Can spatial deficits in Turner's syndrome be explained by focal CNS dysfunction or atypical speech lateralization?

The spatial impairments of Turner's Syndrome were examined by administering perceptual, constructional, and nonverbal memory tasks to 11 probands and 22 controls matched for phenotypic sex, age, education, and hand preference. Visual imperception was more pronounced than constructional apraxia. Deficits in attention span were present, but they were not restricted to the visual modality or to nonverbal stimuli. Further neuropsychological tests of focal brain dysfunction and speech lateralization revealed slightly increased somatosensory thresholds of the left palm, attenuated manual asymmetry, and diminished right-visual-field superiority on letter identification. Different measures of spatial ability correlated with the somatosensory scores, the manual scores, and the speech representation scores, but the latter three variables showed no significant interrelationships. It is concluded that a unitary explanation in terms of focal CNS dysfunction or atypical speech representation can not account for the pattern of neuropsychological deficits seen in Turner's Syndrome.