasia was analyzed. Central deafness is due to bilateral destruction of the primary auditory cortex. It is sometimes difficult to distinguish from word deafness and from auditory agnosia, which are due to pathology in other parts of the temporal lobes. There is almost always some preserved hearing in central deafness, possibly from some auditory pathway other than the classical pathway. In this patient the subcortical motor aphasia was due to bilateral destruction of the motor cortex for the mouth and throat. In some other cases subcortical motor aphasia was due to the same pathology that usually causes Broca's aphasia; in these cases the unexpected preservation of writing was perhaps related to some difference in how language functions were organized in the brain.     

Production deficits in aphasia: A voice-onset time analysis

An experimental study was conducted to examine phonetic and phonemic deficits in the speech production of aphasics. Subjects included four Broca's aphasics, four Conduction aphasics, five Wernicke's aphasics, one nonaphasic dysarthric patient, and four normal controls. The subjects read a list of words containing word-initial stop consonants which were subsequently measured acoustically for voice-onset time. The results showed that Broca's aphasics exhibit a more severe production disorder than Conduction aphasics who in turn exhibit a more severe disorder than Wernicke's aphasics, in accord with clinical observations. In addition, although Broca's aphasics produced both phonetic and phonemic errors, the results showed that they have a pervasive phonetic disorder which affects their correct target productions as well as the total number of phonetic errors produced. This deficit however seems to be a speech deficit rather than a low-level motor control problem. In contrast, the Wernicke's aphasics show a deficit characterized by isolated phonemic mistargeting errors. Finally, the pattern of productions for the Conduction aphasics indicates that some patients show a predominantly phonetic disorder similar to the Broca's aphasics and others show predominantly a phonemic disorder similar to the Wernicke's aphasics.     

TEACHING THE HANDICAPPED TO EAT IN PUBLIC PLACES: ACQUISITION,GENERALIZATION AND MAINTENANCE OF RESTAURANT SKILLS

This study examined classroom-based instruction in restauranting skills for handicapped persons. Three male students were taught each of four skill components in sequential order: locating, ordering, paying, and eating and exiting. Training was implemented in a multiple baseline design across subjects and consisted of modeling and role playing in conjunction with photo slide sequences and a simulated ordering counter. The use of a menu containing general item classes and a finger matching procedure for identifying errors in the delivery of change greatly reduced the reading and math skills necessary to enter and complete the program. Periodic probes were conducted in a McDonald's restaurant prior to, during, and up to one-year following the termination of training. In addition, two probes (overt and covert observation) were conducted in a Burger King restaurant to assess further generalization to a location different from the one depicted throughout training. Results showed that students' performance on restaurant probes improved as a result of training, generalized to novel settings, maintained over an extended period of time, and was comparable to that of a normative sample of nonretarded persons.     

Foveal diplopia thresholds and fixation disparities

Comparison of the magnitude and intrinsic spread of foveal diplopia thresholds with the accuracy of ocular alignment as determined with a subjective alignment method shows that: the accuracy of alignment in the vertical direction (within 1–2 min) is remarkably good and much better than in the horizontal direction; the largest disparities occurring due to restricted alignment accuracy are usually substantially smaller than the foveal diplopia thresholds; interindividual variability in the magnitude of foveal diplopia thresholds is not due only to interindividual variability in the alignment accuracy; and the spread of foveal diplopia thresholds exceeds the spread of ocular alignment, which implies that the noise in the foveal disparity domain is not only due to the restricted alignment accuracy but also to sensory processes. Finally, the data confirm that, unlike the case with diplopia thresholds, the spread of stereoscopic thresholds is not affected by the restricted alignment accuracy.