No abstract

Sixty-eight Ss voluntarily restrained head, eye and blitlking movements while lJieu'ing a luminous "lIB" figure in a dark

The association of porencephalic cysts with hydrocephalus was first cited in 1939. Subsequent descriptions of this combination in terms of fixed, nonprogressive neurological problems have been reported. We describe four patients with hydrocephalus who had progressive focal motor deficits secondary to porencephalic diverticulation of the lateral ventricle. Symptoms of increased intracranial pressure were not a consistent finding in all patients. Enlargement of the porencephalic cyst is related to either a generalized increase in intraventricular pressure or to "hydrostatic" forces that may act independently. Computerized axial tomography has provided a noninvasive technique that allows definition of the abnormality and its progression. Neurosurgical intervention has resulted in clinical improvement in all patients studied.

Sixty-eight Ss voluntarily restrained head, eye and blinking movements while viewing a luminous "HB" figure in a darkened room. All Ss were told that voluntary fixation would cause parts of the pattern to disappear; they were to report the parts that remained intact. Half of the Ss reported their disappearances verbally. The other half traced their disappearances on an outline "HB" figure. Results showed that the verbal method significantly favored the reporting of elements from the set H, h, B, b, 1, 11, +. These data suggest that response bias rather than perceptual organization may be responsible for the preponderance of meaningful disappearances noted in previous research.