Cerebral visual impairment in cerebral palsy: relation to structural abnormalities of the cerebrum.

In patients with cerebral palsy (CP), cerebral visual impairment (CVI) is frequently found in addition to ophthalmological disorders. Lesions in the visual areas are found in CT scans of CP patients with CVI. The aim of the present study was to determine the prevalence of these specific findings in CP patients with CVI. CT scans of 49 cerebral palsy patients were studied; CVI was diagnosed in 36 patients; in 13 patients, visual acuity was normal. In 8 patients, comparison with an MRI scan was possible (6 with CVI, 2 with normal acuity). The CT scans were scored according to the criteria used by Van Nieuwenhuizen (1987): normal, abnormalities of the white matter adjacent to the posterior horns of the lateral ventricles, abnormalities of the white matter located under the visual cortex, abnormalities of the visual cortex and abnormalities elsewhere. Abnormalities in the visual areas were found in 15% of the normal acuity group and in 53% of the CVI group. In 17 of the 19 CVI patients with abnormalities in the visual areas, the lesions were located in the white matter surrounding the posterior horns (89%). MRI imaging revealed the same abnormalities as the CT scans in 6 patients, but in one patient the abnormality was seen in more detail and in one patient the lesion in the occipital area was seen only on MRI. MRI examination seems to detect at least as many, but in some cases even more specific lesions in CVI patients compared to CT scanning, but the numbers were too small to allow any definitive conclusions to be drawn.