The present pilot study was aimed at conducting a comparative analysis of the level of activation in the prefrontal cortex among a normal elderly group and amnestic and nonamnestic mild cognitive impairment (MCI) groups and investigating the presence of neural compensatory mechanisms according to types of MCI and different cognitive tasks. We performed functional near-infrared spectroscopy (fNIRS) along with cognitive tasks, including two-back test, Korean color word Stroop test, and semantic verbal fluency task (SVFT), to investigate hemodynamic response and the presence of neural compensation and neuroplasticity in the prefrontal cortex of patients with amnestic and nonamnestic MCI compared with a healthy elderly group. During the two-back test, there was no significant difference in the bilateral region-of-interest (ROI) analysis in the three groups. During the Stroop test, right-sided hyperactivation compared to the left side during the task was shown in the nonamnestic MCI and normal groups with statistical significance. Mean acc∆HbO2  on the right side was highest in the nonamnestic MCI group (0.30 μM) followed by the normal group (0.07 μM) and the amnestic MCI group (-0.10 μM). Otherwise, intergroup ROI analysis of acc∆HbO2 in these activated right sides showed no significant difference. During the VFT test, there was no significant difference in the bilateral region-of-interest analysis in the three groups. The highest mean acc∆HbO2 was shown in the normal group (0.79 μM) followed by the nonamnestic MCI group (0.52 μM) and the amnestic MCI group (0.21 μM). Otherwise, there was no significant difference between groups. The hemodynamic response during fNIRS showed different findings according to MCI types and cognitive tasks. Among the three tasks, the Stroop test showed results that were suggestive of neural compensatory mechanisms in the prefrontal cortex in nonamnestic MCI.

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This study was performed to investigate the usefulness of functional near-infrared spectroscopy (fNIRS) by conducting a comparative analysis of hemodynamic activation detected by fNIRS and positron emission tomography (PET) and magnetic resonance imaging (MRI) in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Participants were divided into four groups: the subjective memory impairment (SMI), amnestic MCI (aMCI), non-amnestic MCI (naMCI), and AD groups. We recorded the hemodynamic response during the semantic verbal fluency task (SVFT) using a commercial wireless continuous-wave NIRS system. The correlation between the parameters of the neuroimaging assessments among the groups was analyzed. Region of interest-based comparisons showed that the four groups had significantly different hemodynamic responses during SVFT in the bilateral dorsolateral prefrontal cortex (DLPFC). The linear mixed effect model result indicates that the mean ΔHbO2 from the bilateral DLPFC regions showed a significant positive correlation to the overall FDG-PET after controlling for age and group differences in the fNIRS signals. Amyloid PET signals tended to better differentiate the AD group from other groups, and fNIRS signals tended to better differentiate the SMI group from other groups. In addition, a comparison between the group pairs revealed a mirrored pattern between the hippocampal volume and hemodynamic response in the DLPFC. The hemodynamic response detected by fNIRS showed a significant correlation with metabolic and anatomical changes associated with disease progression. Therefore, fNIRS may be considered as a screening tool to predict the hemodynamic and metabolic statuses of the brain in patients with MCI and AD.

Purpose Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation and persistent respiratory symptoms. Several symptom‐related questionnaires have been validated to improve understanding for patient with COPD. We aimed to systematically translate the English version of the Lung Information Needs Questionnaire (LINQ) into Korean and to verify the reliability, validity and clinical implications in comprehensive pulmonary rehabilitation (PR). Methods The original version of LINQ was translated into Korean by two translators and reviewed by the translation committee. It was then reverse translated back into English. The committee compared the reconciled version in Korean and the original version in English. A cognitive debriefing was performed on the pre‐final version, and a final version, K‐LINQ, was obtained. A test‐retest method for the analysis of reliability was performed within 2 weeks. Concurrent validity analysis was performed using Pearson correlation test of the K‐LINQ and other evaluation tools. Results A total of 110 patients were enrolled. The length, readability, understanding and suitability of the questionnaire rated well in scores for face validity of 52 Korean patients with COPD. No significant correlation was derived from the total K‐LINQ and each domain with other scales such as mMRC, K‐CAT and K‐LCADL. The intra‐class correlation coefficient of total score K‐LINQ showed high reliability. Patients who attended PR showed significantly poor pulmonary function or more severe symptoms. In addition, a significantly lower score in total score and exercise domain of K‐LINQ were confirmed in the group of PR attendees. Conclusions We translated the LINQ into Korean, implemented cross‐cultural adaptation and verified its validity and reliability. K‐LINQ can now be useful in various clinical and research fields in the Republic of Korea and could serve a complementary role and become an axis of successful treatment strategies, including a comprehensive PR programme.