Study of Prefrontal Blood Flow in Dementia Patients Using Near‐Infrared

Abstract

SUMMARY The category frequency task has become one of the most important tools for measuring brain function. In this investigation, we used near‐infrared spectroscopy to examine the prefrontal blood flow in the brain, using a category fluency task function test to determine if this method can be used to diagnose dementia in the early stages. We examined 21 healthy volunteer students (age 21.0±1.4; 11 males and 10 females) and 50 patients with dementia (age 83.3±6.7; 12 males and 38 females; mini mental status: 0–22). The category fluency task required the subjects to produce nouns belonging to the category of vegetables. Our results showed that the healthy volunteer students had an increase in the blood flow while performing this task. On the other hand, the dementia patients did not show any relevant increase in blood flow while performing this task. The results suggest that the combination of the category fluency task and near‐infrared spectroscopy could be used as one more tool for the diagnosis of dementia.

Prefrontal Cerebral Oxygenated Hemoglobin Concentration during the Category Fluency and Finger-Tapping Tasks in Adults with and without Mild Cognitive Impairment: A Near-Infrared Spectroscopy Study

“…Specifically, young participants had a higher oxyhemoglobin signal during category fluency than the elderly participants did, as shown in Figure 4 and Figure 5 . This result is consistent with those of previous studies that have demonstrated decreased oxyhemoglobin signal changes in elderly individuals compared to young individuals, which were further decreased in patients with dementia [ 8 , 32 ]. In contrast, young individuals showed a decreased oxyhemoglobin signal during the finger-tapping task.…”

“…In a previous study, the cerebral oxyhemoglobin signals were measured in 21 healthy volunteer students and 50 patients with dementia using near-infrared (NIR) spectroscopy [ 8 ]. The advantages of NIR spectroscopy include relative insensitivity to movement, portability, and affordability, which permit the designing of tasks for assessing populations, such as children or older people.…”

“…The advantages of NIR spectroscopy include relative insensitivity to movement, portability, and affordability, which permit the designing of tasks for assessing populations, such as children or older people. They found that during the category fluency task, healthy young participants presented with increased blood flow; in contrast, participants with dementia demonstrated no changes in the prefrontal blood flow [ 8 ]. In another study, the authors reported that during the category fluency tasks, healthy elderly controls demonstrated a higher cerebral oxyhemoglobin signal in the left cerebral hemisphere compared to patients with dementia [ 9 ].…”

“…In another study, the authors reported that during the category fluency tasks, healthy elderly controls demonstrated a higher cerebral oxyhemoglobin signal in the left cerebral hemisphere compared to patients with dementia [ 9 ]. A previous study reported that compared to young controls, patients with dementia had decreased cerebral blood flow during cognitive tasks [ 8 ].…”

Comparison of Cerebral Blood Volume during Cold and Warm Stimulation in Elderly and Young Subjects

“…In the present study, young individuals also showed higher values; however, no significant increase in young subjects was at rest and during the task compared to the elderly subjects. In the report and other studies, a significant increase was in oxygenated hemoglobin concentration at rest, during the control condition task and the task [ 19 - 20 ]; however, the task used was one in which the frontal lobe was activated. On the other hand, the task conducted in this study required sensory functions and judgmental abilities as the switch was pressed with warm or cold stimuli.…”