Validation of the NOSCA - nurses' observation scale of cognitive abilities

Abstract

Aims and objectives. To examine the psychometric properties of the Nurses' Observation Scale for Cognitive Abilities. Background. Nurses' Observation Scale for Cognitive Abilities is a behavioural rating scale comprising eight subscales that represent different cognitive domains. It is based on observations during contact between nurse and patient. Design. Observational study. Methods. A total of 50 patients from two geriatric wards in acute care hospitals participated in this study. Reliability was examined via internal consistency and inter-rater reliability. Construct validity of the Nurses' Observation Scale for Cognitive Abilities and its subscales were explored by means of convergent and divergent validity and post hoc analyses for group differences. Results. Cronbach's alphas of the total Nurses' Observation Scale for Cognitive Abilities and its subscales were 0.98 and 0.66-0.93, respectively. The item-total correlations were satisfactory (overall > 0.4). The intra-class coefficients were good (37 of 39 items > 0.4). The convergent validity of the Nurses' Observation Scale for Cognitive Abilities against cognitive ratings (MMSE, NOSGER) and severity of dementia (Clinical Dementia Rating) demonstrated satisfactory correlations (0.59-0.70, p < 0.01), except for IQCODE (0.30, p > 0.05). The divergent validity of the Nurses' Observation Scale for Cognitive Abilities against depressive symptoms was low (0.12, p > 0.05). The construct validity of the Nurses' Observation Scale for Cognitive Abilities subscales against 13 specific neuropsychological tests showed correlations varying from poor to fair (0.18-0.74; 10 of 13 correlations p < 0.05). Conclusions. Validity and reliability of the total Nurses' Observation Scale for Cognitive Abilities are excellent. The correlations between the Nurses' Observation Scale for Cognitive Abilities subscales and standard neuropsychological tests were moderate. More conclusive results may be found if the Nurses' Observation Scale for Cognitive Abilities subscales were to be validated using more ecologically valid tests and in a patient population with less cognitive impairment. Relevance to clinical practice. Use of the Nurses' Observation Scale for Cognitive Abilities yields standardised, reliable and valid information about patient's cognitive behaviour in daily practice. The Nurses' Observation Scale for Cognitive Abilities aids in tailoring nursing interventions to patients' specific cognitive needs. We advocate the implementation of the Nurses' Observation Scale for Cognitive Abilities both in research and at geriatric units in acute care hospitals.