[Clock drawing task as screening for cognitive impairment in the elderly population]

Aluminum-Induced Cognitive Impairment and PI3K/Akt/mTOR Signaling Pathway Involvement in Occupational Aluminum Workers

Epidemiological studies indicate that long-term occupational exposure to aluminum (Al) causes neurotoxicity and cognitive impairment. While the molecular underpinnings associated with workers' cognitive impairment is unclear, one mechanism may involve Al-induced PI3K/Akt/mTOR activation and neuronal cell death, which impairs learning and memory in rats. Here, we sought to determine whether PI3K/Akt/mTOR is also associated with cognitive impairment in Al-exposed occupational workers. Cognitive function was screened by Mini-Mental State Examination (MMSE) and Clock-Drawing Test (CDT), and serum Al and PI3K/Akt/mTOR-associated gene expression was quantified. A negative correlation between serum Al and scores of MMSE and CDT was found, which might relate with downregulation of PI3K/Akt/mTOR. To determine the role of the PI3K/Akt/mTOR pathway cognitive function, we treated zebrafish with Al and observed a profound impairment in learning and memory. Increased brain Al levels was associated with decreased expression of PI3K/Akt/mTOR in Al-exposed zebrafish. Finally, rapamycin, an mTOR inhibitor, was added to isolate the role of mTOR specifically in the Al exposed zebrafish. The results suggested that Al induces learning and memory deficits by downregulating PI3K, Akt, and mTOR1 expression and inducing neuronal cell death like rapamycin group. This study indicates that aluminum exposure can cause cognitive impairment through PI3K/Akt/mTOR pathway, with mTOR activity being a critical player involved in this mechanism. Future studies are necessary to further characterize the role of PI3K/Akt/mTOR1 signaling in Al-induced neurocognitive decline among Al occupational workers. These findings draw attention to Al risk exposure among occupational workers and the need to implement novel safety and protective measures to mitigate neurocognitive health risks in the Al industrial workspace.

Quantitative and Qualitative Analyses of the Clock Drawing Test in Fall and Non-Fall Patients with Alzheimer's Disease

Aim

The clock drawing test (CDT) is widely used as a visual spatial ability test and screening test for dementia patients. The appearance frequency of qualitative errors obtained through the qualitative analysis of CDT may be related to the participant's falls. The aim of this study was to clarify the difference in the number of people who presented with qualitative errors in the CDT between a fall and non-fall group of patients with Alzheimer's disease (AD).

Methods

The CDT was implemented for 47 patients with AD. A quantitative analysis was conducted, and a qualitative analysis was performed for errors. The patients were divided into two groups based on their history of falls over the past year. The results of the CDT quantitative analysis were tested using the Mann-Whitney U test, and Fisher's exact test was employed to determine the difference in the number of people who presented with error types between the two groups (fall group, non-fall group) in the CDT qualitative analysis.

Results

In the quantitative analysis, a significant difference was found for the total scores, with the total CDT score of the fall group (n = 22) significantly lower than that of the non-fall group (n = 25) (p = 0.006, effect size: φ = 0.40). In the qualitative analysis, a significantly higher number of patients in the fall group than in the non-fall group presented with a conceptual deficit (p =0.001, φ = 0.51). No differences were found in the number of patients in the two groups who presented with the other five error types.

Conclusions

These results showed that a lower score in the CDT quantitative analysis might suggest an increased risk of falls. It was also clarified that a larger number of patients in the fall group than in the non-fall group presented with a conceptual deficit of the qualitative error types in the CDT. Therefore, these results suggest that the appearance of a conceptual deficit may be an index for the selection of patients with AD prone to falling when implementing fall prevention measures.