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College of Veterinary Medicine

Translational Research in Pain (TRiP) – Clinical Metrology Instruments

Clinical Metrology tools may be used for veterinary studies evaluating an intervention or treatment; translational studies using naturally occurring disease in animals as a model of human disease; clinical veterinary patient management.

Prior to using a tool, one must know that it reliably measures what it is purported to measure and that it is able to pick up clinically significant changes in the population in which it is being used.

The process of validation is thus an important one, and consists of several stages:

  • Item generation: The generation of the questions to be tested needs to be carefully undertaken, and have input from appropriate stakeholders.
    • Using patients (painful and healthy populations)
    • Using focus groups only
  • Readability: it is important the instrument can be easily understood by those using it (i.e. the target population)
  • Reliability: The stability of a tool examines the reproducibility of the tool administered on different occasions. When the tool is a questionnaire, its internal consistency is based on a single administration of the tool and represents the average of the correlations among the questions in the tool. Both internal consistency and stability must be proven before a questionnaire is to be deemed reliable.
    • Test – retest stability
    • Internal consistency
  • Validity
    • Face Validity: indicates whether, on the face of it, the tool appears to be assessing the desired qualities
    • Content Validity: a judgment regarding whether the tool covers all of the relevant content
    • Construct validity: Testing that is used when the tool is measuring something (a construct) that cannot be directly observed (pain, quality of life etc.). While the construct can not be directly seen, behaviors resulting from it can be observed. Obviously, it will be impossible to ‘prove’ that something that cannot be measured directly is being measured. Several approaches can be used:
      • Hypothesized factors tested with factor analysis
      • Discriminatory validity: Does the instrument discriminate between animals with and without the condition? Does it discriminate between different severities of the condition?
      • Responsiveness of the tool to a treatment known to change what is being measured, or to a change in the condition over time
      • Correlation to overall QoL
  • Criterion or Concurrent Validity: the correlation of an instrument with some other measure – a measure accepted as the ‘gold standard’. Often, in the development of subjective assessment tools, the best approach is to use an accepted objective measure. Because pain cannot (yet) be directly measured, an objective surrogate measure can be used, e.g. an objective measure of activity if pain is expected to impact activity

Metrology Instruments

Purpose:

The owner’s assessment of the severity of chronic pain in their cat, and the impact this has on everyday activity and interaction

Description and Characteristics:

The FMPI is a questionnaire with appropriate readability, reliability and proven discriminatory ability. Most recently, the instrument has been refined (FMPI short form – FMPIsf) and this has increased its responsiveness. Further validity testing is continuing, and further versions of the FMPI may well take place in the future.

Funding for Development:

The CPRL is very grateful to Morris Animal Foundation and to Novartis Animal Health for sponsoring the work that has led to the FMPI.

Further development of the FMPI has been possible through its use in studies funded by Boehringer Ingelheim Vetmedica, Nexvet Australia Pty Ltd and Elanco Animal Health. 

We are also grateful to Zoetis for their support in the recent refinement of the instrument.

Interested in a non-English version? Please send a message to dxlascel@ncsu.edu. We have French and Spanish versions available, and other languages coming soon.

References:

Enomoto M, Lascelles BDX, Gruen M. Refinement of the Feline Musculoskeletal Pain Index (FMPI) and Development of the Short Form FMPI. In press (2021), J Fel Med Surg

Adrian D, King JN, Parrish RS, King SB, S CB, Gruen ME, Lascelles BDX (2021) Robenacoxib shows efficacy for the treatment of chronic degenerative joint disease-associated pain in cats: a randomized and blinded pilot clinical trial. Sci Rep 11:7721.

Gruen ME, Thomson AE, Griffith EH, Paradise H, Gearing DP, Lascelles BD (2016) A Feline Specific Anti-Nerve Growth Factor Antibody Improves Mobility in Cats with Degenerative Joint Disease-Associated Pain: A Pilot Proof of Concept Study. J Vet Int Med 30:1138-1148.

Gruen ME, Griffith EH, Thomson AE, Simpson W, Lascelles BD (2015) Criterion Validation Testing of Clinical Metrology Instruments for Measuring Degenerative Joint Disease Associated Mobility Impairment in Cats. PLoS One 10:e0131839.

Gruen ME, Griffith E, Thomson A, Simpson W, Lascelles BD (2014) Detection of clinically relevant pain relief in cats with degenerative joint disease associated pain. J Vet Int Med 28:346-350.

Benito J, Hansen B, Depuy V, Davidson GS, Thomson A, Simpson W, Roe S, Hardie E, Lascelles BD (2013b) Feline musculoskeletal pain index: responsiveness and testing of criterion validity. J Vet Int Med 27:474-482.

Benito J, Depuy V, Hardie E, Zamprogno H, Thomson A, Simpson W, Roe S, Hansen B, Lascelles BD (2013a) Reliability and discriminatory testing of a client-based metrology instrument, feline musculoskeletal pain index (FMPI) for the evaluation of degenerative joint disease-associated pain in cats. Vet J 196:368-373.

Purpose:
To measure the pet owner’s assessment of the severity of disturbed sleep due to chronic pain

Description and Characteristics:
The SNoRE is a questionnaire with appropriate readability and proven discriminatory ability. Full validity testing is continuing, and further versions of the SNoRE may well take place in the future.

