title: Quantitative sensory testing and pain tolerance in patients with mild to moderate Alzheimer disease compared to healthy control subjects.
abstract: Patients with Alzheimer disease (AD) report pain less frequently than their cognitively intact peers. It has been hypothesized that pain processing is altered in AD. The aim of this study was to investigate agreement and reliability of 3 pain sensitivity tests and to examine pain threshold and tolerance in patients with AD. We examined 29 patients with mild to moderate AD and 29 age- and gender-matched healthy control subjects with quantitative sensory testing, ie, assessments of detection threshold (warmth detection threshold [WDT]) and pain threshold (heat pain threshold [HPT], pressure algometry, cold pressor test), and assessments of tolerance (pressure algometry, cold pressor test). All procedures were done twice on day 1, 1 hour apart, and repeated on day 2. We found no difference between groups for WDT (patient vs control subjects: mean [95% confidence interval]: 35.5°C [33.4°C to 37.6°C] vs 35.4°C [34.3°C to 36.5°C], P=.8) or HPT (41.2°C [40.0°C to 42.4°C] vs 42.3°C [41.1°C to 43.5°C], P=.24). We observed comparable thresholds for pressure algometry (median [25% to 75% interquartile range]: 120 kPa [100 to 142 kPa] vs 131 kPa [113 to 192 kPa], P=.10), but significantly lower tolerance in AD patients (213 kPa [188 to 306 kPa] vs 289 kPa [262 to 360 kPa], P=.008). No differences were found for the cold pressor test. The study demonstrated good replicability of the sensory testing data with comparable data variability, for both groups, which supports the use of these methods in studies of patients with mild to moderate AD. Contrary to previous studies, we observed a reduced pain tolerance in patients with mild to moderate AD, which suggests that the reduced report of pain cannot be explained by reduced processing of painful stimuli.
authors.affiliation: Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Denmark Multidisciplinary Pain Center, Neuroscience Center, Rigshospitalet, Copenhagen University Hospital, Denmark Department of Anaesthesia, Rigshospitalet, Copenhagen University Hospital, Denmark Danish Pain Research Center, Department of Neurology, Aarhus University Hospital, Denmark Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen University Hospital, Denmark.
authors.forename: Christina
authors.initials: C
authors.lastname: Jensen-Dahm
authors.forename: Mads U
authors.initials: MU
authors.lastname: Werner
authors.forename: Jørgen B
authors.initials: JB
authors.lastname: Dahl
authors.forename: Troels Staehelin
authors.initials: TS
authors.lastname: Jensen
authors.forename: Martin
authors.initials: M
authors.lastname: Ballegaard
authors.forename: Anne-Mette
authors.initials: AM
authors.lastname: Hejl
authors.forename: Gunhild
authors.initials: G
authors.lastname: Waldemar
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000503:physiopathology*; D003080:Cold Temperature; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D012720:Severity of Illness Index
keywords: Alzheimer disease; Cold pressor test; Dementia; Elderly; Pain; Quantitative sensory testing