Title:
A rating scale for gait evaluation in cognitive deterioration (RSGE-CD): validation study.

Abstract:
A relationship between decline in mobility and walking performance and cognitive impairment exists in the elderly. Therefore, clinical assessment of gait and mobility may be relevant for diagnostic and therapeutic purposes. However, the rating scales used for evaluation of gait disorder in the context of cognitive deterioration were not designed or validated for that setting. The present study was aimed at checking the clinimetric properties of the Rating Scale for Gait Evaluation in Cognitive Deterioration (RSGE-CD), specifically developed for assessment of gait dysfunction across all stages of cognitive decline. Two hundred fifty six subjects were included in the study and classified according to the Global Deterioration Scale (control, subjective/mild cognitive impairment, or dementia). Patients with dementia had a diagnosis of probable Alzheimer's disease (73%) or dementia of combined etiology (27%). Cognitive and functional evaluations, the Tinetti scale, and timed tests were simultaneously applied with the tested scale, which is composed of two subscales: Functional ability and Examination. Exploratory factor analysis showed one factor (70% of the variance). Floor effect and skewness were observed in the control group, whereas internal consistency (Cronbach's alpha = 0.88-0.95), inter-observer and test-retest reliability (intraclass correlation coefficients ≥ 0.97) were satisfactory. Convergent validity with the other measures was ≥ 0.60 and the discriminant validity according to classification of subjects by cognitive state and other aspects was also satisfactory (p = 0.0001). The RSGE-CD showed low standard errors of measurement. In this first validation study, the RSGE-CD showed satisfactory clinimetric attributes for assessing gait and mobility across the complete range of cognitive state.