Magnetic resonance imaging of brain anatomy in severe developmental dyslexia.

The brain anatomy of ten men (aged 18 to 28 years) with persistent, severe developmental dyslexia was examined with magnetic resonance imaging to explore the possibility of visualizing pathology not seen in previous computed tomographic scan studies. Nine of the ten examinations were clinically normal. One showed a focal finding thought to be incidental to dyslexia. The volume of the temporal lobes was judged to be symmetrical in nine of ten examinations, a finding supportive of previous computed tomographic scan and neuropathologic reports of unusual symmetries of posterior brain regions. Thus, despite its sensitivity, magnetic resonance imaging failed to identify a common focal pathology. The choice of imaging planes (particularly coronal) and lack of bone artifact may, however, prove useful for studying macroscopic asymmetries in dyslexia.