Dr Libby Proud1, Dr Belinda Bilney2, Dr Kimberly Miller3, Professor Meg Morris4, Associate Professor Jennifer McGinley1
1The University Of Melbourne, Parkville, Australia, 2Australian Catholic University, Ballarat, Australia, 3Sunny Hill Health Centre for Children, Vancouver, Canada, 4Healthscope and La Trobe University, Bundoora, Australia
To investigate the test-retest reliability and construct validity of 9-Hole Peg Test (9HPT) and Purdue Pegboard Test (PPT) scores in people with Parkinson’s disease (PD).
Thirty participants with mild to moderately severe PD and mean disease duration of 6.4 years (SD 4.5) completed the pegboard tests on two days with a one-week interval, to evaluate test-retest reliability. On each day they were tested 1) when PD medication is likely to be most effective (‘on’) and 2) towards the ‘end of dose’ when motor performance typically declines.
To investigate construct validity, baseline pegboard scores were compared with age-equivalent normative values (known groups validity) and were correlated with self-reported hand function (convergent validity), rated by the Manual Ability Measure-36.
In the PD medication ‘on’ phase and at ‘end-of-dose’, test-retest reliability was moderate-to-good for 9HPT scores (ICC = 0.7-0.8) and good for PPT subtests (ICC ≥ 0.90). Participants’ pegboard scores were mostly poorer than normative age-matched values (p < 0.05). Pegboard scores were moderately correlated with self-reported hand function (r = 0.31-0.5), but associations with PPT subtests were generally higher.
Significance of the findings to allied health: Dexterity-related hand problems are very common, occurring in around 90% of people with PD, and it is important to use valid and reliable outcome measures for clinical evaluation. While both pegboards showed adequate reliability and validity, the PPT may be a more sensitive measure in people with PD. This study informs the clinical measurement of dexterity in people with PD.
Libby Proud is a physiotherapist, with a special interest in the management of people living with neurological disorders. Libby’s focus in recent years has been the assessment and treatment of people with Parkinson’s disease. In her PhD, Libby investigated upper limb measurement in Parkinson’s disease and the clinimetric properties of selected dexterity outcome measures, and has published peer-reviewed journal articles on this topic. She now works at The University of Melbourne as a researcher and tutor.