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Reduced dorsolateral prefrontal cortical hemodynamic response in adult obsessive-compulsive disorder as measured by near-infrared spectroscopy during the verbal fluency task.

Hirosawa R, Narumoto J, Sakai Y, Nishida S, Ishida T, Nakamae T, Takei Y, Fukui K - Neuropsychiatr Dis Treat (2013)

Bottom Line: Z-scores for changes in the concentration of oxygenated hemoglobin were compared between the OCD patients and controls in 14 channels set over the left and right dorsolateral prefrontal cortex and frontopolar areas.During the verbal fluency task, significant task-related activation was detected in both the OCD group and the controls.Changes in oxygenated hemoglobin concentration in the right dorsolateral prefrontal cortex were significantly smaller in the OCD group than in the controls, but were not statistically significant after correction for multiple comparisons.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto.

ABSTRACT

Background: Near-infrared spectroscopy has helped our understanding of the neurobiological mechanisms of psychiatric disorders and has advantages including noninvasiveness, lower cost, and ease of use compared with other imaging techniques, like functional magnetic resonance imaging. The verbal fluency task is the most common and well established task used to assess cognitive activation during near-infrared spectroscopy. Recent functional neuroimaging studies have shown that the orbitofrontal cortex and other brain regions, including the dorsolateral prefrontal cortex, may play important roles in the pathophysiology of obsessive-compulsive disorder (OCD). This study aimed to evaluate hemodynamic responses in the dorsolateral prefrontal cortex in patients with OCD using near-infrared spectroscopy during the verbal fluency task and to compare these with dorsolateral prefrontal cortex responses in healthy controls.

Methods: Twenty patients with OCD and 20 controls matched for age, gender, handedness, and estimated intelligence quotient participated in this study. The verbal fluency task was used to elicit near-infrared spectroscopic activation and consisted of a 30-second pre-task, followed by three repetitions of a 20-second verbal fluency task (total 60 seconds), followed by a 70-second post-task period. The near-infrared spectroscopy experiment was conducted on the same day as surveys of obsessive-compulsive symptoms, depression, and anxiety. Z-scores for changes in the concentration of oxygenated hemoglobin were compared between the OCD patients and controls in 14 channels set over the left and right dorsolateral prefrontal cortex and frontopolar areas.

Results: During the verbal fluency task, significant task-related activation was detected in both the OCD group and the controls. Changes in oxygenated hemoglobin concentration in the right dorsolateral prefrontal cortex were significantly smaller in the OCD group than in the controls, but were not statistically significant after correction for multiple comparisons.

Conclusion: Patients with OCD have reduced prefrontal, especially right dorsolateral prefrontal, cortical hemodynamic responses as measured by near-infrared spectroscopy during the verbal fluency task. These results support the hypothesis that the dorsolateral prefrontal cortex plays a role in the pathophysiology of OCD.

No MeSH data available.


Related in: MedlinePlus

Localization matrices mapped over a standard brain template. Areas shown in yellow represent matrix of guidance channels. (A) Matrix of guidance in which areas shown in orange represent regions of interest. (B) Patients with obsessive-compulsive disorder had significantly smaller changes in oxygenated hemoglobin concentration than controls at channel 18 (orange), localized near the right lateral prefrontal region.
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f2-ndt-9-955: Localization matrices mapped over a standard brain template. Areas shown in yellow represent matrix of guidance channels. (A) Matrix of guidance in which areas shown in orange represent regions of interest. (B) Patients with obsessive-compulsive disorder had significantly smaller changes in oxygenated hemoglobin concentration than controls at channel 18 (orange), localized near the right lateral prefrontal region.

Mentions: First, changes in the oxygenated hemoglobin concentration in each of the 14 channels were analyzed. Channel groupings corresponded to approximate positions on the left (channels 16, 17, 25, 33, and 34) and right (channels 9, 10, 18, 26, and 27) dorsolateral prefrontal cortex and the prefrontal area near the frontopolar area (channels 13, 21, 22, and 30), based on an anatomic craniocerebral correlation study (Figure 2A).21 Changes in oxygenated hemoglobin have been postulated as the best indicator of blood oxygenation.22,23 Therefore, this study focused on the change in oxygenated hemoglobin concentration. NIRS data that clearly contained a motion artifact, which is determined by the minute observation about the theme was excluded from the statistical analyses. In addition, a low-pass filter equipped with a 0.1 Hz high cutoff was used to exclude any short-term motion artifacts from the data used for analysis. The mean oxygenated hemoglobin concentration during the 60-second verbal fluency task was calculated and the pre-task baseline was calculated using the mean of the last 10 seconds of the 30-second pre-task period.10 The change in oxygenated hemoglobin concentration during the verbal fluency task was calculated by subtracting the oxygenated hemoglobin concentration during the task period from the pre-task baseline oxygenated hemoglobin concentration. A z-score was calculated as follows: d = (m1 – m2)/s, where m1 and m2 represent the mean concentration values during the baseline and trial, respectively, and s represents the standard deviation of the baseline. In order to increase the signal-to-noise ratio, z-scores were calculated from 14 channels within each measurement domain. We then compared each of the two groups using Student’s t-test, and the significance level in the analysis was set to P = 0.05. Since we performed 14 paired t-tests, the correction for multiple comparisons was made using the false discovery rate (two-tailed; we set the value of q specifying the maximum false discovery rate to 0.05, so that there are no more than 5% false positives on average). All statistical analyses were performed using Statistical Package for the Social Sciences version 17.0 J for Windows software (IBM, Armonk, NY, USA).


