Investigation on how dynamic effective connectivity patterns encode the fluctuating pain intensity in chronic migraine
Source : https://www.sciencedirect.com/science/article/pii/S2452073X22000174?via=ihub
Chronic migraine is characterised by persistent headaches for >15 days per month; the intensity of the pain is fluctuating over time. Here, we explored the dynamic interplay of connectivity patterns between regions known to be related to pain processing and their relation to the ongoing dynamic pain experience.
Conclusion/Relevance: The results reflect the multi-facetted clinical picture of the disease. Across all sessions, each patient with chronic migraine exhibited a distinct pattern of pain intensity-related cortical connectivity. The diversity of the individual findings are accompanied by inconsistent relations between the connectivity parameters and pain intensity or pain intensity changes at group level. This suggests a rejection of the idea of a common neuronal core problem for chronic migraine.
• Source: Neurobiology of Pain
• Conclusion: “This study was a first step to gain insight into relations between fluctuating connectivity and the almost daily headaches that CM patients experience … The results reflect the multi-facetted clinical picture of the disease. Across all sessions, each patient with chronic migraine exhibited a distinct pattern of pain intensity-related cortical connectivity. The diversity of the individual findings are accompanied by inconsistent relations between the connectivity parameters and pain intensity or pain intensity changes at group level. This suggests a rejection of the idea of a common neuronal core problem for chronic migraine.”
• In the current study, researchers from Belgium and Germany analyzed the interplay of connectivity patterns in regions that are tied to pain processing, as well as the relation to ongoing pain. EEGs were taken from 80 session (20 patients with chronic migraine in 4 sessions). Patients constantly rated headache intensity.
• The researcher found that for each patient/session, “The evolving dynamics of effective connectivity were related to pain intensities and to pain intensity changes by using a Bayesian linear model.”
• Based on their results, the researchers reject the hypothesis that a common neuronal core mediates chronic migraine.
• The authors suggest that individual patients harbor specific patterns of brain dynamics that underlie chronic pain and capturing this complaint is difficult. Neuroimaging on a group level may not identify a pain-intensity biomarker.
• They wrote, “Finding the appropriate neuroimaging method and analysis to establish brain markers that are stable throughout multiple recording sessions of the same patient may be the way forward to guide individualised treatments.”
• Limitations of the study include the researchers failing to pick the right network for pain processing in chronic migraine, and not using the right model to capture dynamically evolving pain-related oscillations. Additionally, the design of the current study precludes the inclusion of a control group.