Cognitive and Spontaneous Brain Activity in Nonaddictive Smartphone Users Among Older Adults in China: Cross-Sectional Study

Abstract

Background: The effects of smartphone use on mental health and brain activity in adolescents have received much attention; however, the effects on older adults have received little attention. As more and more older adults begin to use smartphones, exploring the effects of nonaddictive smartphone use on mental health, cognitive function, and brain activity in older adults is imperative.

Objective: This study aimed to examine differences in cognitive performance, emotional symptoms (depression, anxiety, and insomnia), and brain functional activity between older adults who use smartphones and those who do not.

Methods: A total of 1014 community-dwelling older adults aged 60 years and above were surveyed in a rural area of China. Participants were categorized into 2 groups based on their smartphone use status. The Patient Health Questionnaire, Generalized Anxiety Disorder Scale, Insomnia Severity Index, and Montreal Cognitive Assessment-Basic were used to evaluate the symptoms of depression, anxiety, insomnia, and cognitive function of the participants by trained medical staff. To explore neural mechanisms, a subsample of 130 participants (89 smartphone users and 41 nonusers) was selected using stratified random sampling for resting-state functional magnetic resonance imaging scanning. Participants with contraindications for magnetic resonance imaging (eg, metal implants or claustrophobia) or who refused to participate were excluded. Functional brain activity was analyzed and compared between groups.

Results: Among all 1015 older adults, 641 reported using smartphones, while 373 reported never using smartphones. Older adults who use smartphones exhibited better cognitive function compared with those who never use smartphones (z=3.806, P<.001), especially in the domains of fluency (z=3.025, P=.002) and abstraction (z=5.311, P<.001). However, there were no significant differences in levels of depression (z=0.689, P=.49), anxiety (z=0.934, P=.35), and insomnia (z=0.340, P=.73). In terms of the magnetic resonance imaging findings, a total of 130 participants completed functional magnetic resonance imaging scanning, including 89 who use smartphones and 41 who never use smartphones, and results showed that older adults who were smartphone users exhibited higher degree centrality values in the left parahippocampal gyrus.

Conclusions: These findings suggest that smartphone use among older adults is associated with better cognitive performance and fewer emotional symptoms, potentially linked to enhanced brain activity in key cognitive regions. Promoting digital engagement may offer cognitive and emotional benefits for aging populations. Longitudinal studies are warranted to examine causal relationships.

Keywords: aged; cognition; fMRI; functional magnetic resonance imaging; mental health; mobile phone; older adults; smartphone.

Figure 1.. The flowchart of the whole study. fMRI: functional magnetic resonance imaging; GAD-7: Generalized Anxiety Disorder; ISI: Insomnia Severity Index; MoCA-B: Montreal Cognitive Assessment-Basic; MRI: magnetic resonance imaging; PHQ-9: Patient Health Questionnaire; PSU: problematic smartphone use; SAS-SV: Smartphone Addiction Scale-Short Version.

Figure 2.. The difference in cognitive scores between the USm group and the NUS group. Scores for each domain were normalized before visualization to enable comparison across domains. USm: use smartphone; NUS: never use smartphone. * P<.005, ** P<.001.

Figure 3.. Brain regions showing significantly increased degree centrality in the USm group compared to the NUS group. The cluster in the left parahippocampal gyrus is visualized in sagittal slices at x=–28, –24, and –20 (MNI coordinates). The results were set at a threshold at voxel-wise P<.001 and cluster-level P<.05 (AlphaSim corrected). The color bar indicates t test values. L: left; MNI: Montreal Neurological Institute; NUS: never use smartphone; R: right; USm: use smartphone.