Brain proton magnetic resonance spectroscopy and brain atrophy in myotonicdystrophy

Objectives: To evaluate by magnetic resonance spectroscopy the age-related cerebral alterations present in myotoplic dystrophy (MD) and to compare the se results with those obtained by magnetic resonance imaging. Design: Twenty-one patients (aged 16-63 years) with MD were compared with 1 6 age-matched healthy control subjects. Results: In magnetic resonance spectroscopy, the mean (+/-SD) ratio of N-ac etylaspartate to creatine and phosphocreatine in the patients with MD (1.09 +/- 0.32) was significantly lower than that in the control subjects (1.93 +/- 0.43) (P < .001). The mean ratio of N-acetylaspartate to choline-contai ning compounds in the patients with MD (1.70 +/- 0.44) was also significant ly lower than that in the control subjects (2.75 +/- 0.53) (P < .001). Thes e changes could be observed already in the younger patients. In magnetic re sonance imaging, the mean brain area was significantly decreased and the me an ventricular space was significantly increased in patients with MD compar ed with the control subjects. Although we have confirmed brain atrophy in p atients with MD in previous reports, a regression analysis indicated that t he brain shrinks progressively with age in patients with this disorder and in control subjects, resulting in overlapping values for younger subjects. Conclusion: Magnetic resonance spectroscopy indicates that the cerebral abn ormalities in patients with MD may be present at an early stage, when the r esults of magnetic resonance imaging studies are still equivocal.