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

Figures

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  Figure 1. The measurement tasks included the category fluency task, finger-tapping task, dual task with both tasks, control task 1, and control task 2. Control task 1 involved pronunciation of the Japanese characters “a, i, u, e, o”. Control task 2 involved keeping the index finger and thumb together.

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  Figure 2. Control task 2 condition. Control task 2 involved keeping the index finger and thumb together.

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  Figure 3. Probe set of WOT100. WOT100 has 10 measurement channels in the prefrontal cortex. Channels 7, 8, 9, and 10 are in the right prefrontal cortex region while channels 13, 14, 15, and 16 are in the corresponding left region. The light-emitting diode and light-receiving element are shown by 3–6.

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  Figure 4. Changes in raw oxyhemoglobin levels of the right channels before normalization. Representative data from young controls (a), elderly participants without mild cognitive impairment (b), and elderly participants with mild cognitive impairment (c) are shown.

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  Figure 5. Changes in raw oxyhemoglobin levels of the left channels before normalization. Representative data from young controls (a), elderly participants without mild cognitive impairment (b), and elderly participants with mild cognitive impairment (c) are shown.

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  Figure 6. Condition-specific differences in normalized oxyhemoglobin signal of right channels. Figure 6 shows the normalized oxyhemoglobin signal for each task in the right channel. The blue color represents data from rest (average of right channel). The deep orange color represents data from the category fluency task (average of right channel). The gray color represents data from dual tasks (category fluency task and finger-tapping task; average of right channel). The light orange color represents data from the finger-tapping task (average of right channel).

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  Figure 7. Condition-specific differences in normalized oxyhemoglobin signal of left channels. Figure 7 shows the normalized oxyhemoglobin signal for each task in the left channel. The blue, deep orange, gray, and light orange colors represent data from rest, the category fluency task, dual task, and finger-tapping task, respectively.