Development of an objective portable measurement device for spinal joint accessory motion testing

Hsiao Kuan Wu, Hung Jen Lai, Ting Teng, Chung Huang Yu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Joint accessory motion testing (JAMT) is a standard procedure used by manual therapists to assess and treat musculoskeletal disorders. Joint accessory motion (JAM) is movement that occurs between joint surfaces, and can be induced by applying force. The motion amount, end feel, symptoms, and resistance perceived by therapists during test procedures are recorded as evidence for the diagnosis, prognosis, treatment decision making, and intervention outcome. However, previous studies have shown that accessory motion tests have insufficient reliability. Recently, many instruments have been developed to increase test reliability, but these instruments quantify the test results with a single probe and utilize the external environment as a reference. Therefore, the measured displacement amount may be affected by other spinal segments. This study proposes an objective portable measurement device with two indenter probes for spinal JAMT, wherein the JAM was quantified by displacement and force measurements between two bones. The instrument was verified with a homemade spinal simulator and computer simulation. The results showed that the force-displacement curves measured by the JAMT device (JAMTD) and those simulated by the computer model exhibited similar characteristics. Moreover, a two-probe measurement could distinguish the differences in stiffness better than a one-probe measurement.

Original languageEnglish
Article number100
JournalSensors (Switzerland)
Issue number1
StatePublished - 1 Jan 2020


  • Joint accessory motion test
  • Manual therapy
  • Spinal mobility
  • Spinal stiffness


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