The internal consistency and validity of the Self-Assessment Parkinson's Disease Disability Scale.
OBJECTIVE
To test the consistency and validity of the Self-assessment Parkinson's Disease Disability Scale in patients with Parkinson's disease living at home.


METHODS
Patients with Parkinson's disease responded to a set of questionnaires. In addition, an observation of the performance of daily activities was carried out on a subgroup.


METHODS
Patients with Parkinson's disease living at home (n = 142).


METHODS
The Self-assessment Parkinson's Disease Disability Scale (SPDDS), the Hoehn & Yahr Rating Scale (H&Y), and the Sickness Impact Profile (SIP68). The observation concerned nine activities that correspond to items of the 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 (Loevinger's H = 0.64): patients had least difficulty with 'washing' and 'brushing teeth' and most difficulty with 'turning in bed', 'travelling by public transport' and 'writing a letter'. Validity of the SPDDS was good: the relationship between the SPDDS questionnaire and the H&Y rating scale, the SIP68 and the results of the observation was strong and significant.


CONCLUSIONS
The SPDDS is a unidimensional instrument measuring disabilities in Parkinson's disease patients living at home.
Biemans
M A
MA
Practice for Physical Therapy and Manual Therapy de Traay Driebergen, The Netherlands.
Dekker
J
J
van der Woude
L H
LH
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006233:Persons with Disabilities / Q000145:classification*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000145:classification* / Q000503:physiopathology / Q000523:psychology; D012111:Residence Characteristics; D012647:Self-Assessment; D012720:Severity of Illness Index; D018434:Sickness Impact Profile; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires / Q000592:standards*