Objectives: Magnetic Resonance Imaging (MRI) has been used to assist the diagnosis of Alzheimer's Disease (AD) in adults with Down's syndrome (DS). However, the interpretation of the scans is difficult and clinical usefulness is uncertain. We aimed to summarise the current knowledge of MRI studies in adults with Down's syndrome with and without dementia and to discuss its implications for clinical practice.
Method: We identified MRI studies in DS by a computerised literature search with Medline, Embase, and Psychlit from 1986 to 2001. We examined the references of identified articles and hand searched relevant journals. Structural MRI studies were selected as this type of imaging is most frequently used in clinical practice.
Results: We included eight volumetric studies in adults with DS. Four of these included adults with DS and dementia. Overall, the size of brain structures such as cerebellum, hippocampus and cortex of adults with DS without dementia was significantly smaller than in normal controls. The basal ganglia were similar in size, and ventricles were enlarged. Furthermore, the size of brain structures in adults with DS and dementia was significantly different than in DS without dementia. In particular, ventricular and hippocampal volumes were affected.
Conclusions: The change in brain structure associated with dementia can be detected on MRI of adults with DS. However, these may be difficult to interpret given the extent to which brain appearance in DS differs from that in the general population. Implications for clinical practice and future research directions are discussed.