Primary progressive apraxia of speech: Clinico-pathological associations of left-right hemispheric dominance (S8.008)

Abstract

<h3>Objective:</h3> To determine whether there are differences in in demographics, clinicopathologic-neuroimaging or survival, between left-dominant, right-dominant, and symmetric PPAOS. <h3>Background:</h3> Primary progressive apraxia of speech (PPAOS) is a neurodegenerative syndrome associated with neuroimaging abnormalities affecting the lateral premotor cortex (LPC) and supplementary motor area (SMA). It is unclear whether relative greater damage to premotor regions in left/right hemisphere is associated with differences in baseline and/or longitudinal features. <h3>Design/Methods:</h3> Fifty-one prospectively recruited PPAOS patients who completed [¹⁸F]-fluorodeoxyglucose PET scanning were classified as left-dominant, right-dominant, or symmetric, based on visual assessment of the LPC and SMA on FDG-PET by independent raters. Statistical analyses were utilized to compared baseline and longitudinal features. Kaplan-Meyer curves and Cox proportional hazards were used to evaluate survival differences across groups. <h3>Results:</h3> 49% of PPAOS patients were identified as left-dominant, 31% as right-dominant, and 20% as symmetric. At baseline, there were no differences between groups. On longitudinal rates of clinical change, left-dominant PPAOS displayed a slower progression of Parkinsonian symptoms on the Unified Parkinson Disease Rating Scale-III (p=0.047), with a trend for slowest rates of progression in ideomotor apraxia (p=0.06) and motor speech severity (p=0.09) relative to other groups. Right-dominant PPAOS demonstrated the most rapid rates of progression of behavioral disturbances on the Frontal Behavioral Inventory (p=0.02), including disinhibition symptoms (p=0.02) and negative behaviors (p=0.05). The symmetric group had fastest worsening of dysarthria. There were no differences in survival, although a five-year increase in age at onset, but not group classification, was associated with shorter survival (Hazard Ratio = 1.32; p=0.007). Braak neurofibrillary tangle stage differed across groups (p=0.01). While not statistically significant, right-dominant PPAOS tended to have corticobasal degeneration (CBD) and left-dominant PPAOS had progressive supranuclear palsy (PSP) pathology at autopsy. <h3>Conclusions:</h3> Patients with PPAOS and a left-dominant pattern of hypometabolism on FDG-PET have the slowest rate of decline of clinical features. <b>Disclosure:</b> Miss Robinson has nothing to disclose. The institution of Joseph Duffy has received research support from NIH. Joseph Duffy has received publishing royalties from a publication relating to health care. Heather Clark has received personal compensation for serving as an employee of Mayo Clinic. The institution of Heather Clark has received research support from NIH. Heather Clark has received publishing royalties from a publication relating to health care. The institution of Rene Utianski has received research support from NIH. The institution of Dr. Machulda has received research support from NIH. Dr. Botha has received research support from NIH. Dr. Singh has nothing to disclose. Nha Trang Thu Pham has received personal compensation for serving as an employee of Mayo Clinic. Mr. Martin has nothing to disclose. The institution of Dr. Taner has received research support from NIH. Dr. Dickson has nothing to disclose. Dr. Lowe has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for AVID Radiopharmaceutical. Dr. Lowe has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Eisai Inc. The institution of Dr. Lowe has received research support from AVID Radiopharmaceuticals. Dr. Whitwell has nothing to disclose. Dr. Josephs has nothing to disclose.