Validation of a new scale to assess olfactory dysfunction in patients with Parkinson's disease

MILLAR VERNETTI, PATRICIO; PEREZ LLORET, SANTIAGO; ROSSI, MALCO; CERQUETTI, DANIEL; MERELLO, MARCELO

PARKINSONISM & RELATED DISORDERS

ELSEVIER SCI LTD

Año: 2012 vol. 18 p. 358 - 361

1353-8020

Bakckground: Olfactory dysfunction is present in up to 90% of Parkinson´s disease (PD) patients. It is usually evaluated by means of objective standardized tests; however no self-administered scales have been developed for olfactory dysfunction bedside assessment. We present validation of a new scale to assess this symptom in PD patients. Methods: Seventy-five PD patients and 25 control subjects were evaluated using a Hyposmia Rating Scale developed in-house, combined with the extended Sniffin´ Sticks test. Results: Total score of the 6-item Hyposmia Rating Scale showed significant correlation with threshold, discrimination, identification and total Sniffin´ Sticks test scores (r = 0.53; r = 0.60; r = 0.57; r = 0.65 respectively, p < 0.001 for all values). Area under the curve of the receiver operating curve for the ability of Hyposmia Rating Scale to discriminate patients with Sniffin´ Sticks test total scores below or above the cut-off point was 80 ± 6% (p < 0.001). Considering Sniffin´ Sticks test as the gold standard method for olfactory dysfunction detection, an affirmative response to a single screening question about smelling ability problems showed 35% sensitivity (95%CI = 23-47%) and 100% specificity. The best cut-off point for Hyposmia Rating Scale was 22.5 with a sensitivity of 70% (60-81%) and a specificity of 85% (65-100%). Conclusion: The Hyposmia Rating Scale here presented may offer a simple, cost-effective, time-saving and reliable approach to evaluate olfactory dysfunction in PD patients. © 2011.