Identifying Key Components for Diagnosing Stiff Person Syndrome Spectrum Disorders: A Sensitivity and Specificity Study (P4-5.018)

Abstract

<h3>Objective:</h3> To evaluate the sensitivity and specificity of clinical and paraclinical features of stiff person syndrome spectrum disorders (SPSD) to help aid in their diagnosis. <h3>Background:</h3> SPSD are a group of rare, disabling neuroimmunological disorders. SPSD is often challenging to diagnose since it can be insidious in nature and hallmark symptoms and signs are not readily identified by clinicians. Moreover, there is limited data on which clinical feature(s) and diagnostic test(s) are most helpful in making a diagnosis of SPSD. <h3>Design/Methods:</h3> The Johns Hopkins SPS center’s longitudinal observational database was used, which contains clinical characteristics, and diagnostic studies of people with SPSD. Patients with a diagnosis of either Classic SPS or SPS-plus phenotypes were compared to patients who were evaluated for SPSD but received an alternative diagnosis (control group). Each clinical and paraclinical feature important for a diagnosis of SPSD was evaluated for its sensitivity and specificity, and used to define its diagnostic odds ratio. <h3>Results:</h3> A total of 161 Classic SPS cases, 45 SPS-plus cases, and 66 controls were included. The most sensitive findings for classic SPS included clinical involvement of the lower extremities (98.1%), stress as a trigger for physical symptoms (96.8%), paravertebral stiffness/tightness (95.7%), and abnormal gait (91.4%). The most specific findings for SPS included characteristic EMG findings (98.3%), a high GAD65 antibody titer defined as &gt;1000IU/mL and/or &gt;20nmol/L (98.2%), and the presence of hyperlordosis on examination (87.1%). For SPS-plus, cerebellar and brainstem involvement were also highly specific (98.5% and 100%, respectively) as were the aforementioned paraclinical tests. Analyses are ongoing to assess whether major and minor criterion can be developed for a more accurate diagnosis leveraging the above data. <h3>Conclusions:</h3> This study identified key clinical and paraclinical tests that can help enhance diagnostic accuracy of SPSD. Further studies can help validate these findings and inform development of revised diagnostic criteria. <b>Disclosure:</b> Dr. Roy has nothing to disclose. Miss Hu has nothing to disclose. The institution of Dr. Wang has received research support from Genentech. The institution of Dr. Fitzgerald has received research support from NIH. The institution of Dr. Fitzgerald has received research support from National MS Society. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Autobahn. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Newsome has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for EMD Serono. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Greenwich Biosciences. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Bristol Myers Squibb. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Horizon Therapeutics. The institution of Dr. Newsome has received research support from Biogen. The institution of Dr. Newsome has received research support from Genentech/Roche. The institution of Dr. Newsome has received research support from Department of Defense. The institution of Dr. Newsome has received research support from Patient Centered Outcomes Research Institute. The institution of Dr. Newsome has received research support from National MS Society. The institution of Dr. Newsome has received research support from The Stiff Person Syndrome Research Foundation. Dr. Newsome has received personal compensation in the range of $5,000-$9,999 for serving as a Clinical adjudication committee member for clinical trial with medDay Pharmaceuticals. Dr. Newsome has received personal compensation in the range of $10,000-$49,999 for serving as a Lead PI for Clinical Trial with Roche.