The neural correlates of perceived energy levels in older adults with late-life depression

Charlene L M Lam,Ho-Ling Liu,Shwu-Hua Lee,Chemin Lin,Jenny Yiend,Yau-Yau Wai,Chih-Mao Huang,Tatia M C Lee

doi:10.1007/s11682-018-9940-y

Abstract

Late-life depression is common among older adults. Although white-matter abnormality is highly implicated, the extent to which the corticospinal tract is associated with the pathophysiology of late-life depression is unclear. The current study aims to investigate the white-matter structural integrity of the corticospinal tract and determine its cognitive and functional correlates in older adults with late-life depression. Twenty-eight older adults with clinical depression and 23 healthy age-matched older adults participated in the study. The white matter volume and the white matter hyperintensities (WMHs) of the corticospinal tract, as well as the global WMHs, were measured. Psychomotor processing speed, severity of depression, perceived levels of energy and physical functioning were measured to examine the relationships among the correlates in the depressed participants. The right corticospinal tract volume was significantly higher in depressed older adults relative to healthy controls. Moreover, the right corticospinal tract volume was significantly associated with the overall severity of depression and accounted for 17% of its variance. It further attenuated the relationship between the severity of depression and perceived levels of energy. Our findings suggested that higher volume in the right corticospinal tract is implicated in LLD and may relate to lower perceived levels of energy experienced by older adults with depression.

Highlights

Late-life depression is common among older adults
This study extended the previous studies by using analyses based on regions of interest (ROIs) to examine the findings on the abnormality of corticospinal tracts in LLD and explore its cognitive and functional correlates
Depressed older adults did not have higher whole brain white matter hyperintensities (WMHs) volume comparing to the healthy controls (F1,39 = 0.26, p > .05).With respect to the WMHs volume in the bilateral corticospinal tract, we did not observe any WMHs in 68.2% of the patients and 52.4% of the healthy participants

Summary

Introduction

Late-life depression is common among older adults. white-matter abnormality is highly implicated, the extent to which the corticospinal tract is associated with the pathophysiology of late-life depression is unclear. The right corticospinal tract volume was significantly associated with the overall severity of depression and accounted for 17% of its variance It further attenuated the relationship between the severity of depression and perceived levels of energy. Our findings suggested that higher volume in the right corticospinal tract is implicated in LLD and may relate to lower perceived levels of energy experienced by older adults with depression. Apart from the dysregulated frontostriatal pathway, the vascular depression hypothesis has been proposed to account for the psychomotor disturbance in LLD This model posits that cerebrovascular changes in the white matter (WM) are crucial in the pathogenesis of LLD (Alexopoulos 2005; Alexopoulos et al 1997). There is a dearth of research examining the WMHs in the corticospinal tract of patients with LLD (Fig. 1)

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Conclusion