Cognitive performance, mood and experimental pain before and during morphine-induced analgesia in patients with chronic non-malignant pain

Abstract

This paper investigates subjective, behavioral and neurophysiological changes due to treatment with oral sustained-release morphine in six patients with severe non-malignant pain. Patients rated their mood and clinical pain on visual analog scales (VAS). Experimental pain reactions were quantified by ratings on categorical scales and evoked cerebral potentials (LEP) in response to standardized laser stimuli. A standard auditory oddball task provided reaction time (RT), errors, N1 and P2 of late auditory evoked potentials (AEP), and a P300 component. It was used to measure vigilance and cognitive performance. In parallel with clinical pain reduction, laser pain ratings and LEP amplitudes were significantly reduced. In contrast, auditory P2 and P300 amplitude were found to be even enlarged under morphine. RT and mood also failed to indicate any sedation. It is concluded that LEP indicated the analgesic morphine effects whereas late potentials and P300 from auditory stimuli reflected the perceptual-cognitive status which, instead of being deteriorated by morphine-induced sedation, improved probably due to the removal of pain as a mental stressor.

Attentional functioning in fibromyalgia, rheumatoid arthritis, and musculoskeletal pain patients

“…The RA and FM groups reported greater use of opioid medications compared with the MSK group. However, although a variety of medications, including opioids, are known to affect cognitive function, recent data have shown that attentional functioning is either not disrupted or improves in individuals, including chronic pain patients, following opioid consumption using both performance and electrophysiological measures (17)(18)(19)(20)(21)(22). In our study, patients who received opioid medications did not perform significantly differently from patients who did not receive opioids.…”

Are all Older Adults with Persistent Pain Created Equal? Preliminary Evidence for a Multiaxial Taxonomy

“…Preliminary data suggest that pain per se leads to postoperative cognitive dysfunction in older adults (67,68). Laboratory studies performed on young and middle-aged individuals with persistent pain demonstrate that pain intensity is inversely associated with successful completion of attention-demanding tasks (28)(29)(30), and that effective use of opioid analgesics may improve cognitive status (69). These studies lend strong support to the hypothesis that pain directly impairs attention and concentration, rather than that depression acts as the mediating factor, as some investigators have suggested (70).…”

Effective Treatment of Chronic Low Back Pain in Humans Reverses Abnormal Brain Anatomy and Function

“…There is evidence that some people with chronic pain also have cognitive impairment (Kewman et al, 1991;Eccleston, 1995;Lorenz et al, 1997;Park et al, 2001;Dick et al, 2002Dick et al, , 2003Apkarian et al, 2004a;Harman and Ruyak, 2005;Veldhuijzen et al, 2006;Lee et al, 2010). Findings from a recent study in healthy individuals suggested that this cognitive impairment could be a result of the demands that pain puts on cognitive brain networks: cognitive load-related activity was enhanced by pain, and even pain alone activated this cognitive network (Seminowicz and Davis, 2007b).…”