Differential Associations of White Matter Brain Age With Language-Related Mechanisms in Word-Finding Ability Across the Adult Lifespan

Pin-Yu Chen; Chang-Le Chen; Hui-Ming Tseng; Yung-Chin Hsu; Chi-Wen Christina Huang; Wing P Chan; Wen-Yih I Tseng

doi:10.3389/fnagi.2021.701565

Differential Associations of White Matter Brain Age With Language-Related Mechanisms in Word-Finding Ability Across the Adult Lifespan

Front Aging Neurosci. 2021 Sep 3:13:701565. doi: 10.3389/fnagi.2021.701565. eCollection 2021.

Authors

Pin-Yu Chen¹, Chang-Le Chen¹, Hui-Ming Tseng², Yung-Chin Hsu³, Chi-Wen Christina Huang^{4

5}, Wing P Chan^{4

5}, Wen-Yih I Tseng^{1

2}

Affiliations

¹ Molecular Imaging Centre, National Taiwan University, Taipei, Taiwan.
² Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan.
³ AcroViz Technology Inc., Taipei, Taiwan.
⁴ Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
⁵ Department of Radiology, College of Medicine, Taipei Medical University, Taipei, Taiwan.

Abstract

Research on cognitive aging has established that word-finding ability declines progressively in late adulthood, whereas semantic mechanism in the language system is relatively stable. The aim of the present study was to investigate the associations of word-finding ability and language-related components with brain aging status, which was quantified by using the brain age paradigm. A total of 616 healthy participants aged 18-88 years from the Cambridge Centre for Ageing and Neuroscience databank were recruited. The picture-naming task was used to test the participants' language-related word retrieval ability through word-finding and word-generation processes. The naming response time (RT) and accuracy were measured under a baseline condition and two priming conditions, namely phonological and semantic priming. To estimate brain age, we established a brain age prediction model based on white matter (WM) features and estimated the modality-specific predicted age difference (PAD). Mass partial correlation analyses were performed to test the associations of WM-PAD with the cognitive performance measures under the baseline and two priming conditions. We observed that the domain-specific language WM-PAD and domain-general WM-PAD were significantly correlated with general word-finding ability. The phonological mechanism, not the semantic mechanism, in word-finding ability was significantly correlated with the domain-specific WM-PAD. In contrast, all behavioral measures of the conditions in the picture priming task were significantly associated with chronological age. The results suggest that chronological aging and WM aging have differential effects on language-related word retrieval functions, and support that cognitive alterations in word-finding functions involve not only the domain-specific processing within the frontotemporal language network but also the domain-general processing of executive functions in the fronto-parieto-occipital (or multi-demand) network. The findings further indicate that the phonological aspect of word retrieval ability declines as cerebral WM ages, whereas the semantic aspect is relatively resilient or unrelated to WM aging.

Keywords: brain age prediction; diffusion MRI; domain-specific language mechanisms; white matter; word-finding ability.