Cold Pressor-Induced Pain Does Not Impair WAIS-IV Processing Speed Index or Working Memory Index Performance

Abstract

Chronic pain frequently involves cognitive complaints such as concentration and memory deficits, but studies of the effects of pain on cognition have not consistently demonstrated deficits and have not typically utilized standard neuropsychological instruments. Effects of cold pressor-induced pain on Wechsler Adult Intelligence Scale-Fourth Edition Processing Speed Index (PSI) and Working Memory Index (WMI) performance was examined in nonclinical volunteers (n = 40). All took one PSI subtest and one WMI subtest normally, and then took different PSI and WMI subtests during cold pressor-induced pain or painless warm-water immersion. Scaled scores for normal administration versus pain or painless water immersion did not differ and there was no interaction between group (control vs. pain) and manner of administration, despite moderately severe mean pain ratings (M = 6.8 on a 0–10 pain-rating scale). Results indicate that induced pain in nonclinical volunteers does not impair PSI or WMI performance, and they suggest that chronic pain per se should not be expected to substantially affect these cognitive functions. However, patients with chronic pain may differ from nonclinical volunteers in their experience of pain, potentially limiting generalizability.

Key words:

• assessment
• chronic pain
• Wechsler Adult Intelligence Scale

ACKNOWLEDGEMENTS

I am grateful to research assistants Claire Allen, Rebecca Cormier, Nicolle Cumley, Laura Pacheco, and Arianna Skinner-Barney, whose efforts were essential in completing this study.

Notes

¹This approach was suggested by Bradley Axelrod, and refined with advice from Alex Nagurney.

n = 20 per condition.

^a F = female; M = male.

^b Ethnicity: AA = African American; H = Hispanic; M = Mixed; W = White.

^c Handedness: R = right-handed; L = left-handed.

^a Pain ratings were averaged across subtest administration and were based on a 0-to-10 scale where 0 represented no pain.