Predictive value of the Ewing score to differentiate Parkinson disease from multisystem atrophy. Results of a retrospective 15 year follow-up evaluation of 105 patients

Aim: to verify the predictivity of Ewing score (ES) for differentiation of patients (pts) with Multiple System Atrophy (MSA) from those with Parkinson Disease (PD). Method: 105 pts (55 PD, 50 MSA) studied with the 5-tests ES [0-1/10(normal), 2-4/10(borderline), 5-10/10(abnormal). MSA indicators during FU were: (a) rate of progression, (b) symmetry of parkinsonian signs, (c) occurrence of resting tremor during the first three years, (d) acute and chronic challenge with dopaminergic drugs, (e) mortality (f) high field MRI. Results: Onset symmetric in 20%, tremor absent at onset in 47%, response to dopaminergic drug challenges inadequate in 27%, rapid progression of disease in 34%, MRI abnormal in 12%. 22 of 29 with initial diagnosis of PD, had ES ≥ 4 and developed typical sign of MSA during the FU. ES ≥ 4 showed 70%sensitivity, 78%specificity, 74.4%PPV, 74.1%NPV and 74.3%diagnostic accuracy, in differentiating MSA from PD. Mortality was 87.5%(MSA) and 60%(PD). Conclusions: ES is adequate for early diagnosis of MSA and a reliable indicator of unfavorable outcome in parkinsonian patients. MSA-induced neurological derangement correlated with the progression of autonomic nervous system impairment.