Neuroanatomical correlates of depression in Friedreich's ataxia: a voxel-based morphometry study

Affective disorders have been increasingly recognized in neurodegenerative diseases and often result in poor quality of life. However, the frequency, clinical relevance, and anatomical substrate of depression in Friedreich's ataxia were not yet evaluated. We assessed 22 patients with Friedreich's ataxia for major depression using Beck Depression Inventory and cerebral 3 T MRI scans. We then employed whole-brain voxel-based morphometry analyses on volumetric T1 datasets to compare tissue loss between patients with and without major depression. Patients (36.3 %) fulfilled criteria for major depression (8/22). Mean Beck Depression Inventory (BDI) score was 9.63 ± 8.95 and the depressive group had significantly higher score compared to non-depressive group (18.5 ± 8.6 vs 4.4 ± 2.9, p < 0.001). There was no correlation between Beck Depression Inventory score and age of patients, ataxia severity, age at onset, or duration of the disease. The comparison between patient groups found no significant differences of white matter volumes. In contrast, we found reduction of gray matter volumes in the depressive group in medial and orbital region of frontal lobe and anterior cingulate gyri (p < 0.001). Regression analyses have shown that BDI scores were inversely correlated with gray matter volume at right superior frontal gyrus. Major depression is frequent in Friedreich's ataxia and possibly under recognized. Our results strongly suggest that this may not be a simply reactive phenomenon, but rather associated to structural abnormalities.