Funding for Development:
The development of this instrument was funded by the Translational Research in Pain (TRiP) Laboratory

References:
Knazovicky D, Tomas A, Motsinger-Reif A, Lascelles BDX. Initial evaluation of nighttime restlessness in a naturally occurring canine model of osteoarthritis pain. PeerJ. 2015 Feb 17;3:e772. doi: 10.7717/peerj.772. eCollection 2015. PMID: 25722957 (SNoRE version 1.0)

Gruen ME, Samson D, Lascelles BDX. Functional linear modeling of activity data shows analgesic-mediated improved sleep in dogs with spontaneous osteoarthritis pain”. Sci Rep. 2019 Oct 2;9(1):14192. doi: 10.1038/s41598-019-50623-0. PMID: 31578432 (SNoRE version 2.0)

Request the SNoRE Evaluation

Purpose:
To measure the pet owner’s assessment of difficult it is for their cat to perform certain specific activities. It has been used to evaluate the impact of osteoarthritis or degenerative joint disease associated pain in cats.

Description and Characteristics:
The Client Specific Outcome Measure was originally developed for use in dogs where it was adapted from the Cincinatti Orthopedic Disability Index (Gingerich & Strobel 2003) and then further adapted for use in cats (Lascelles et al. 2010). Its appeal is that the activities followed are individualized for each individual animal in their own environment, making it potentially more relevant than set questions on a questionnaire. It allows owners, working with a trained clinician, to select a set number of activities that their cat is impaired in performing, rate the amount of difficultly the cat has in performing those activities (currently recommended scale from 5=impossible to 1=no problem). The CSOM, once constructed, is used to follow this set of activities over time. Change from baseline in total score (the sum of scores across the 3 activities) is used as the outcome of interest to monitor the progression of impairment, or response to therapy.

Funding for Development:
The CPRL is very grateful to Morris Animal Foundation and to Novartis Animal Health for sponsoring the work that has led to the adaptation and assessment of the CSOM for cats. Further assessment of the CSOM has been possible through its use in studies funded by Boehringer Ingelheim Vetmedica, Nexvet Australia Pty Ltd and Elanco Animal Health.

References and studies using and evaluating the CSOM:

  • Gingerich DA, Strobel JD. Use of client-specific outcome measures to assess treatment effects in geriatric, arthritic dogs: Controlled clinical evaluation of a nutraceutical. Vet Ther. 2003;4(4):376-86
  • Lascelles BDX, Hansen BD, Roe S, Depuy V, Thomson A, Pierce CC, et al. Evaluation of client-specific outcome measures and activity monitoring to measure pain relief in cats with osteoarthritis. Journal of Veterinary Internal Medicine. 2007;21(3):410-6.
  • Gruen ME, Thomson AE, Griffith EH, Paradise H, Gearing DP, Lascelles BDX. A feline-specific anti-nerve growth factor antibody improves mobility in cats with degenerative joint disease-associated pain: A pilot proof of concept study. J Vet Intern Med. 2016 Jul;30(4):1138-48. doi: 10.1111/jvim.13972. Epub 2016 Jun 22. PMID: 27334504
  • Margaret E. Gruen, Emily H. Griffith, Andrea E. Thomson, Wendy Simpson, B. Duncan X. Lascelles. Criterion validation testing of Clinical Metrology Instruments for measuring degenerative joint disease associated mobility impairment in cats. PLoS One. 2015 Jul 10;10(7):e0131839. doi: 10.1371/journal.pone.0131839. eCollection 2015. PMID: 26162101
  • Reliability and discriminatory testing of a client-based metrology instrument, Feline Musculoskeletal Pain Index – FMPI, for the evaluation of degenerative joint disease associated pain in cats. Benito J, Hardie E, Zamprogno H, Thomson A, Simpson W, Roe S, Hansen B, Lascelles BDX     |   The Veterinary Journal, 2013 Jun;196(3):368-73

Instructions & Forms

NC State Translational Research in Pain (TRiP) Feline Musculoskeletal Pain, Muscle Atrophy and Sensitivity Scoring Systems

Feline Muscle Joint Assessment

Purpose:
To identify cats who may have DJD (arthritis) associated pain. This is not a diagnostic
tool, rather a tool to screen for the possibility of DJD-pain being present. The checklist
represents a starting point for discussion with owners and further veterinary
investigation as appropriate.

Description and Characteristics:
The MiPSC is a screening checklist that was developed using a data-driven approach to
develop a clinically useful checklist to identify cats who are likely to have DJD-
associated pain.

Funding for Development:
Data used for the development of this checklist was generated over 12 years of clinical
studies at NC State Translational Research in Pain. Salary support for Dr. Enomoto to
collate and analyze data was provided by Zoetis.

References:
Enomoto M, Lascelles BDX, Gruen ME. Development of a checklist for the detection of
degenerative joint disease-associated pain in cats. J Feline Med Surg. 2020
Dec;22(12):1137-1147. doi: 10.1177/1098612X20907424. Epub 2020 Mar 3. PMID:
32122226

Checklist