Detecting bilateral abnormalities with voxel-based morphometry

In this article we describe a new method, using SPM99, that searches explic itly for bilateral structural abnormalities. Children with bilateral pathol ogy have a poorer prognosis than children with unilateral damage. After bra in injury or disease in childhood, it is thought that rescue of function is only possible if the neuronal substrates of that function are preserved an d operational in at least one hemisphere [Vargha-Khadem and Mishkin, 1997]. If this is the case, the detection of bilateral abnormalities would greatl y facilitate more accurate prognosis in children with brain injury or devel opmental disorders. We have therefore developed a technique to detect bilat eral abnormalities that uses conjunction analysis with voxel based morphome try. It is illustrated using a group of patients with bilateral hypoxic-isc haemic damage to the hippocampus. The approach is shown to have enhanced sp ecificity and sensitivity relative to conventional unilateral characterisat ions. Hum. Brain Mapping 11:223-232, 2000. (C) 2000 Wiley-Liss, Inc.