European journal of pain : EJP
-
Growing evidence indicates a link between changes in the medial prefrontal cortex and the pathophysiology of chronic pain. In particular, chronic pain is associated with altered medial prefrontal anatomy and biochemistry. Due to the comorbid affective disorders seen across all pain conditions, the medial prefrontal cortex is a region of significance as it is involved in emotional processing. We have recently reported that a decrease in medial prefrontal N-acetylaspartate and glutamate is associated with increased emotional dysregulation, indicating there are neurotransmitter imbalances in chronic pain. Therefore, we compared medial prefrontal neurochemistry in 24 people with chronic pain conditions to 24 age and sex-matched healthy controls with no history of chronic pain. ⋯ This study reveals a significant reduction in γ-aminobutyric acid (GABA+ ) and glutamate within the medial prefrontal cortex in chronic pain sufferers. While the current findings should be considered with reference to a small sample size, the disruption to normal excitatory and inhibitory medial prefrontal cortex function may be key in the development and maintenance of chronic pain and comorbid mental health disorders.
-
Recent evidence suggests that pain dampens attentional processes. However, much of this work has been based on higher-order attentional tasks that involve only spatial attention. Other aspects of the process through which pain engages and holds attention are relatively understudied, in particular, temporal attention. The present set of studies explored how naturally occurring pain (i.e. acute headache) and pain-valenced stimuli affect the ability to recall the second of two targets presented in rapid succession. ⋯ Pain captures attention to allow cognate resources to be directed appropriately in response. However, the temporal effects of this attentional capture are poorly understood. Findings indicate that acute headache pain has a negative impact on participants' performance when identifying the second of two targets presented in close temporal proximity, and that pain-valenced stimuli exacerbate this effect. These findings demonstrate how pain affects early attention and highlights the potential role of disengagement, rather than orientation, of attention in the pain experience.
-
Complex regional pain syndrome (CRPS) is a debilitating pain condition often resistant to standard treatment modalities. In these cases, spinal cord stimulation (SCS) can be an option, but the effect on CRPS remains disputed. We aimed to assess the long-term effect of SCS on CRPS. ⋯ This study presents detailed data from a large, well-characterized cohort of Danish CRPS patients treated with SCS, analyzing several outcome measures. The results serve to document SCS as an effective treatment for severe CRPS and expands the cumulative level of evidence in favor of its use. Additionally, analysis of preoperative patient characteristics suggests that SCS treatment should not be withheld in patients with a high degree of psychological distress or high consumption of analgesics.
-
Reduced laser-evoked potential (LEP) habituation indicates abnormal central pain processing. But the paradigm (four stimulation blocks a 25 stimuli) is time consuming and potentially omits important information on the exact habituation time course. This study examined whether a high temporal resolution (HTR) analysis (dividing the four stimulation blocks into 12 analysis blocks) can answer the following questions: (a) After how many stimuli does LEP habituation occur? (b) Is there a difference in LEP habituation in younger versus older subjects? (c) Is HTR applicable on radiculopathy patients? ⋯ The usage of high temporal resolution (HTR) analysis in young healthy subjects enables a short test protocol and provides the exact time course of laser-evoked potential habituation. This can be useful for the examination of neurological conditions affecting younger patients and for pharmacological studies. HTR was inapplicable in advanced-aged subjects and patients with radiculopathy.