Table 2

Items that did not meet inclusion in the final instrument version of the PRUNE
Item Rationale for exclusion/modification
Deleted items
Pain during activity Contamination of pain and function concepts within item
Combing hair Not appropriate to all respondents; higher level of missingness
Using arms rise from a chair Highly correlated to tying shoes; less responsive
Pulling a heavy object Correlated to lifting a heavy object; lifting a 10 kg weight
Lifting a 10 kg weight As above; not all respondents understand 10 kg
Putting on a coat Respondent feedback suggested less relevant; poor item performance overall
Doing up buttons Cognitive interviews and task analysis suggests this item does not reflect sensory impairment of the ulnar nerve— the concept of fine motor control was covered by finger use question
Modified items
At night (while sleeping) Shift workers were not sure if at night meant during sleep or their night activity which was work. Added ( while sleeping to clarify)
Hold an object Item performance variable; however strong bio mechanical support and patient endorsement that some type of holding object with arm bent was difficult. Qualitative interviews indicated that respondents used a variety of reading devices and positions; and were not always clear that it meant a continuous activity. Item modified to specify one hour interval and allow multiple options for the object that was held clarifying that the elbow is bent
Eating Added specification of different eating utensils for cultural transferability
Control of the small finger Different respondents use either small, little or fifth finger to indicate the fifth digit. Motor dysfunction related to the ulnar comprise could include either deformity, lack of motor control— lay terms were used for these phenomena.
Finger use Finger use was a common difficulty reported by patients. It was most remarkably noted for keyboarding or musical instrument use but not all respondents perform these tasks therefore the question was modified to: Repeated finger movement (like when typing, playing instruments or moving small objects )

After item generation and initial iterative changes to the PRUNE, a larger potential instrument was tested on respondents. This larger subset of items underwent both cognitive interviewing and statistical analyses to determine the final subset of items included in the PRUNE.

MacDermid and Grewal

MacDermid and Grewal BMC Musculoskeletal Disorders 2013 14:146   doi:10.1186/1471-2474-14-146

Open Data