Construction and validation of the Dynamic Parkinson Gait Scale (DYPAGS)

Abstract

a b s t r a c tThe dynamic evaluation of Parkinson's disease (PD)-related episodic gait disturbances in routine is challenging. Therefore, the aim of our study was to assess the reliability/validity of the Dynamic Parkinson Gait Scale (DYPAGS) composed of eight relevant items for the objective quantification of PD gait features: walking forwards/backwards/with dual-task, turning to both sides, imaginary obstacle avoidance with both legs and passing through narrow spaces. The scale was validated on thirty-five patients with mild to severe parkinsonism in their habitual "on-state". A shorter 6 item-version was designed on the basis of a principal component analysis. No significant floor/ceiling effect was detected. The internal consistency was excellent. The levels of interrater agreement, precision and minimal detectable change were adequate. The criterion-related validity was demonstrated by strong correlations with the DYPAGS scores and those at the gait subscales of the Tinetti Mobility Test and MDS-UPDRS. The construct validity was assessed by moderate-strong correlations with the Freezing of Gait Questionnaire, mobility index of the PD Questionnaire (PDQ-39), disease duration and levodopa equivalent daily doses. Statistical analyses using the coefficient of determination showed that both DYPGAS versions were superior to the other instruments to identify patients with gait disturbances with poorer response to dopaminergic treatment. Full and short DYPAGS are reliable instruments for the quantification of "on" PD-related episodic gait disturbances. The full version is sensitive to detect subtle disturbances in mild parkinsonism. The shorter one is easily administered and reliably quantifies gait disturbances in moderate to severe parkinsonism. We recommend their use for research and clinical practice.

Reliability and Validity Study of the Chamorro Assisted Gait Scale for People with Sprained Ankles, Walking with Forearm Crutches

“…Regarding the statistical results obtained on reliability and validation of the Scale, we realized that the items were not redundant, although some of them had correlations exceeding 0.80[ 9 ]. However, no systematic patterns of high or low frequency were observed, so that the results did not suggest removing any item from the Scale.…”

“…- Published evidence : A comprehensive and critical literature review was carried out to identify the variables of interest and to guide the selection of item format and characteristics as well as the creation of the scoring model. The chosen scales were Tinetti Scale[ 5 ], Clinical Gait and Balance Scale[ 1 ], Dynamic Parkinson Gait Scale[ 9 ], Coding of eight criteria of qualitative gait analysis or “Codification des huit critères d´analyse qualitative de la marche” by Viel (Viel Coding)[ 28 ], Rivermead Visual Gait Assessment form[ 29 ] and Shaw Gait Assessment Tool[ 30 ]. The items extracted were: step symmetry, step length, step duration, step continuity and rhythmicity, trunk deviations, synchrony between arms and legs, attitude during gait, gait variability and walking while performing a cognitive dual-task.…”

“…Correlations under 0.30 indicate a low relation between the items. On the contrary, two items would be considered as redundant if their Spearman correlation coefficient exceeded 0.80[ 9 ].…”

“…Currently, the existing specific functional gait measures are aimed at patients with neurological, geriatric and cardiovascular diseases. Amongst these tools are: Tinetti Scale to assess gait and balance[ 5 ] which contains adaptations for neurological patients and elderly people; Gait and balance[ 1 ] and Parkinson Dynamic Gait Scale[ 9 ], amongst others, intended for Parkinson patients[ 10 ]; Wisconsin Gait Scale useful in hemiplegia[ 11 ]; Observational Gait Scale for children with cerebral palsy[ 3 ]; Ten-Meter Walk Test, used in strokes and other neurological disorders[ 12 ]; or Six-Minute Walk Test[ 13 ], designed for patients with cardiovascular diseases. However, there are many patients who do not have these pathologies, yet require assessment for abnormal gait over a long time due to a lower limb musculoskeletal injury[ 14 ].…”

Characterizing freezing of gait in Parkinson's disease: Models of an episodic phenomenon

“…Based on the above analysis and the awareness of how difficult it is to elicit FOG frequently and consistently in research laboratories, the freezer/non‐freezer comparison remains a useful paradigm for hypothesis generation. To optimize the paradigm and enhance data interpretation, we recommend the following: (1) define subgroups according to the Snijders et al algorithm, (2) use a validated and standardized clinical protocol to observe and rate FOG, (3) develop consensus criteria for defining non‐freezers, (4) report LED and cluster patients according to FOG l ‐dopa–responsiveness, (5) match patients for disease severity and global cognitive capacity, and (6) use sample sizes that allow for statistical correction for additional confounders. Nutt et al 54 questioned whether the dichotomy between freezers and non‐freezers was better replaced by a continuous spectrum ranging from absent to severe FOG.…”