Pontocerebellar volume deficits and ataxia in alcoholic men and women: no evidence for "telescoping"

Abstract

Introduction: Brain volume shrinkage is common in treatment-seeking patients with alcohol use disorders. Whether women are more vulnerable to brain dysmorphology than men despite lower alcohol consumption levels or shorter dependency ("telescoping effect") remains controversial and has not been considered with respect to infratentorial structures or their potential contribution to ataxia.

Methods: The 200 participants included 64 men and 31 women with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition alcohol dependence and 105 controls. An infratentorial region (pons, cerebellar hemispheres, vermis (anterior, posterior, and inferior sectors), fissures, cisterns, fourth ventricle) was quantified with atlas-based parcellation. To enable comparison of men and women, regional tissue volumes were expressed as ratios of tissue in the volume. Participants also completed quantitative ataxia testing.

Results: Total infratentorial and vermian tissue ratios were significantly smaller in alcoholics than controls; alcoholic women did not show disproportionately greater volume deficits than alcoholic men. A re-analysis including alcoholic men and women matched in alcohol consumption, onset age, abstinence duration, and age revealed again that alcoholic women did not have disproportionately greater regional vermian volume deficits than alcoholic men. Alcoholic men and women were impaired in all measures of ataxia, which correlated with low infratentorial tissue ratios in men.

Discussion: Alcoholic men showed deficits of pontocerebellar volume ratios, yet alcoholic women did not display signs of "telescoping". Further, alcoholic men and women both showed signs of ataxia of gait and balance, related to affected pontocerebellar systems in the men but not the women, suggesting the need to consider other neural substrates for ataxia in women.

Fig. 1

Coronal (a), axial (b), and sagittal (c) slices through the infratentorial volume from the FSE group template; d sagittal view of the region-of-interest masks for the superior, posterior, and inferior sectors of the cerebellar vermis

Fig. 2

Mean±SEM of the tissue volume ratios of the four regions of interest for the four subject groups

Fig. 3

Mean±SEM of the tissue volume ratios of the four regions of interest of the subset of alcohol men and alcoholic women matched on alcohol history variables. In general, the same pattern of sex differences observed in the full group (Fig. 2) endured in the matched groups

Fig. 4

Mean±SEM of the ataxia subtest scores for the four subject groups. In all cases, the alcoholic men and the alcoholic women performed significantly below the control groups

Fig. 5

Correlations between ataxia composite scores and the total infratentorial tissue volume ratio in the 63 alcoholic men who completed MRI and ataxia testing protocols