Contributions
Abstract: P1064
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Experimental models
Introduction: The underlying mechanisms of cognitive fatigue in multiple sclerosis (MS) are poorly understood. The majority of studies in MS fatigue focus around the reward system. However, new evidence supports the role of the interoceptive system in MS fatigue and chronic fatigue syndrome. Interoception refers to the axis conveying information from the internal body to the brain. Different brain processes underlie different interoceptive dimensions: bottom-up neural pathways are related to interoceptive accuracy (performance on objective behavioural tests of heartbeat tracking); top-down neural pathways are related to interoceptive awareness (confidence-accuracy correspondence). Stephan et al proposed fatigue to be a result of sequential responses to the interoceptive experience of dyshomeostasis, therefore an impairment of top-down neural processing.
Objectives: Our objective was to test the hypothesis that in MS fatigue top-down processes are impaired. Hence, we expected lower interoceptive awareness in fatigued (F) compared to non-fatigued (NF) MS patients, but no difference in interoceptive accuracy.
Methods: Sixty-eight MS participants were divided into F and NF groups using the cognitive domain of the Modified Fatigue Impact Scale (MFISc). The groups were matched for age, gender, education, disease duration and disease modifying treatment effectiveness. Participants performed a heartbeat tracking task, measuring interoceptive accuracy and awareness. MRI data were acquired: multi-shell diffusion magnetic resonance for neurite orientation dispersion and density imaging, quantitative magnetization transfer (which is sensitive to myelin), cutting edge multi-echo resting-state functional MRI , for assessing functional connectivity among interoceptive nodes.
Results: The cohort had low disability (median Expanded Disability Status Scale EDSS of 1.5).The F group had a significantly (p=0.001) higher disability (median EDSS of 2.75 in the F compared to 1.25 in the NF group). Interoceptive awareness was inversely correlated to cognitive fatigue levels (r=-0.304, p=0.012). Interoceptive accuracy was not correlated to cognitive fatigue.
Conclusion: This is the first study looking at the role of interoception in MS fatigue, using both behavioral and MRI data. Interoceptive awareness but not accuracy impaired in fatigued MS patients supports the top-down hypothesis of MS fatigue. The hypothesis will be further tested by MRI data analysis.
Disclosure: Dr Bogdan has received travel bursaries from Biogen and Merk. Dr Rashid has received travel bursaries and speaking fees from Biogen, Merk, Novartis, Sanofi-Genzyme and Roche. Prof Mara Cercignani: nothing to disclose. Dr Charlotte Rae: nothing to disclose.
Abstract: P1064
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Experimental models
Introduction: The underlying mechanisms of cognitive fatigue in multiple sclerosis (MS) are poorly understood. The majority of studies in MS fatigue focus around the reward system. However, new evidence supports the role of the interoceptive system in MS fatigue and chronic fatigue syndrome. Interoception refers to the axis conveying information from the internal body to the brain. Different brain processes underlie different interoceptive dimensions: bottom-up neural pathways are related to interoceptive accuracy (performance on objective behavioural tests of heartbeat tracking); top-down neural pathways are related to interoceptive awareness (confidence-accuracy correspondence). Stephan et al proposed fatigue to be a result of sequential responses to the interoceptive experience of dyshomeostasis, therefore an impairment of top-down neural processing.
Objectives: Our objective was to test the hypothesis that in MS fatigue top-down processes are impaired. Hence, we expected lower interoceptive awareness in fatigued (F) compared to non-fatigued (NF) MS patients, but no difference in interoceptive accuracy.
Methods: Sixty-eight MS participants were divided into F and NF groups using the cognitive domain of the Modified Fatigue Impact Scale (MFISc). The groups were matched for age, gender, education, disease duration and disease modifying treatment effectiveness. Participants performed a heartbeat tracking task, measuring interoceptive accuracy and awareness. MRI data were acquired: multi-shell diffusion magnetic resonance for neurite orientation dispersion and density imaging, quantitative magnetization transfer (which is sensitive to myelin), cutting edge multi-echo resting-state functional MRI , for assessing functional connectivity among interoceptive nodes.
Results: The cohort had low disability (median Expanded Disability Status Scale EDSS of 1.5).The F group had a significantly (p=0.001) higher disability (median EDSS of 2.75 in the F compared to 1.25 in the NF group). Interoceptive awareness was inversely correlated to cognitive fatigue levels (r=-0.304, p=0.012). Interoceptive accuracy was not correlated to cognitive fatigue.
Conclusion: This is the first study looking at the role of interoception in MS fatigue, using both behavioral and MRI data. Interoceptive awareness but not accuracy impaired in fatigued MS patients supports the top-down hypothesis of MS fatigue. The hypothesis will be further tested by MRI data analysis.
Disclosure: Dr Bogdan has received travel bursaries from Biogen and Merk. Dr Rashid has received travel bursaries and speaking fees from Biogen, Merk, Novartis, Sanofi-Genzyme and Roche. Prof Mara Cercignani: nothing to disclose. Dr Charlotte Rae: nothing to disclose.