TY - JOUR

T1 - Affective episodes in recently diagnosed patients with bipolar disorder associated with altered working memory-related prefrontal cortex activity

T2 - A longitudinal fMRI study

AU - Macoveanu, Julian

AU - Kjærstad, Hanne Lie

AU - Vinberg, Maj

AU - Harmer, Catherine

AU - Fisher, Patrick Mac Donald

AU - Knudsen, Gitte Moos

AU - Kessing, Lars Vedel

AU - Miskowiak, Kamilla Woznica

N1 - Publisher Copyright: © 2021

PY - 2021

Y1 - 2021

N2 - Introduction: Bipolar disorder (BD) is often accompanied by trait-related cognitive impairments, but it is unclear which neurocircuitry abnormalities give rise to these impairments and whether neurocircuitry differences are exacerbated with illness progression. This longitudinal fMRI study of recently diagnosed BD patients investigates whether aberrant working memory (WM) related activity in the cognitive control network is accentuated by new affective episodes. Methods: Forty-seven recently diagnosed BD patients in full or partial remission and 38 healthy controls were assessed with neurocognitive tests and fMRI during the performance of a verbal n-back WM task at baseline and follow-up (15.4 months in average). Results: Patients showed WM-related hypo-activity in dorsal prefrontal cortex (dPFC) and impaired cognitive function within attention and psychomotor speed, WM and executive function, and verbal learning and memory compared to controls at baseline. During the follow-up period, 26 patients experienced at least one affective episode (BD+), while 21 remained in remission (BD-). There was no deterioration in cognitive performance in BD+ compared to BD- patients. Nevertheless, BD+ displayed increased WM-related dPFC activity at follow-up compared with BD- patients. This change in dPFC response was independent of mood symptoms and medication. Limitations: The study did not account for type or frequency of affective episodes. Conclusion: The study identifies cognitive impairment and WM-related hypo-activity in dPFC early during the course of BD. Increased high-load WM related dPFC activity over the follow-up period in BD+ versus BD- patients in the absence of changes in cognitive performance may reflect an episode-related reduction in PFC efficiency.

AB - Introduction: Bipolar disorder (BD) is often accompanied by trait-related cognitive impairments, but it is unclear which neurocircuitry abnormalities give rise to these impairments and whether neurocircuitry differences are exacerbated with illness progression. This longitudinal fMRI study of recently diagnosed BD patients investigates whether aberrant working memory (WM) related activity in the cognitive control network is accentuated by new affective episodes. Methods: Forty-seven recently diagnosed BD patients in full or partial remission and 38 healthy controls were assessed with neurocognitive tests and fMRI during the performance of a verbal n-back WM task at baseline and follow-up (15.4 months in average). Results: Patients showed WM-related hypo-activity in dorsal prefrontal cortex (dPFC) and impaired cognitive function within attention and psychomotor speed, WM and executive function, and verbal learning and memory compared to controls at baseline. During the follow-up period, 26 patients experienced at least one affective episode (BD+), while 21 remained in remission (BD-). There was no deterioration in cognitive performance in BD+ compared to BD- patients. Nevertheless, BD+ displayed increased WM-related dPFC activity at follow-up compared with BD- patients. This change in dPFC response was independent of mood symptoms and medication. Limitations: The study did not account for type or frequency of affective episodes. Conclusion: The study identifies cognitive impairment and WM-related hypo-activity in dPFC early during the course of BD. Increased high-load WM related dPFC activity over the follow-up period in BD+ versus BD- patients in the absence of changes in cognitive performance may reflect an episode-related reduction in PFC efficiency.

KW - Bipolar disorder

KW - Cognitive impairment

KW - fMRI

KW - Prefrontal cortex

KW - Working memory

U2 - 10.1016/j.jad.2021.08.110

DO - 10.1016/j.jad.2021.08.110

M3 - Journal article

C2 - 34509780

AN - SCOPUS:85114685347

VL - 295

SP - 647

EP - 656

JO - Journal of Affective Disorders

JF - Journal of Affective Disorders

SN - 0165-0327

ER -