Introduction: GRASSP Version 1.0 is a clinical impairment measure designed specifically to assess the upper limb after traumatic cervical spinal cord injury (SCI). The GRASSP consists of 5 subtest scores that characterize the upper limb; it captures subtle changes in neurological impairment during the acute, sub‐acute, and chronic phases of recovery. Psychometric properties of reliability validity, responsiveness and minimally detectable difference are established.
The remaining psychometric property to be established is Minimally Clinical Important Difference (MCID), which is required to establish use in efficacy and interventional studies. The objectives of this study were to: 1) Establish the MCID values for the GRASSP and 2) To summarize how the GRASSP can be applied in clinical / interventional trials as a tool to define effectiveness of new therapies.
Methods: A prospective longitudinal study including 53 individuals with acute traumatic cervical SCI was conducted as a multi‐centre study. Serial testing consisted of GRASSP, International Standards for Neurological Classification for Spinal Cord Injury (ISNCSCI) and a patient questionnaire designed to acquire the patients perception of change over time were administered 0 to 10 days, 1, 3, 6, and 12 months post injury. Analysis: Using a validated anchor‐based approach patients rated their status as same, better and much better related to the specific domains of the GRASSP, the mean change in GRASSP scores was calculated for these groups.
Results: 53 individuals sustaining a traumatic cervical SCI with NLI ranging from C2 to T1 (AIS A = 11, B = 5, C = 16, D = 23) at baseline. MCID and minimally important different (MID) values for the group of individuals perceiving their upper limb impairment to be much better are presented in Table 1. Three calculations were done, anchor‐based, standard deviation and standard error of measure.
Conclusion: MCID of the GRASSP has been established and can be a useful measure to establish efficacy of interventions as well as meaningfulness of the change as it relates to the patient. Although, MCID remains to be an elusive psychometric property, the benefit of an available value / s contributes to the investigators understanding of the treatment effect. We recommend application of these MCID values for group‐level analysis when conducting research and interpreting data examining groups of patients as opposed to assessing individual patients. These MCID values may provide a basis for sample size calculations for future investigation using the GRASSP.