Intelligence quotient in children with meningomyeloceles: a case–control study

Abstract

Meningomyelocele (MMC) is a common central nervous system birth defect. As one of many problems facing patients with MMC, learning disabilities are often overlooked. The aim of this study was to evaluate IQs in a group of children with MMCs and determine if a correlation exists between intelligence level and the presence of an MMC and/or its complications. A case-control study was conducted at the Children's Hospital Medical Center in Tehran, Iran, from December 2004 through December 2005. The patient group included 50 children with MMC from 5 to 12 years of age who were referred to the authors' institution for treatment of complications or for follow up after surgery for MMC closure. The patient group was individually matched for age and sex with a control group of 50 children referred to the hospital for other reasons and who did not have MMC or other neurological abnormalities. The IQs in all children in this study were evaluated using the Ravens Progressive Matrices test. The children in both groups were similar in the socioeconomic status of the family (p = 0.347) and educational status of the father (p = 0.117) and mother (p = 0.439). Patient age at the time of surgery for MMC closure varied from 1 day to 96 months (mean 4.1 months). Only 20% of the patients with MMC could walk with a normal gait. Forty-six percent of the patients had undergone placement of a ventriculoperitoneal shunt, and half of these patients experienced shunt-related complications; 72% of the children in the patient group were completely incontinent for both urine and feces. The IQ results obtained in the patient group ranged from 73 to 134 with a mean (+/- standard deviation) of 96.62 +/- 13.01. In the control group the IQ range was 70 to 128, and the mean was 104.82 +/- 12.30. Compared with the control group there was a statistically significant correlation between having an MMC and having a lower IQ (p < 0.001, paired t-test). Although the average IQ in the patient group was significantly lower than that in the control group, it is important to note that all children in the patient group had an average or above-average IQ. In contrast with the results reported in other studies, earlier repair of the MMC, the presence of a shunt or shunt-related complications, walking difficulty, and the spinal level of the lesion did not correlate significantly with IQs. Therefore, the lower IQ and reduced cognitive levels noted in these patients result from the disease process itself and not from the associated complications.