Shortened olfactory identification testing to differentiate parkinsonian syndromes

Area of Science:

• Neurology
• Neuroscience
• Diagnostic Medicine

Background:

• Olfactory testing is crucial for differentiating Parkinson's disease (PD) from atypical parkinsonian disorders (APD).
• Abbreviated olfactory tests exist, but lack validation in independent cohorts.
• This study evaluates abbreviated Sniffin Sticks' identification tests (SS-I) for PD vs. APD discrimination.

Purpose of the Study:

• To assess the diagnostic accuracy of abbreviated Sniffin Sticks' identification tests (SS-I) in distinguishing Parkinson's disease (PD) from atypical parkinsonian disorders (APD).
• To identify abbreviated SS-I versions that are non-inferior to the full test in an independent cohort.

Main Methods:

• Collected SS-I results from 175 PD and 90 APD patients.
• Identified 8 abbreviated SS-I versions from literature.
• Compared diagnostic accuracy (AUC) of abbreviated tests against the full SS-I using DeLong test and Monte Carlo cross-validation.

Main Results:

• The full SS-I demonstrated good diagnostic accuracy (AUC: 0.81).
• Three abbreviated SS-I versions (7, 8, or 12 odors) were non-inferior to the full test (AUCs >0.80).
• Five abbreviated versions showed lower accuracy (AUCs <0.78) and suboptimal performance.

Conclusions:

• Three abbreviated SS-I tests, utilizing seven or more odors, retain significant diagnostic value for differentiating PD from APD.
• These validated abbreviated tests offer a potentially more efficient diagnostic tool.
• Results were consistent after cross-validation, confirming generalizability.