Reliability of the Modified Nine Hole Peg Test in Healthy Adults and Individuals with Hemiparetic Stroke

Objectives: This study examined whether the reliability of the Nine Hole Peg Test (NHPT) is improved by a modification (mNHPT) that confines the peg insertion/removal order to one way to reduce the degree of freedom of spatial strategies.Methods: Participants performed the NHPT and mNHPT three times each in two sessions with an interval of 3–5 days. Healthy adults used their non-dominant hand (n=40), while those with hemiparetic stroke used their affected (n=40) or unaffected hand (n=40). The mean value of three trials from each session was used for analyses. The reliabilities of the NHPT and mNHPT during the two sessions were assessed via intraclass correlation coefficients (ICCs) and Bland–Altman analysis.Results: The ICCs of the NHPT and mNHPT were 0.49 and 0.66, respectively, in healthy participants, and 0.91 and 0.94, respectively, in participants with stroke, regardless of the hand used. A significant fixed bias between the sessions was observed in both tests, except for participants with stroke who used their affected hand. Proportional biases were noted in the mNHPT results of healthy participants and in the NHPT and mNHPT results of participants with stroke who used their affected hand. The limits of agreement (lower, upper) in the affected hand were −11.0 and 9.5 for the NHPT and −8.0 and 6.2 for the mNHPT.Conclusions: Reduced degrees of freedom in the spatial strategy improved the relative reliability and reduced measurement errors in the NHPT. However, fixed and proportional biases were still evident.