Staging of cognitive impairment in Parkinson's disease: validity of Quick Dementia Rating System.

PURPOSE: This study aimed to investigate the ability of the Quick Dementia Rating System (QDRS) to discriminate patients with PD who have mild cognitive impairment from those without cognitive impairment and those with dementia. METHOD: A total of 105 patients with PD were classified as without cognitive impairment (N = 32), with mild cognitive impairment (N = 23), and PDD (N = 50), according to their score on clinical dementia rating. Multivariate regression analysis was performed considering age, education, and disease severity as covariates and mild cognitive impairment or dementia as outcome variables. Receiver operating characteristic curve analysis was carried out to derive the optimal cut-off points. RESULTS: The cut-off point >2.5 (sensitivity = 86.96%, area under curve (AUC) = 0.88) was obtained for discriminating patients with mild cognitive impairment from those without cognitive impairment based on the total score of QDRS. The cut-off point >5 (sensitivity = 84%, AUC = 0.84) was derived for discriminating mild cognitive impairment from dementia based on the total score of QDRS. CONCLUSIONS: The results of this study showed a good discriminative validity of the QDRS for discriminating mild cognitive impairment from no cognitive impairment and dementia in patients with PD.IMPLICATIONS FOR REHABILITATIONThe Quick Dementia Rating System has a good discriminative validity for diagnosing mild cognitive impairment from normal cognitive function in Parkinson's disease.The Quick Dementia Rating System has a good discriminative validity for diagnosing mild cognitive impairment from dementia in Parkinson's disease.The Quick Dementia Rating System could be suggested as a routine rapid cognitive screening tool for patients with Parkinson's disease.

Time-course investigation of postural sway variability: Does anxiety exacerbate the sensory reweighting impairment in chronic stroke survivors?

Although anxiety is one of the most prevalent psychological disorders in stroke survivors, its effect on sensory reweighting has not yet been fully studied. The aim of this work was to investigate how anticipation of collision avoidance events affects sensory reweighting in chronic stroke survivors with low and high levels of anxiety (LA-stroke and HA-stroke, respectively), as compared with healthy controls (HC), under the condition of perturbed proprioception. Eighteen LA-stroke and 18 HA-stroke survivors, as well as 18 gender- and age-matched HC, participated in this study. Postural sway variability (i.e. Root Mean Square (RMS) of the COP velocity) was measured for a duration of 180 s under two conditions: quiet standing and standing while predicting random virtual spheres to be avoided. Proprioceptive perturbation was simulated using bilateral Achilles tendon vibration at mid duration (60 s) for both conditions. The results showed that the HC were able to timely use visual anticipation to reduce the postural sway variability induced by tendon vibration. However, marked delay in using such anticipation was observed in stroke participants, especially in the HA-stroke group, as indicated by a significant decrease in the RMS of the COP velocity late in the vibration phase. This is the first study to consider the effect of anxiety while comparing sensory reweighting between stroke and healthy participants. The results indicated that chronic stroke survivors, particularly those with HA, could not efficiently use sensory reweighting to maintain balance in sensory conflicting conditions, which may subject them to loosing balance and/or falling. These findings are critical for future assessment and planning of rehabilitation interventions and balance in chronic stroke survivors.

Reliability and Validity of Fall Efficacy Scale-International in People with Parkinson's Disease during On- and Off-Drug Phases.

PURPOSE: Since fear of falling may be one of the main problems in people with Parkinson's disease (PD), its assessment with valid tools is necessary in both drug phases. This study was carried out to investigate the psychometric attributes of the Fall Efficacy Scale-International (FES-I) in people with PD, both in On and Off phases. METHODS: One hundred twenty-four patients with PD (mean age ± standard deviation, 60.33 ± 12.59 years) were assessed with the FES-I, both in On- and Off-drug phases. Dimensionality, internal consistency, and test-retest reliability were, respectively, explored by means of factor analysis, Cronbach's alpha, and Intraclass Correlation Coefficient. Convergent validity of FES-I was established with Visual Analog Scale-Fear of Falling, Berg Balance Scale, and Functional Reach Test. Parkinson's Disease Questionnaire-39 and Unified Parkinson Disease Rating Scale-Activities of Daily Living were also applied. Discriminative validity was tested between patients with and without a history of falling. RESULTS: Factor analysis showed two factors for On- and one factor for Off-drug phase. Internal consistency (α = 0.96, On phase; 0.98, Off phase) and test-retest reliability (0.94; 0.91) were satisfactory in both drug phases. There was a moderate/high correlation (r S = |0.50-0.70|) between FES-I and Visual Analog Scale-Fear of Falling, Berg Balance Scale, and Functional Reach Test. Parkinson's Disease Questionnaire-39 and Unified Parkinson Disease Rating Scale-Activities of Daily Living were achieved in both drug phases too. The sensitivity of FES-I to discriminate Parkinson's disease with and without falls showed moderate effect size in both phases. CONCLUSION: This study verified that FES-I is unidimensional, reliable, and valid to measure the Fear of Falling during On- and Off-drug phases in people with PD.