Altered hippocampal subfield volumes are associated with memory and executive function in patients with type 2...

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.

To investigate changes in hippocampal subregion volumes in patients with T2DM and their relationship with cognitive function impairment.

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.

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.

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.