Beyond a Differential Diagnosis: Cognitive and Morphometric Decoding of Information Processing Speed in Senior Adults with DSM-5 Mild Neurocognitive Disorders
Affiliations: [a] Department of Psychiatry, The Chinese University of Hong Kong, Tai Po Hospital, Hong Kong SAR, China
| [b] Guangzhou Brain Hospital, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
Correspondence:
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Correspondence to: Dr. Hanna Lu, G/F 27, Multicenter, Tai Po Hospital, Department of Psychiatry, The Chinese University of Hong Kong, Tai Po, Hong Kong SAR, China. Tel.: +852 2831 4305; Fax: +852 2667 5464; E-mail: hannalu@cuhk.edu.hk.
Abstract: Background: Processing speed has been highlighted as a diagnostic item for neurocognitive disorders (NCD) in DSM-5. The utility of information processing speed (IPS) enclosed with multiscale constructs in the diagnosis of NCD warrants exploration. Objective: We aimed to investigate the IPS with two types of measurements in the patients with NCD due to vascular disease (NCD-vascular) and NCD due to Alzheimer’s disease (NCD-AD), and examine the associations between IPS measures and morphometric features. Methods: The IPS was evaluated using trail making test (TMT) and flanker test (n = 204). Direct scores, derived scores, and reaction time (RT) were used as IPS measures. Further, surface-based morphometry cortical volume was calculated in a subsample (n = 44) with structural MRI data. Results: All IPS measures showed a significant value to differentiate NCD patients from healthy subjects. Only mean RT could distinguish NCD-AD from NCD-vascular groups. TMT-B score and difference score were correlated with gray matter volume (GMV) of inferior frontal gyrus, precuneus and superior temporal cortex. Mean RT was associated with the GMV of post-central gyrus (r = –0.327, p = 0.035), and executive speed was associated with inferior frontal cortex (r = –0.475, p = 0.001), cingulate gyrus (r = –0.497, p = 0.001), and superior temporal gyrus (r = –0.36, p = 0.019). Conclusion: The cognitive and morphometric correlates of IPS measures indicate that complex IPS might be decomposed into the domain-specific components with corresponding neural underpinnings. Our findings may also provide essential insights into the diagnostic item of NCD.
Keywords: Gray matter volume, information processing speed, morphometry, neurocognitive disorders, reaction time, trail making test
