Macrostructural alterations of subcortical grey matter in psychogenic erectile dysfunction

Abstract

Psychogenic erectile dysfunction (ED) has been defined as the persistent inability to attain and maintain an erection sufficient to permit sexual performance. It shows a high incidence and prevalence among men, with a significant impact on the quality of life. Few neuroimaging studies have investigated the cerebral basis of erectile dysfunctions observing the role played by prefrontal, cingulate, and parietal cortices during erotic stimulation. In spite of the well-known involvement of subcortical regions such as hypothalamus and caudate nucleus in male sexual response, and the key role of nucleus accumbens in pleasure and reward, poor attention was paid to their role in male sexual dysfunction. In this study, we determined the presence of grey matter (GM) atrophy patterns in subcortical structures such as amygdala, hippocampus, nucleus accumbens, caudate nucleus, putamen, pallidum, thalamus, and hypothalamus in patients with psychogenic ED and healthy men. After Rigiscan evaluation, urological, general medical, metabolic and hormonal, psychological and psychiatric assessment, 17 outpatients with psychogenic ED and 25 healthy controls were recruited for structural MRI session. Significant GM atrophy of nucleus accumbens was observed bilaterally in patients with respect to controls. Shape analysis showed that this atrophy was located in the left medial-anterior and posterior portion of accumbens. Left nucleus accumbens volumes in patients correlated with low erectile functioning as measured by IIEF-5 (International Index of Erectile Function). In addition, a GM atrophy of left hypothalamus was also observed. Our results suggest that atrophy of nucleus accumbens plays an important role in psychogenic erectile dysfunction. We believe that this change can influence the motivation-related component of sexual behavior. Our findings help to elucidate a neural basis of psychogenic erectile dysfunction.

Figure 1. Segmentation of the deep grey matter structures.

Images are over imposed on MNI template.

Figure 2. Vertex-wise comparison of the nucleus accumbens between healthy controls and Psychogenic ED patients.

For vertex-wise shape analysis F-statistics have degrees of freedom of 1,40 giving p=0.165 (F=2), p=0.105 (F=2.75), p=0.086 (F=3.50), p=0.045 (F=4.25), p=0.030 (F=5). Family-wise error rate is controlled. Images are oriented according to neurological convention (the right hemisphere of the brain corresponds to the right side of the image).

Figure 3. Grey matter volume loss of left lateral hypothalamus in ED patients than healthy subjects.

Green colour describes the extent of the hypothalamus ROI. The significant voxels (family-wise error rate is controlled) are projected onto a Montreal Neurological Institute (MNI152) template and identified by colours ranging from red to yellow (the colored bar represents the p-value). All images are oriented according to radiological convention (the left hemisphere of the brain corresponds to the right side of the image).