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Uncovering indicators of the international classification of functioning, disability, and health from the 39-item Parkinson's disease questionnaire.

Nilsson MH, Westergren A, Carlsson G, Hagell P - Parkinsons Dis (2010)

Bottom Line: An iterative process using Rasch analysis produced five new items sets, two each for the BF and AP components and one representing E.Four of these were found to represent clinically meaningful variables: Emotional Impairment (BF), Gross Motor Disability (AP), Fine Motor Disability (AP), and Socioattitudinal Environment (E) with acceptable reliability (0.73-0.96) and fit to the Rasch model (total item-trait chi-square, 8.28-33.2; P > .05).These new ICF-based scales offer a means to reanalyze PDQ-39 data from an ICF perspective and to study its health components using a widely available health status questionnaire for people with PD.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Sciences, Lund University, P.O. Box 157, 221 00 Lund, Sweden.

ABSTRACT
The 39-item Parkinson's disease questionnaire (PDQ-39) is the most widely used patient-reported rating scale in Parkinson's disease (PD). However, recent studies have questioned its validity and it is unclear what scores represent. This study explored the possibility of regrouping PDQ-39 items into scales representing the International Classification of Functioning, Disability, and Health (ICF) components of Body Functions and Structures (BF), Activities and Participation (AP), and Environmental (E) factors. An iterative process using Rasch analysis produced five new items sets, two each for the BF and AP components and one representing E. Four of these were found to represent clinically meaningful variables: Emotional Impairment (BF), Gross Motor Disability (AP), Fine Motor Disability (AP), and Socioattitudinal Environment (E) with acceptable reliability (0.73-0.96) and fit to the Rasch model (total item-trait chi-square, 8.28-33.2; P > .05). These new ICF-based scales offer a means to reanalyze PDQ-39 data from an ICF perspective and to study its health components using a widely available health status questionnaire for people with PD.

No MeSH data available.


Related in: MedlinePlus

Distributions of the locations of people (upper histogram in each panel) and response category thresholds (lower histogram in each panel) on the common logit metric (positive values = more problems).  Response category thresholds are the locations where there is a 50/50 probability of endorsing either of two adjacent categories and represent the quantitative “notches” on the latent ruler defined by a set of items. (a) Item set BFa (items 17, 18, 20–22); (b) Item set BFb (items 30, 32, 33, 37–39); (c) Item set APa (items 1, 2, 4–7, 11, 12); (d) Item set APb (items 13–16, 24); (e) Item set E (items 23, 25, 26, 28, 29, 36).  Mean (SD) person locations are  BFa (panel (a)), −1.115 (1.951); BFb (panel (b)), −1.363 (1.096); APa (panel (c)), −0.814 (2.326); APb (panel (d)), −0.671 (1.370); E (panel (e)), −1.967 (1.355).
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fig2: Distributions of the locations of people (upper histogram in each panel) and response category thresholds (lower histogram in each panel) on the common logit metric (positive values = more problems). Response category thresholds are the locations where there is a 50/50 probability of endorsing either of two adjacent categories and represent the quantitative “notches” on the latent ruler defined by a set of items. (a) Item set BFa (items 17, 18, 20–22); (b) Item set BFb (items 30, 32, 33, 37–39); (c) Item set APa (items 1, 2, 4–7, 11, 12); (d) Item set APb (items 13–16, 24); (e) Item set E (items 23, 25, 26, 28, 29, 36). Mean (SD) person locations are BFa (panel (a)), −1.115 (1.951); BFb (panel (b)), −1.363 (1.096); APa (panel (c)), −0.814 (2.326); APb (panel (d)), −0.671 (1.370); E (panel (e)), −1.967 (1.355).

Mentions: Subsequent stepwise item reduction guided by fit and DIF statistics rendered the new item sets comprising five (BFa) to eight (APa) items each (Table 4). Total item-trait interaction (P > .056) and item level fit statistics (Table 4) suggested reasonable fit in all five instances, and reliabilities ranged between 0.73 (BFa) and 0.96 (APa). Figure 2 illustrates the locations of item response category thresholds relative to the locations of the sample for each item set. Inspection of these graphs shows a general tendency for the items (bars below the x-axes) to represent worse health than that experienced by the persons (bars above the x-axes). Furthermore, while the thresholds are able to map out a continuum for each scale, there are also several gaps as well as clusters along those continua (Figure 2).


