Pengmin Qin1,2,3, Xuehai Wu4, Niall W Duncan1,2,3,5, Weiqi Bao6, Weijun Tang7, Zhengwei Zhang6, Jin Hu4, Yi Jin4, Xing Wu4, Liang Gao4, Lu Lu8, Yihui Guan6, Timothy Lane2,3, Zirui Huang2, Yelena G Bodien9, Joseph T Giacino9, Ying Mao4, Georg Northoff1,2,3,5,10. 1. Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan. 2. Institute of Mental Health Research, University of Ottawa, Ottawa, Canada. 3. Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan. 4. Neurosurgery Department, Huashan Hospital, Fudan University, Shanghai, China. 5. Centre for Cognition and Brain Disorders (CCBD), Hangzhou Normal University, Hangzhou, China. 6. PET/CT Centre, Huashan Hospital, Fudan University, Shanghai, China. 7. Radiologic Department of Huashan Hospital, Fudan University, Shanghai, China. 8. Antai Hospital, Shanghai, China. 9. Spaulding Rehabilitation Hospital, Charlestown, Massachusetts. 10. Research Centre for Mind, Brain and Learning, National Chengchi University, Taipei, Taiwan.
Abstract
OBJECTIVES: Disorders of consciousness (DoC)-that is, unresponsive wakefulness syndrome/vegetative state and minimally conscious state-are debilitating conditions for which no reliable markers of consciousness recovery have yet been identified. Evidence points to the GABAergic system being altered in DoC, making it a potential target as such a marker. EXPERIMENTAL DESIGN: In our preliminary study, we used [(11) C]Flumazenil positron emission tomography to establish global GABAA receptor binding potential values and the local-to-global (LTG) ratio of these for specific regions. These values were then compared between DoC patients and healthy controls. In addition, they were correlated with behavioral improvements for the patients between the time of scanning and 3 months later. Functional magnetic resonance imaging resting-state functional connectivity was also calculated and the same comparisons made. PRINCIPAL OBSERVATIONS: lobal GABAA receptor binding was reduced in DoC, as was the LTG ratio in specifically the supragenual anterior cingulate. Both of these measures correlated with behavioral improvement after 3 months. In contrast to these measures of GABAA receptor binding, functional connectivity did not correlate with behavioral improvement. CONCLUSIONS: Our preliminary findings point toward GABAA receptor binding being a marker of consciousness recovery in DoC.
OBJECTIVES: Disorders of consciousness (DoC)-that is, unresponsive wakefulness syndrome/vegetative state and minimally conscious state-are debilitating conditions for which no reliable markers of consciousness recovery have yet been identified. Evidence points to the GABAergic system being altered in DoC, making it a potential target as such a marker. EXPERIMENTAL DESIGN: In our preliminary study, we used [(11) C]Flumazenil positron emission tomography to establish global GABAA receptor binding potential values and the local-to-global (LTG) ratio of these for specific regions. These values were then compared between DoC patients and healthy controls. In addition, they were correlated with behavioral improvements for the patients between the time of scanning and 3 months later. Functional magnetic resonance imaging resting-state functional connectivity was also calculated and the same comparisons made. PRINCIPAL OBSERVATIONS: lobal GABAA receptor binding was reduced in DoC, as was the LTG ratio in specifically the supragenual anterior cingulate. Both of these measures correlated with behavioral improvement after 3 months. In contrast to these measures of GABAA receptor binding, functional connectivity did not correlate with behavioral improvement. CONCLUSIONS: Our preliminary findings point toward GABAA receptor binding being a marker of consciousness recovery in DoC.
Authors: Elina Salmi; Sargo Aalto; Jussi Hirvonen; Jaakko W Långsjö; Anu T Maksimow; Vesa Oikonen; Liisa Metsähonkala; Jussi Virkkala; Kjell Någren; Harry Scheinin Journal: Neuroimage Date: 2008-03-04 Impact factor: 6.556