Abstract
BACKGROUND: Increasing evidence has shown that hippocampal damage serves as a marker of early cognitive decline in patients with type 2 diabetes mellitus (T2DM); however, the association between hippocampal subregion volume changes and cognitive decline in different dimensions remains unclear. AIM: To investigate changes in hippocampal subregion volumes in patients with T2DM and their relationship with cognitive function impairment. METHODS: Sixty patients with T2DM and 32 healthy controls were recruited. All participants underwent a 3.0 T magnetic resonance scan and a series of clinical assessments. Hippocampal subfield volumes were determined using FreeSurfer 7.4.1. A two-sample t-test was used to evaluate group differences. Partial correlation analysis was performed to assess the relationship between hippocampal subregion volumes and cognitive function. (a) P < 0.05 was considered statistically significant. RESULTS: Compared with controls, the volume of right hippocampus-amygdala transition area (t = -3.053, P = 0.003) in patients with T2DM was significantly reduced, which was negatively correlated with the required time of the Trail Making Test (TMT)-A (r = -0.331, P = 0.028) and TMT-B (r = -0.402, P = 0.007) and positively correlated with the scores of Symbol Digit Modalities Test (r = 0.381, P = 0.011), Auditory Verbal Learning Test (AVLT)-N7 (r = 0.309, P = 0.041), and Digital Span Test (r = 0.300, P = 0.048). The volume of the right molecular layer (t = -2.998, P = 0.004) was also significantly reduced, which was positively associated with the scores of AVLT-N7 (r = 0.311, P = 0.045). In addition, the left hippocampal fissure volume (t = 3.617, P = 0.002) was significantly increased in patients with T2DM. CONCLUSION: Declines in cognitive performance, especially memory and executive function, are linked to changes in the volumes of the right hippocampus-amygdala transition area and right molecular layer in patients with T2DM.