The Reliability of Algometry in the Assessment of Patients with Fibromyalgia Syndrome

SUMMARY

Objectives: The purpose of this review is to document the utility and reliability of quantitative body tenderness examination in fibromyalgia syndrome [FMS] by two methods: digital pressure tender point index [TPI], and average pain threshold [APT] by algometry.

Findings: Body tenderness in people with musculoskeletal pain has been recognized for over 500 years. Current criteria for the diagnosis of FMS are based on chronic widespread pain and pain induced by digital palpation at 11 or more of 18 anatomically defined tender point [TP] sites. The relative reliabilities of TPI and APT as measures of severity have been confirmed. Inter-rater and intra-rater, test-retest reliability assessments for paired examinations have shown that both APT and TPI were highly reliable but that APT has been marginally superior. Some self-report measures of FMS subjects, such as visual analog scales [for pain, insomnia, headache, stiffness] and several questionnaires [for disability, anxiety, depression] correlate with tenderness while others do not. Both TPI and APT have correlated with pain, stiffness and disability but TPI also correlated with anxiety, and depression.

Conclusions: Both TPI and APT are highly reliable as semi-objective measures to document tenderness severity in FMS patients. They exhibit slightly different conceptual constructs in that APT appears to be less influenced by psychological factors than the TPI. These findings highlight the usefulness of combining subjective and semi-objective measures in the routine clinical [and research outcome] assessment of people with FMS.

KEYWORDS:

• Fibromyalgia syndrome
• tender point index
• algometry
• validation
• review