When did your pain start? Reliability of self-reported age of onset of facial pain

Objective: This study was designed to examine the reliability of self- reported onset of facial pain over a relatively long period, as well as factors that may influence the ability of patients to provide consistent pain onset dates. The implications of dating unreliability on assessing the temporal order of two potentially related disorders is also considered. Design: A total of 125 women with a lifetime history of temporomandibular pain and dysfunction syndrome (TMPDS) were asked to report their pain onset date in the con- text of a structured health interview. Dates were compared with onset dates recorded an average of 7 years earlier in their clinical chart. Factors potentially affecting reliability of recall were also assessed. Results: The absolute value of the discrepancy between the two reports was nearly years. Only 26% reported onset dates within the same year. Forward-telescoping, in which events are recalled as occurring more recently than they actually occurred, was more common than backward-telescoping of onset dates. Intraclass correlations were good to excellent (ICC =.80 for full sample). Elapsed time between reports was the largest predictor of reporting discrepancy. Conclusions: These findings indicate that a single patient's report of pain onset, especially when he or she is asked to recall the onset of a long-standing pain problem, will most often lead to an underestimate of chronicity. However, high intraclass correlations indicate that patients dating of pain onset may have satisfactory reliability for research purposes, when comparing a group of patients to one another to assess relative chronicity of pain.