A correlational study of stutterers' adaptation and voice initiation times

The purpose of this study was to determine the strength of the relationship, if any, between stutterers' amount of improvement in controlling phonation (voice initiation time) and their amount of improvement in stuttering during adaptation.Thirteen adult stutterers were required to participate in an adaptation task and a voice initiation time (VIT) task. The major finding was a weak, positive correlation between subjects' adaptation and their VIT difference scores. The correlation obtained, though weak, was interpreted to be informative; namely that while there is quite probably a laryngeal component in stuttering, it does not stand alone. It seems likely that the complexities of stuttering will not be fully understood until experiments include a number of potential or known dimensions of the disorder.     

Prosopagnosia and visual object agnosia: A behavioral study

A left-handed woman developed visual object agnosia, prosopagnosia, and visual disorientation after resection of the right occipital lobe. Color agnosia and alexia were absent. When asked to identify objects presented visually, the patient's errors represented visually related objects (underspecifications) or perseverations. Identification was facilitated when she observed the object being used in a natural way. Identification was impaired by surrounding the object with unrelated objects, decreasing the background illumination, decreasing the duration of exposure of the object to the patient, and probably also by decreasing the visual angle subtended by the object. In addition, there were disturbances of visualization (i.e., imaging in the absence of a visual stimulus) that paralleled the perceptual difficulties. We conclude that: (1) A deficit in visual perception, characterized by insufficient feature analysis of visual stimuli, was the basis of the visual agnosia in this case. (2) The visual agnosia could not be explained by (a) a vision-language disconnection syndrome, (b) decay of visual memory traces, or (c) deficiencies in the visual fields (pathologic Funktionswandel). (3) The ability to visualize (visual imagery) probably utilizes some of the same neural pathways used in perception. (4) The results in this case probably can be generalized to some but not all cases of visual agnosia; in particular, the deficit in most previously reported patients with prosopagnosia is similar to that of our case. However, agnosic alexia and color agnosia usually have a different neuropsychological basis.