A particular effect of sleep, but not pain or depression, on the blood-oxygen-level dependent response during working memory tasks in patients with chronic pain

Clinical pain, abstraction, and self-control: being in pain makes it harder to see the forest for the trees and is associated with lower self-control

OBJECTIVES

Although abstract thinking is a fundamental dimension of human cognition, it has received scant attention in research on pain and cognition. We hypothesized that physical pain impairs abstraction, because when people experience pain at high intensity levels, attention becomes concretely focused on the self in the here and now, where little else matters than finding relief for the pain they are currently experiencing. We also examined the relationship between pain and self-control, predicting that pain would debilitate self-control.

PATIENTS AND METHODS

Abstraction and self-reported self-control were assessed in 109 patients with musculoskeletal pain. The influence of specific pain qualities, such as pain intensity, pain interference with daily activities, pain duration, and pain persistence, was examined. Furthermore, we assessed other factors (e.g., anxiety, depression, and fatigue) that could be assumed to play a role in the pain experience and in cognitive performance.

RESULTS

Higher pain intensity and persistence were associated with less abstract thinking. Furthermore, self-control decreased with greater pain intensity, persistence, and self-reported pain interference with daily activities. Self-reported depressive symptoms mediated the overall relationship between pain and self-control.

CONCLUSION

Abstraction is compromised in patients reporting higher pain intensity and persistence. Different dimensions of pain also predict lower self-control although depression seems to account for the relationship between overall pain and self-control. The current study is the first to report an association between clinical musculoskeletal pain and abstraction. The results suggest that pain patients may suffer from a broader range of cognitive disadvantages than previously believed.

The Effect of Insomnia on Neuropsychological Functioning in Patients with Comorbid Symptoms of Pain, Fatigue, and Mood Disorders

OBJECTIVES

To examine if elevated symptoms of insomnia affects neuropsychological functioning in patients with concurrent symptoms of pain, fatigue, and mood disorders.

METHODS AND RESULTS

A total of seventy-six subjects participated in this (cross-sectional) study. Based on the cut-off score guidelines from The Insomnia Severity Index subjects were assigned to either a clinical insomnia group (N = 35) or a comparison group (N = 41). Factors such as age, general cognitive functioning, and symptoms of pain, fatigue, depression, and anxiety did not differ between the groups. Both groups completed a questionnaire which assessed subjective memory functioning. In addition they completed a set of neuropsychological tests measuring general cognitive functioning, spatial and verbal working memory, and inhibitory control. Although the subjects with clinical insomnia did not report more memory problems than the comparison group, they presented significant deficiencies on the tests assessing spatial and verbal working memory. There was no difference between the groups in inhibitory control.

CONCLUSIONS

This study shows that as the symptom severity of insomnia increases and become clinically significant, it has substantial effect on both spatial and verbal-numeric working memory functioning. By differentiating and testing different domains of working memory, this study provides a more detailed and nuanced characterization of working memory deficiencies than the previous studies within this field. The results need to be transferred to clinical practice so that neuropsychologists include assessments of sleep as part of their routine screenings.

Cognitive deficits associated with impaired awareness of hypoglycaemia in type 1 diabetes

AIMS/HYPOTHESIS

The aim of this study was to compare cognitive function in adults with type 1 diabetes who have impaired awareness of hypoglycaemia with those who have normal awareness of hypoglycaemia. A putative association was sought between cognitive test scores and a history of severe hypoglycaemia.

METHODS

A total of 68 adults with type 1 diabetes were included: 33 had impaired and 35 had normal awareness of hypoglycaemia, as confirmed by formal testing. The groups were matched for age, sex and diabetes duration. Cognitive tests of verbal memory, object-location memory, pattern separation, executive function, working memory and processing speed were administered.

RESULTS

Participants with impaired awareness of hypoglycaemia scored significantly lower on the verbal and object-location memory tests and on the pattern separation test (Cohen's d -0.86 to -0.55 [95% CI -1.39, -0.05]). Participants with impaired awareness of hypoglycaemia had reduced planning ability task scores, although the difference was not statistically significant (Cohen's d 0.57 [95% CI 0, 1.14]). Frequency of exposure to severe hypoglycaemia correlated with the number of cognitive tests that had not been performed according to instructions.

CONCLUSIONS/INTERPRETATION

Impaired awareness of hypoglycaemia was associated with diminished learning, memory and pattern separation. These cognitive tasks all depend on the hippocampus, which is vulnerable to neuroglycopenia. The findings suggest that hypoglycaemia contributes to the observed correlation between impaired awareness of hypoglycaemia and impaired cognition.

Impaired psychomotor ability and attention in patients with persistent pain: a cross-sectional comparative study

Background and aims

Patients with pain have shown cognitive impairment across various domains. Although the pain qualities vary among patients, research has overlooked how cognitive performance is affected by the duration and persistence of pain. The current study sought to fill this gap by examining how qualitatively different pain states relate to the following cognitive functions: sustained attention, cognitive control, and psychomotor ability.

Patients and methods

Patients with musculoskeletal pain in primary care were divided into three pain groups: acute pain (duration <3 months), regularly recurrent pain (duration >3 months), and persistent pain (duration >3 months). These groups were then compared with healthy controls. The MapCog Spectra Test, the Color Word Test, and the Grooved Pegboard Test were used to measure sustained attention, cognitive control, and psychomotor ability, respectively.

Results

Patients with persistent pain showed significantly worse sustained attention and psychomotor ability compared with healthy controls. The acute pain group showed a significant decrease in psychomotor ability, and the regularly recurrent pain group showed a significant decrease in sustained attention. These results remained unchanged when age, education, and medication were taken into account.

Conclusion

Persistent musculoskeletal pain seems to impair performance on a wider range of cognitive tasks than acute or regularly recurrent pain, using pain-free individuals as a benchmark. However, there is some evidence of impairment in psychomotor ability among patients with acute pain and some impairment in sustained attention among patients with regularly recurrent pain.

Implications

Caregivers may need to adjust communication methods when delivering information to cognitively impaired patients.