Adaptation to Altered Visual-Proprioceptive Input in Normals and Schizophrenics

Adaptation to Prismatic Displacement by Schizophrenics and Normals

“…The results of the present study expand upon, but are also slightly at variance with results reported by Ebner et al (4). Those authors reported that schizophrenics failed to adapt significantly in a visually guided marking task, following exposure to prismatically dis placed images of their own moving hands.…”

“…In the present study the pointing task most nearly corresponds to the test task used by these authors, and like them, we found that the normals showed a mean adaptive shift greater than that of the schizophrenics. How ever, we also find that both groups showed highly significant extents of adaptation on this task, and the amount of difference between them, though approaching significance, was not nearly as great as that reported by Ebner et al (4). While the notion of proprioceptive deficits in schizophrenics is not refuted by our result, certainly some réévaluation of the magnitude of any such deficit is called for.…”

“…(3) reported difficulties by schizophrenics in a task involving visualauditory integration. Finally, in a study focus ing upon visual-proprioceptive integration, Ebner et al (4) showed that schizophrenics failed to show significant adaptation in visually guided marking following short-term exposure to a prismatically displaced view of their own hands. Normal controls did adapt significantly in that same test situation.…”

The Israeli High-Risk Study: Statistical Overview and Discussion

“…Finally, tests of visual-motor coordination in the neurological examination, as well as the mirror-drawing test, indicated deficits in the index group. Many other investigators of schizophrenic patients and their offspring have noted disturbances in areas of perception (Neale 1971; Erlenmeyer-Kimling 1975), attention (Chapman and McGhie 1962; Gamer et al 1977; Rutschmann, Cornblatt, and Erlenmeyer-Kimling 1977), motor function (Hanson, Gottesman, and Heston 1976; Rieder and Nichols 1979), and perceptual-motor integration (Ebner, Brockma, and Ritzler 1971; Fish and Hagin 1973).…”

The neuropsychology of 3-D space.

“…The diminished role of bodily sensory systems in persons with schizophrenia is further reflected in (a) a heightened visual field dependence and other spatial orientation difficulties that point to a disturbance of central vestibular processing (Mirabile, Glueck, & Stroebel, 1976;Ornitz, 1970;J. Q Wells & Caldwell, 1967;Werner, Black, Comes, Larkin, & Steinhauer, 1982), (b) auditory, hallucinations that stem mainly from undetected proprioceptive input (Bick & Kinsbourne, 1987), (c) an impaired use of proprioceptive information in recalibrating perceptualmotor operations during adaptation to altered visual environments (Ebner, Broekema, & Ritzier, 1971), and (d) severely deranged bodily images and bodily experiences (Chapman, Chapman, & Raulin, 1978). Finally, the preoccupation with grandiose themes, alien control, and similar delusional thought tendencies may represent a cognitive analogue of a reality dissociated from internal sensory references.…”