Virchow-Robin space dilatation may predict resistance to antidepressant monotherapy in elderly patients with depression.

BACKGROUND: Late-life depressive disorders have been linked to cerebrovascular disease (the vascular depression hypothesis). Treatment resistance may be associated with vascular-based lesions in the white matter and basal ganglia. Virchow-Robin spaces (VRS) are cerebrospinal fluid spaces associated with microangiopathy of small cerebral vessels. This study tested the hypothesis that dilation of Virchow-Robin spaces seen on Magnetic Resonance Imaging (MRI) is associated with treatment resistance in elderly depressed individuals. METHODS: 50 patients with late-onset (age over 60 years) major depressive disorder (29 responders to monotherapy, 21 non-responders to monotherapy) and 35 normal volunteers were recruited. Assessment of deep white matter lesions [WML] and periventricular hyperintensities [PVH] (both with the Scheltens rating scale score, [Scheltens, P., Barkhof, F., Leys, D., et al. (1993) A semiquantative rating scale for the assessment of signal hyperintensities on magnetic resonance imaging. J Neurol Sci;114(1):7-12.]) and the severity of VRS dilatation (using a new scale) were scored from MRI images. Statistical group comparisons and multiple regression analyses were performed to quantify the relationship between imaging features and clinical outcome. RESULTS: There was a trend for greater WML Scheltens scores in the monotherapy resistant group compared to responders and control subjects, but only using the basal ganglia VRS score was there a statistically significant difference. A score of 2 or greater on the VRS score was 80% sensitive and 62% specific in predicting non-response to antidepressant monotherapy. The VRS score accounted for 38% of the variance in the multiple regression model and the PVH score, which was an independent predictor of outcome, contributed another 6%. LIMITATIONS: Numbers are small and type II errors possible, especially for the Scheltens ratings. Treatment response was limited to response or non-response to monotherapy and was retrospectively derived. The VRS scale was originally designed for use in patients with vascular dementia and has not been used before in affective disorders. Although all depressed subjects were late-onset, it is possible that depression led to vascular disease rather than vice versa. CONCLUSION: VRS dilatation is common in diseases associated with microvascular abnormality, which is the presumed basis of vascular depression in the elderly. VRS score may be useful in determining which patients are less likely to respond to antidepressant monotherapy. Prospective studies of patients with a wider range of treatment responses are indicated.

Abnormalities of CSF flow patterns in the cerebral aqueduct in treatment-resistant late-life depression: a potential biomarker of microvascular angiopathy.

There is growing evidence that microvascular angiopathy (MVA) plays an important role in the development of dementia and affective disorders in older people. At currently available image resolutions it is not possible to image directly the vascular changes associated with MVA, but the effects on blood and cerebrospinal fluid (CSF) flow may be detectable. The aim of this study was to investigate a potential biomarker for MVA based on MRI of abnormalities in CSF flow. Since there is considerable indirect evidence that treatment resistance in late-onset depressive disorder is related to MVA, we assessed the method in a group of 22 normal volunteers and 29 patients with responsive (N=21) or treatment-resistant (N=8) late-onset depressive disorder. Single-slice quantified phase-contrast (PC) images of cerebral blood and CSF flow were collected at 15 points over a cardiac cycle, and the resulting flow curves were parameterized. Significant differences in the CSF flow (width of systolic flow peak and diastolic flow volume, both P<0.01) through the cerebral aqueduct were observed for the group of treatment-resistant patients when compared to age matched controls. No significant difference was observed for a group of 21 patients with treatment-responsive depression. The findings support the hypothesis that MR measurement of CSF flow abnormalities provides a biomarker of MVA, and thus could have application in a wide range of age-related diseases.

Neurological findings in late-onset depressive disorder: comparison of individuals with and without depression.

BACKGROUND: Organic factors are thought to be important in late-life depressive disorder but there have been few studies specifically of neurological signs. AIMS: To compare neurological signs in a group of patients with late-onset depression and in healthy controls. METHOD: A case-control study comparing 50 patients with depression and 35 controls on three measures of central nervous system (CNS) signs: a structured CNS examination, the Neurological Evaluation Scale (NES) and the Webster rating scale for parkinsonism. RESULTS: After adjusting for major depression at the time of evaluation and prescription of tranquillisers, ratings on two of the NES sub-scales (complex motor sequencing and 'other' signs) and on the Webster scale were significantly higher (more impaired) in patients compared with controls (P<0.05). With logistic regression, the NES was the main measure predictive of group outcome. There were no differences in scores of vascular risk or white matter but patients had patients had more atrophy. CONCLUSIONS: The findings add to the evidence that late-life depression is associated with organic brain dysfunction, perhaps mediated by neurodegeneration or subtle vascular impairment. The use of the NES in subjects with depression should be replicated.