Uncovering indicators of the international classification of functioning, disability, and health from the 39-item Parkinson's disease questionnaire.

Nilsson MH, Westergren A, Carlsson G, Hagell P - Parkinsons Dis (2010)

Distributions of the locations of people (upper histogram in each panel) and response category thresholds (lower histogram in each panel) on the common logit metric (positive values = more problems).  Response category thresholds are the locations where there is a 50/50 probability of endorsing either of two adjacent categories and represent the quantitative “notches” on the latent ruler defined by a set of items. (a) Item set BFa (items 17, 18, 20–22); (b) Item set BFb (items 30, 32, 33, 37–39); (c) Item set APa (items 1, 2, 4–7, 11, 12); (d) Item set APb (items 13–16, 24); (e) Item set E (items 23, 25, 26, 28, 29, 36).  Mean (SD) person locations are  BFa (panel (a)), −1.115 (1.951); BFb (panel (b)), −1.363 (1.096); APa (panel (c)), −0.814 (2.326); APb (panel (d)), −0.671 (1.370); E (panel (e)), −1.967 (1.355).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2957468&req=5

fig2: Distributions of the locations of people (upper histogram in each panel) and response category thresholds (lower histogram in each panel) on the common logit metric (positive values = more problems). Response category thresholds are the locations where there is a 50/50 probability of endorsing either of two adjacent categories and represent the quantitative “notches” on the latent ruler defined by a set of items. (a) Item set BFa (items 17, 18, 20–22); (b) Item set BFb (items 30, 32, 33, 37–39); (c) Item set APa (items 1, 2, 4–7, 11, 12); (d) Item set APb (items 13–16, 24); (e) Item set E (items 23, 25, 26, 28, 29, 36). Mean (SD) person locations are BFa (panel (a)), −1.115 (1.951); BFb (panel (b)), −1.363 (1.096); APa (panel (c)), −0.814 (2.326); APb (panel (d)), −0.671 (1.370); E (panel (e)), −1.967 (1.355).
Mentions: Subsequent stepwise item reduction guided by fit and DIF statistics rendered the new item sets comprising five (BFa) to eight (APa) items each (Table 4). Total item-trait interaction (P > .056) and item level fit statistics (Table 4) suggested reasonable fit in all five instances, and reliabilities ranged between 0.73 (BFa) and 0.96 (APa). Figure 2 illustrates the locations of item response category thresholds relative to the locations of the sample for each item set. Inspection of these graphs shows a general tendency for the items (bars below the x-axes) to represent worse health than that experienced by the persons (bars above the x-axes). Furthermore, while the thresholds are able to map out a continuum for each scale, there are also several gaps as well as clusters along those continua (Figure 2).

Bottom Line: An iterative process using Rasch analysis produced five new items sets, two each for the BF and AP components and one representing E.Four of these were found to represent clinically meaningful variables: Emotional Impairment (BF), Gross Motor Disability (AP), Fine Motor Disability (AP), and Socioattitudinal Environment (E) with acceptable reliability (0.73-0.96) and fit to the Rasch model (total item-trait chi-square, 8.28-33.2; P > .05).These new ICF-based scales offer a means to reanalyze PDQ-39 data from an ICF perspective and to study its health components using a widely available health status questionnaire for people with PD.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Sciences, Lund University, P.O. Box 157, 221 00 Lund, Sweden.

ABSTRACT
The 39-item Parkinson's disease questionnaire (PDQ-39) is the most widely used patient-reported rating scale in Parkinson's disease (PD). However, recent studies have questioned its validity and it is unclear what scores represent. This study explored the possibility of regrouping PDQ-39 items into scales representing the International Classification of Functioning, Disability, and Health (ICF) components of Body Functions and Structures (BF), Activities and Participation (AP), and Environmental (E) factors. An iterative process using Rasch analysis produced five new items sets, two each for the BF and AP components and one representing E. Four of these were found to represent clinically meaningful variables: Emotional Impairment (BF), Gross Motor Disability (AP), Fine Motor Disability (AP), and Socioattitudinal Environment (E) with acceptable reliability (0.73-0.96) and fit to the Rasch model (total item-trait chi-square, 8.28-33.2; P > .05). These new ICF-based scales offer a means to reanalyze PDQ-39 data from an ICF perspective and to study its health components using a widely available health status questionnaire for people with PD.

No MeSH data available.


Related in: MedlinePlus