Reduced dorsolateral prefrontal cortical hemodynamic response in adult obsessive-compulsive disorder as measured by near-infrared spectroscopy during the verbal fluency task.

Hirosawa R, Narumoto J, Sakai Y, Nishida S, Ishida T, Nakamae T, Takei Y, Fukui K - Neuropsychiatr Dis Treat (2013)

Localization matrices mapped over a standard brain template. Areas shown in yellow represent matrix of guidance channels. (A) Matrix of guidance in which areas shown in orange represent regions of interest. (B) Patients with obsessive-compulsive disorder had significantly smaller changes in oxygenated hemoglobin concentration than controls at channel 18 (orange), localized near the right lateral prefrontal region.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3713899&req=5

f2-ndt-9-955: Localization matrices mapped over a standard brain template. Areas shown in yellow represent matrix of guidance channels. (A) Matrix of guidance in which areas shown in orange represent regions of interest. (B) Patients with obsessive-compulsive disorder had significantly smaller changes in oxygenated hemoglobin concentration than controls at channel 18 (orange), localized near the right lateral prefrontal region.
Mentions: First, changes in the oxygenated hemoglobin concentration in each of the 14 channels were analyzed. Channel groupings corresponded to approximate positions on the left (channels 16, 17, 25, 33, and 34) and right (channels 9, 10, 18, 26, and 27) dorsolateral prefrontal cortex and the prefrontal area near the frontopolar area (channels 13, 21, 22, and 30), based on an anatomic craniocerebral correlation study (Figure 2A).21 Changes in oxygenated hemoglobin have been postulated as the best indicator of blood oxygenation.22,23 Therefore, this study focused on the change in oxygenated hemoglobin concentration. NIRS data that clearly contained a motion artifact, which is determined by the minute observation about the theme was excluded from the statistical analyses. In addition, a low-pass filter equipped with a 0.1 Hz high cutoff was used to exclude any short-term motion artifacts from the data used for analysis. The mean oxygenated hemoglobin concentration during the 60-second verbal fluency task was calculated and the pre-task baseline was calculated using the mean of the last 10 seconds of the 30-second pre-task period.10 The change in oxygenated hemoglobin concentration during the verbal fluency task was calculated by subtracting the oxygenated hemoglobin concentration during the task period from the pre-task baseline oxygenated hemoglobin concentration. A z-score was calculated as follows: d = (m1 – m2)/s, where m1 and m2 represent the mean concentration values during the baseline and trial, respectively, and s represents the standard deviation of the baseline. In order to increase the signal-to-noise ratio, z-scores were calculated from 14 channels within each measurement domain. We then compared each of the two groups using Student’s t-test, and the significance level in the analysis was set to P = 0.05. Since we performed 14 paired t-tests, the correction for multiple comparisons was made using the false discovery rate (two-tailed; we set the value of q specifying the maximum false discovery rate to 0.05, so that there are no more than 5% false positives on average). All statistical analyses were performed using Statistical Package for the Social Sciences version 17.0 J for Windows software (IBM, Armonk, NY, USA).

Bottom Line: Z-scores for changes in the concentration of oxygenated hemoglobin were compared between the OCD patients and controls in 14 channels set over the left and right dorsolateral prefrontal cortex and frontopolar areas.During the verbal fluency task, significant task-related activation was detected in both the OCD group and the controls.Changes in oxygenated hemoglobin concentration in the right dorsolateral prefrontal cortex were significantly smaller in the OCD group than in the controls, but were not statistically significant after correction for multiple comparisons.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto.

ABSTRACT

Background: Near-infrared spectroscopy has helped our understanding of the neurobiological mechanisms of psychiatric disorders and has advantages including noninvasiveness, lower cost, and ease of use compared with other imaging techniques, like functional magnetic resonance imaging. The verbal fluency task is the most common and well established task used to assess cognitive activation during near-infrared spectroscopy. Recent functional neuroimaging studies have shown that the orbitofrontal cortex and other brain regions, including the dorsolateral prefrontal cortex, may play important roles in the pathophysiology of obsessive-compulsive disorder (OCD). This study aimed to evaluate hemodynamic responses in the dorsolateral prefrontal cortex in patients with OCD using near-infrared spectroscopy during the verbal fluency task and to compare these with dorsolateral prefrontal cortex responses in healthy controls.

Methods: Twenty patients with OCD and 20 controls matched for age, gender, handedness, and estimated intelligence quotient participated in this study. The verbal fluency task was used to elicit near-infrared spectroscopic activation and consisted of a 30-second pre-task, followed by three repetitions of a 20-second verbal fluency task (total 60 seconds), followed by a 70-second post-task period. The near-infrared spectroscopy experiment was conducted on the same day as surveys of obsessive-compulsive symptoms, depression, and anxiety. Z-scores for changes in the concentration of oxygenated hemoglobin were compared between the OCD patients and controls in 14 channels set over the left and right dorsolateral prefrontal cortex and frontopolar areas.

Results: During the verbal fluency task, significant task-related activation was detected in both the OCD group and the controls. Changes in oxygenated hemoglobin concentration in the right dorsolateral prefrontal cortex were significantly smaller in the OCD group than in the controls, but were not statistically significant after correction for multiple comparisons.

Conclusion: Patients with OCD have reduced prefrontal, especially right dorsolateral prefrontal, cortical hemodynamic responses as measured by near-infrared spectroscopy during the verbal fluency task. These results support the hypothesis that the dorsolateral prefrontal cortex plays a role in the pathophysiology of OCD.

No MeSH data available.


Related in: MedlinePlus