Turner's syndrome: further demonstration of the presence of specific cognitional deficiencies.

Previous neuropsychological studies of patients diagnosed clinically and cytogenetically as Turner's syndrome have indicated, on the basis of the Wechsler Intelligence Scales and the Benton Visual Retention Test, that these patients possess a specific cognitive defect in space-form perception (Shaffer, I960; Money, I963). The Wechsler test has also shown that a relative difficulty with numbers, a form of dyscalculia, is associated with the syndrome (Money, I964). These deficiencies do not appear in every case, however, and in this sense they parallel the physical stigmata of the syndrome which, as described by Wilkins (I965), are widely variable. According to the findings mentioned above, the Wechsler performance IQs in Turner's syndrome averaged approximately 20 points lower than the verbal IQs. Furthermore, application of Cohen's (I957; I959) method of factor analysis of the subtest scores showed that the calculation factor (also defined as freedom from distractibility) and the factor of perceptual organization were significantly lower than the verbal comprehension factor. In order to confirm these results, as well as to look for possible additional neurocognitional deficiencies, a group of Turner's syndrome patients has now been tested with the Science Research Associates (SRA) Primary Mental Abilities test (I958). This test, applicable for ages ii to 17 +, is specifically designed to measure separate factors of mental ability; namely, verbal-meaning, space, reasoning, number, and word-fluency. There are percentile scores for each factor and an IQ estimate can be obtained from the verbal-meaning and reasoning factor scores. The SRA test was given individually to i6 patients with an unequivocal diagnosis of Turner's syndrome, who met sample selection criteria designed to avoid intentional bias. All i6 had been originally referred from the Johns Hopkins Hospital Pediatric Endocrine Clinic by Dr. Lawson Wilkins and, more recently, by Dr. Robert M. Blizzard. The diagnosis of Turner's syndrome had been made clinically from the physical stigmata, including, among others, dwarfed stature, webbed neck, and pubertal failure, and was confirmed by buccal smear or chromosome count. Of the i6 patients in the sample, 14 were chromatin-negative or XO, and 2 were chromatin-positive XO/XX mosaics. The age range was from II tO 24 years, the mean age being i5j years. The mean Wechsler IQs for the sample were verbal II2, performance 87.4, and full scale IOI, the respective ranges being I34 to 86, I IO to 65, and I I9 to 80. The mean SRA estimated IQ and IQ range conform fairly closely to the Wechsler findings (see Table) The Table also shows the SRA subtest results. The median and range scores (columns a and b) provide an indication of the group performance on each subtest. Columns c and d indicate the distribution of the percentile scores according to the number falling above the 75th and below the 25th percentiles, respectively. The group was also divided for each subtest into those whose scores fell at the 50th percentile or below, and those at the 5Ist percentile or above (column e). The observed frequency of scores in the two subgroups was compared with the expected (5o/5o) frequency and subjected to a x2 test. The results of this comparison, expressed as the probability that the observed distribution is within normal limits, are shown in column f. The Primary Mental Abilities test results corroborate the earlier observations from the Wechsler test. The verbal-meaning scores approximate a normal distribution. The reasoning scores, though generally lower, are still within nornal limits.