title: Test-retest reliability of thermal temporal summation using an individualized protocol.
abstract: Temporal summation (TS) refers to the increased perception of pain with repetitive noxious stimuli. It is a behavioral correlate of wind-up, the spinal facilitation of recurring C-fiber stimulation. In order to utilize TS in clinical pain research, it is important to characterize TS in a wide range of individuals and to establish its test-retest reliability. Building on a fixed-parameter protocol, we developed an individually adjusted protocol to broadly capture thermally generated TS. We then examined the test-retest reliability of TS within-day (intertrial intervals ranging from 2 to 30 minutes) and between-days (intersession interval of 7 days). We generated TS-like effects in 19 of the 21 participants. Strong correlations were observed across all trials over both days (intraclass correlation [ICC] [A, 10] = .97, 95% confidence level [CL] = .94-.99) and across the initial trials between days (ICC [A, 1] = .83, 95% CL = .58-.93). Repeated measures mixed-effects modeling demonstrated no significant within-day variation and only a small (5 out of 100 points) between-day variation. Finally, a Bland-Altman analysis suggested that TS is reliable across the range of observed scores. Without intervention, thermally-generated TS is generally stable within day and between days.
  
  
  CONCLUSIONS
  Our study introduces a new strategy to generate thermal TS in a high proportion of individuals. This study confirms the test-retest reliability of thermal TS, supporting its use as a consistent behavioral correlate of central nociceptive facilitation.
authors.affiliation: Department of Anesthesia, Division of Pain Medicine, Stanford Neuroscience and Pain Laboratory, Stanford University, Palo Alto, California 94304, USA.
authors.forename: Jiang-Ti
authors.initials: JT
authors.lastname: Kong
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Johnson
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Balise
authors.forename: Sean
authors.initials: S
authors.lastname: Mackey
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D003627:Data Interpretation, Statistical; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000523:psychology*; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology*; D015203:Reproducibility of Results; D055815:Young Adult