The primary goal of this study was to explore non-pharmacological approaches for screening mild cognitive impairment (MCI) by analyzing brain activation patterns using functional near-infrared spectroscopy (fNIRS) during verbal fluency tasks (VFT). The project aims to assess the application value of task-induced hemodynamic responses as potential biomarkers for identifying MCI. A secondary objective is to enhance early MCI detection, which could improve interventions and delay the progression to Alzheimer's disease.
A total of 50 subjects were recruited in this study, including 25 patients with MCI and 25 normal elderly volunteers. A 26-channel fNIRS instrument was used when the participant performed the VFT to measure the integral value, centroid value, slope, and mean value of the activation patterns of the prefrontal and temporal lobes of the subjects.
When performing the VFT, the mean of vegetables, fruits and total words in MCI group were significantly lower than that in normal elderly group [(5.88±1.75) vs. (8.04±1.99), (6.21±1.61) vs. (7.33±2.01), (19.58±4.31) vs. (23.83±4.53) ；t=-4.01, P＜0.001, t=-2.14, P=0.038, t=-3.33, P=0.002]. In addition, the integral value of prefrontal hemodynamic in MCI group was significantly lower than that in normal elderly group [-3.10(-31.36,67.12) mmol ·mm vs. 35.16(18.39,72.62) mmol ·mm; Z=-2.13, P=0.034].
Patients with MCI produce fewer category words during VFT, indicating a deficiency in lexical generation, and they also exhibit lower prefrontal hemodynamic response intensity compared to normal elderly controls. This finding is consistent with most existing research. Specifically, MCI patients show a significant reduction in the number of category words generated during VFT tasks, highlighting their lexical generation deficits. Further analysis indicates that the activation intensity of the prefrontal cortex is also significantly reduced in MCI patients when performing VFT tasks. The prefrontal cortex scores detected by fNIRS can provide important biomarkers for distinguishing MCI patients. The prefrontal region plays a crucial role in cognitive control, language generation, and executive functions, and the deficiencies observed in MCI patients in these areas may be due to insufficient activation of the prefrontal cortex.
The findings have important implications for physiotherapy and cognitive rehabilitation. By identifying specific activation deficits in the prefrontal cortex during VFT, this study suggests that fNIRS could be used as a practical screening tool in clinical settings. The results could support physiotherapists in implementing more personalized cognitive rehabilitation strategies, enhancing early diagnosis, and ultimately improving patient management.
Mild Cognitive Impairment, Verbal Fluency Task
Cortical Activation Patterns
