Screening Tool Differentiates Progressive Supranuclear Palsy and Parkinson Disease

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Differentiating the early stages of progressive supranuclear palsy from Parkinson disease can be challenging.
Differentiating the early stages of progressive supranuclear palsy from Parkinson disease can be challenging.

The ECAS [Edinburgh Cognitive and Behavioral ALS Screen] — a 15- to 20-minute assessment that is used to detect cognitive and behavioral changes in motor disorders — may be a simple and effective tool for the differentiation of progressive supranuclear palsy (PSP) from Parkinson disease (PD), according to a study in Parkinson's Disease.

A total of 11 patients with PSP and 30 with PD admitted to a specialized neurology and neurosurgery hospital in the United Kingdom were recruited. Mean illness durations for PSP and PD were 3.73 years (range, 1 to 11 years) and 5.67 years (range, 0 to 14 years), respectively. The researchers also recruited 40 controls, none of whom had a psychiatric or neurologic history.

The researchers employed the ECAS, which assessed verbal fluency, executive function, language, memory, and visuospatial domains. The maximum score on the ECAS is 136, with lower scores demonstrating worse performance. Impairment was defined as a score of <2 SD on the ECAS.

Patients with PSP had lower scores on the ECAS compared with patients with PD and controls; patients with PD also demonstrated lower ECAS scores compared with controls (all P <.017). Worse performance on the verbal fluency, language, executive function, and memory domains was demonstrated in patients with PSP vs those with PD and controls (all P <.017). Patients with PD demonstrated worse scores on executive function compared with controls (P <.017).

In the post hoc analysis of individual domains, patients with PSP performed significantly worse on fluency than those with PD and controls (all P <.017), with a significant effect of diagnosis occurring on fixed fluency (F [2, 21.63] = 8.30; P <.017) and free fluency (F [2, 23.16] = 15.19; P <.017).

Similar group effects were seen on spelling (F [2, 76] = 10.58; P <.017), immediate recall (F [2, 24.04] = 11.47; P <.017),  retention (F [2, 20.69] = 8.92; P <.017), reverse digit span (F [2, 25.96] = 7.60; P <.017), alternation (F [2, 22.92] = 5.66; P <.017), and social cognition (F [2, 20.42] = 9.49; P <.017). Fluency was the best PSP predictor, representing a specificity and sensitivity of 80% and 82%, respectively (AUC 0.84; SE = 0.08; P <.01).

The ECAS was found to be highly specific (86.8%) and sensitive (91.0%) for differentiating patients with PSP from controls (AUC 0.91; SE = 0.67; P <.001). In addition, the ECAS was found to demonstrate specificity (76.7%) and sensitivity (72.7%) for distinguishing between PSP and PD (AUC 0.80; SE = 0.09; P <.01).

The researchers suggest “that the ECAS is suited for bedside use for detecting cognitive impairment in Parkinsonian syndromes and for distinguishing different cognitive profiles within these, in order to support differential diagnosis.”

Reference

Foley JA, Niven EH, Paget A, et al. Sensitivity and specificity of the ECAS in Parkinson's disease and progressive supranuclear palsy. Parkinsons Dis. 2018;2018:2426012.

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