Long-Term Effects of Postearthquake Distress on Brain Microstructural Changes

Atsushi Sekiguchi,Seishu Nakagawa,Sugiko Hanawa,Rui Nouchi,Yuka Kotozaki,Ryuta Kawashima,Yasuyuki Taki,Tsuyoshi Araki,Atsushi Sakuma,Hikaru Takeuchi,Carlos Makoto Miyauchi,Motoaki Sugiura

doi:10.1155/2014/180468

Abstract

Stressful events can have both short- and long-term effects on the brain. Our recent investigation identified short-term white matter integrity (WMI) changes in 30 subjects soon after the Japanese earthquake. Our findings suggested that lower WMI in the right anterior cingulum (Cg) was a pre-existing vulnerability factor and increased WMI in the left anterior Cg and uncinate fasciculus (Uf) after the earthquake was an acquired sign of postearthquake distress. However, the long-term effects on WMI remained unclear. Here, we examined the 1-year WMI changes in 25 subjects to clarify long-term effects on the WMI. We found differential FAs in the right anterior Cg, bilateral Uf, left superior longitudinal fasciculus (SLF), and left thalamus, suggesting that synaptic enhancement and shrinkage were long-term effects. Additionally, the correlation between psychological measures related to postearthquake distress and the degree of WMI alternation in the right anterior Cg and the left Uf led us to speculate that temporal WMI changes in some subjects with emotional distress occurred soon after the disaster. We hypothesized that dynamic WMI changes predict a better prognosis, whereas persistently lower WMI is a marker of cognitive dysfunction, implying the development of anxiety disorders.

Highlights

Stressful events have both short- and long-term effects on the brain [1, 2]
We found that lower white matter integrity (WMI) in the right anterior Cg before the earthquake was a preexisting vulnerability factor for postearthquake distress, and that increased WMI in the left anterior Cg and uncinate fasciculus (Uf) after the earthquake was an acquired sign of post-earthquake distress [10]
We found differential fractional anisotropy (FA) to be a significant main effect of time period in the right anterior Cg, bilateral Uf, left superior longitudinal fasciculus (SLF), and the thalamus (Table 2, Figure 1). post hoc correlation analyses revealed a significant positive correlation between the FA changes in the right anterior Cg from pre to followup and clinician-administered PTSD scale (CAPS) scores at post (Spearman’s Rho = 0.414, P = 0.039, Figure 2(a)) and a significant negative correlation between the FA changes in the left Uf from post to followup and STAIstate scores at post (r = −0.440, P = 0.028, Figure 2(b))

Summary

Introduction

Stressful events have both short- and long-term effects on the brain [1, 2]. Acute and chronic stress-induced brain microstructural changes have been observed in prefrontal areas in rodents [3]. Recent human studies identified white matter microstructural changes due to stress using diffusion tensor imaging (DTI) methods [4] in subjects with posttraumatic stress disorder (PTSD) [5,6,7,8] as well as healthy survivors of a disaster [9] These studies revealed lower white matter integrity (WMI) in several brain regions, including the cingulum (Cg) and uncinate fasciculus (Uf), in subjects who developed PTSD [5,6,7,8] (i.e., long-term effect) and in individuals soon after a disaster [9] (i.e., short term effect). We found that lower WMI in the right anterior Cg before the earthquake was a preexisting vulnerability factor for postearthquake distress, and that increased WMI in the left anterior Cg and Uf after the earthquake was an acquired sign of post-earthquake distress [10]

Methods

Results

Discussion

Conclusion