Background & Aims
Chronic pain (CP) is a complex process involving sensory and emotional disturbances combined with behavioral adaptations. It is well-known that CP is significantly affected by lack of sleep and emotional alterations and vice versa. The disruptions in sleep together with CP affect brain homeostasis negatively, tilting the system toward neuroinflammation, which would reduce glymphatic clearance. In addition, CP can lead to gray matter reorganization in brain structures involved in emotional state and pain modulation. The periaqueductal gray(PAG) is one of the key structures that plays an important role in pain modulation. Moreover, PAG involves in disease states, including anxiety, panic disorders, depression and sleep disorders. Due to the high expression of aquaporins4, the PAG takes part in waste clearance in the brain. Based on the above, the aim of our study was to investigate MRI changes in PAG in the relationship with emotional disturbances and sleep disorders in patients with CP.
Methods
28 patients with chronic primary and secondary musculoskeletal pain (CP group) in the age range of 42-60 years and 20 age-match healthy individuals (control group) were tested using the Four-Dimensional Symptom Questionnaire (4DSQ) to assess distress, depression, anxiety and somatization, the Spiegel Sleep Questionnaire (SSQ) and the Visual Analogue Scale (VAS). Polysomnography with quantitative EEG spectral power analysis was used for sleep assessment. We used standardized MRI morphometry with manually segmented the PAG to assess its signal intensity. To assess the function of the glymphatic system, participants underwent diffusion tensor imaging analysis of the perivascular space (DTI-ALPS) with analysis of changes in the ALPS index.
Results
No differences were found between groups in terms of male to female ratio and age. CP group had a higher score on the 4DSQ total compared to control group (p< 0.001) as well as on distress, depression, anxiety and somatization subscales. CP patients had more severe subjective sleep disturbance according to the SSQ (p< 0.01), the total sleep time reduction (p< 0.005) and prolongation sleep onset latency (p = 0.01) compared to controls. Total slow-wave activity was significantly declined especially over frontal regions during NREM with an increase in ? band power over the parietal regions during REM sleep in patients with CP. MRI morphometry identified an increase PAG density in the CP group compared to controls (p< 0.01). The ALPS index in CP patients was lower than in controls and negatively correlated with the PAG density(p<0.01). PAG density had positive correlation with 4DSQ and VAS scores (p< 0.005) and negative correlation with the total sleep time and SSQ score (p< 0.01)
Conclusions
CP has close association with different pathological condition such as depression, anxiety, somatization and sleep problems. These conditions frequently co-occur leading to neurophysiological alterations as well as morphological reorganization of the brain. Reduction of the total slow-wave activity during NREM sleep decreases glymphatic clearance may offer a possible explanation for the relationship between sleep disorders and CP. Change the PAG density that has correlation with emotional alterations, pain severity and sleep parameters as well as ALPS index indicates that the PAG is a key brain structure that combines the main pathogenetic mechanisms of pain chronicity. In this regard, various effects on the PAG can be considered as one of the methods for treating primary and secondary musculoskeletal CP.
References
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Presenting Author
Alenikova Olga
Poster Authors
Olga Alenikova
MD, PhD
Republican Scientific and Clinical Center of Neurology and Neurosurgery
Lead Author
Ekaterina B?siakova
Republican Scientific and Clinical Center of Neurology and Neurosurgery
Lead Author
Lyudmila Parkhach
Republican Scientific and Clinical Center of Neurology and Neurosurgery
Lead Author
Dmitriy Antonenko,
Republican Scientific and Clinical Center of Neurology and Neurosurgery
Lead Author
Topics
- Pain Imaging