Clinical significance of isolated mega cisterna magna.
OBJECTIVE
The prevalence and clinical significance of isolated mega cisterna magna in both fetuses and adults is not yet well defined. It is therefore difficult to provide reliable parental counseling in cases of a fetal sonographic diagnosis of this anomaly. The aim of the present study was to, determine the cognitive profile of adults with isolated mega cisterna magna.


METHODS
We reviewed 19,301 consecutive CT/MRI of the brain. Isolated mega cisterna magna was observed in 49 cases. A battery of neuropsychological tests was performed in 18 adults with this anomaly and in 18 controls who had no brain anomaly on CT/MRI.


RESULTS
Subjects with isolated mega cisterna magna had a lower performance on memory tasks [RAVLT saving score (0.8 +/- 0.2 vs. 1.02 +/- 0.2, P = 0.003)] and verbal fluency [phonemic fluency (9.4 +/- 4.5 vs. 13.6 +/- 5.3, P = 0.02), semantic fluency (19.8 +/- 5.8 vs. 24.4 +/- 7.5, P = 0.05)]. They did not differ from controls in regard to the Raven similarity tests indicating that this brain anomaly is not associated with impairment of general cognitive abilities.


CONCLUSIONS
Adults with isolated mega cisterna have an overall normal cognitive functioning but may score inferior to controls on some parameters of memory and verbal fluency. Although application of adult cases to the fetuses is not well established, this information might be of value in parental counseling in cases of a fetus with this anomaly.
Zimmer
Etan Z
EZ
Department of Obstetrics Gynecology, Rambam Medical Center, 31096 Haifa, Israel. e_zimmer@rambam.health.gov.il
Lowenstein
Lior
L
Bronshtein
Moshe
M
Goldsher
Dorith
D
Aharon-Peretz
Judith
J
D000328:Adult; D016022:Case-Control Studies; D002946:Cisterna Magna; D003616:Dandy-Walker Syndrome / Q000000981:diagnostic imaging / Q000473:pathology / Q000523:psychology*; D005260:Female; D005817:Genetic Counseling; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011859:Radiography; D016216:Ultrasonography, Prenatal