Smooth pursuit eye movement (SPEM) in patients with multiple complex developmental disorder (MCDD), a subtype of the pervasive developmental disorder

Multiple complex developmental disorder (MCDD) is a well-defined and validated behavioural subtype of pervasive developmental disorder-not otherwise specified (PDD-NOS) and is thought to be associated with a higher risk of developing a schizophrenic spectrum disorder. The question was addressed whether patients with MCDD show the same psychophysiological abnormalities as seen in patients with schizophrenia.Smooth pursuit eye movement (pursuit gain and saccadic parameters) was measured in children with either MCDD (n=18) or autism (n=18), and in age- and IQ-matched controls (n=36), as well as in a group of adult patients with schizophrenia (n=14) and a group of adult controls (n=17).We found the expected effect of lower velocity gain and increased number of saccades in schizophrenic patients. Children with MCDD also showed a lower velocity gain compared to controls children. In contrast, velocity gain was similar in autistic subjects and controls. No differences for velocity gain were found in a direct comparison between MCDD and autism. Saccadic parameters were not significantly different from controls in either MCDD or autistic subjects.Children with MCDD, like schizophrenic adults, show a reduced velocity gain, which could indicate that schizophrenia spectrum disorders and MCDD share (at least to some degree) a common neurobiological background.