Retrospective audit of 26 atypical parkinsonian patients found orthoptic oculomotor and eye-tracker assessment agreed with final neurology diagnoses in ~80.8% of cases for distinguishing suspected PSP from non-PSP.

This work aids clinical phenotyping and early patient selection for trials or observational studies but provides little mechanistic or therapeutic insight, so its direct value for Parkinson's drug discovery is limited.

AIM: Progressive supranuclear palsy (PSP) is an atypical Parkinsonian disorder which, like other atypical Parkinsonian disorders, displays neurological motor and oculomotor signs at different stages along the disease course. The overlap in presenting signs between the disorders presents a diagnostic challenge for the clinician, particularly early on. Here we audit the role of orthoptic oculomotor and eye-tracker assessment for atypical Parkinsonian patients. METHOD: A retrospective analysis was conducted for 26 patients with atypical Parkinsonian signs, referred to orthoptics for oculomotor assessment. Orthoptic diagnoses were made after reviewing oculomotor range, doll's head manoeuvre, saccadic velocity, vergence, eyelid signs and fixation results. The orthoptic diagnoses were compared with the final neurology/neurosurgery diagnosis for consistency. RESULTS: Of the 19/26 cases who were diagnosed with 'suspected PSP' after orthoptic assessment, 14/19 (73.68%) had a final diagnosis of 'suspected PSP' by neurology/neurosurgery. In 5/19 cases (26.32%) the patients demonstrated PSP-like signs in orthoptics but later received alternative diagnoses. The orthoptic diagnosis was consistent with the final neurology/neurosurgery diagnosis for 'suspected non-PSP' in all seven cases. CONCLUSION: Suspected diagnoses after orthoptic assessment were consistent with the final neurology/neurosurgery department diagnoses in 80.77% of patients. We conclude that early orthoptic oculomotor and eye tracker assessment of atypical Parkinsonian patients is clinically effective for ruling PSP in or out of the clinical picture.