Abnormal olfactory sulcus depth points to later schizophrenia risk
MedWire News: An abnormal olfactory sulcus depth in early embryonic development may be a biomarker for later risk for developing schizophrenia, the results of a US study indicate.
The fetal risk for schizophrenia increases from the late first through to early second trimester, with several studies indicating that developmental disruption during this period contributes to the development of the condition.
Noting that olfactory sulcus depth is linked to the embryonic development of both the olfactory system and the cerebral cortex, Bruce Turetsky and colleagues from the University of Pennsylvania in Philadelphia used magnetic resonance imaging (MRI) to measure the depth of olfactory and orbital sulcas in 36 schizophrenia patients and 28 mentally healthy controls.
The team reports in the journal Schizophrenia Research that patients had significantly shallower olfactory sulcal depths on the right hemisphere compared with controls, but not on the left hemisphere.
No other clinical or demographic variables were significantly associated with olfactory sulcal depth and, although orbital sulcal depth was not significantly associated with diagnosis or hemisphere, depth became shallower with increasing age.
Interestingly, olfactory and orbital sulcal depths were significantly correlated in healthy controls, with orbital sulcal depth explaining 75% of the variation in olfactory sulcal depth, whereas there was only a weak correlation in patients, with only 23% of olfactory sulcal depth variance explained.
Discussing the shallow olfactory sulcal depth in patients, the team says: “The fact that this anomaly was not seen in the adjacent orbital sulcus, which develops much later in gestation, supports the interpretation that this is an index of aberrant early neurodevelopment rather than a nonspecific correlate of cortical atrophy.”
They add: “Since manual measurements of olfactory sulcal depth can be easily obtained from MRI scans of children and adolescents at risk for schizophrenia, its potential utility as a predictive biomarker in this population warrants further investigation.”
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By Liam Davenport