Maje. Biemans et al., The internal consistency and validity of the Self-Assessment Parkinson's Disease Disability Scale, CLIN REHAB, 15(2), 2001, pp. 221-228
Objective: To test the consistency and validity of the Self-assessment Park
inson's Disease Disability Scale in patients with Parkinson's disease livin
g at home.
Design: Patients with Parkinson's disease responded to a set of questionnai
res. In addition, an observation of the performance of daily activities was
carried out on a subgroup.
Setting and subjects: Patients with Parkinson's disease living at home (n =
142).
Measures: The Self-assessment Parkinson's Disease Disability Scale (SPDDS),
the Hoehn & Yahr Rating Scale (H&Y), and the Sickness Impact Profile (SIP6
8). The observation concerned nine activities that correspond to items of t
he SPDDS questionnaire.
Results: Internal consistency of the SPDDS was very high (Cronbach's alpha
= 0.97; reliability rho = 0.97). The items of the SPDDS are hierarchical (L
oevinger's H= 0.64): patients had least difficulty with 'washing' and 'brus
hing teeth' and most difficulty with 'turning in bed','travelling by public
transport' and 'writing a letter'. Validity of the SPDDS was good: the rel
ationship between the SPDDS questionnaire and the H&Y rating scale, the SIP
68 and the results of the observation was strong and significant.
Conclusion: The SPDDS is a unidimensional instrument measuring disabilities
in Parkinson's disease patients living at home.