Caviness, John N.

The objective of this study was to characterize network-level changes in nonfluent/agrammatic Primary Progressive Aphasia (agPPA) and Primary Progressive Apraxia of Speech (PPAOS) with graph theory (GT) measures derived from scalp electroencephalography (EEG) recordings. EEGs of 15 agPPA and 7 PPAOS patients were collected during relaxed wakefulness with eyes closed (21 electrodes, 10–20 positions, 256 Hz sampling rate, 1–200 Hz bandpass filter). Eight artifact-free, non-overlapping 1024-point epochs were selected. Via Brainwave software, GT weighted connectivity and minimum spanning tree (MST) measures were calculated for theta and upper and lower alpha frequency bands. Differences in GT and MST measures between agPPA and PPAOS were assessed with Wilcoxon rank-sum tests. Of greatest interest, Spearman correlations were computed between behavioral and network measures in all frequency bands across all patients. There were no statistically significant differences in GT or MST measures between agPPA and PPAOS. There were significant correlations between several network and behavioral variables. The correlations demonstrate a relationship between reduced global efficiency and clinical symptom severity (e.g., parkinsonism, AOS). This preliminary, exploratory study demonstrates potential for EEG GT measures to quantify network changes associated with degenerative speech–language disorders.

Recent reports have suggested a high prevalence of olfactory bulb synucleinopathy in Lewy body disorders but there have been no estimates of the sensitivity or specificity of this as a diagnostic test. We performed α‐synuclein immunostaining on paraffin‐embedded sections of olfactory bulb from a series of neuropathologically‐diagnosed subjects from the Sun Health Research Institute Brain Donation Program/Arizona Parkinson's Disease Consortium. Included in the series were 76 normal elderly individuals, 8 subjects with incidental Lewy body disease (ILBD), 63 with Parkinson's disease (PD) and 79 with dementia with Lewy bodies (DLB). Sections were stained with a sensitive method employing pretreatment with proteinase K. The ratios of positive to negative olfactory bulb staining for each diagnostic category were: normal 5/71; ILBD 8/0; PD 57/6; DLB 74/5. An α‐synuclein‐positive olfactory bulb has 92% sensitivity and 93% specificity for the diagnosis of PD versus normal while for DLB it is 94% and 93%, respectively. As all 8 cases of ILBD had a positive olfactory bulb it appears that olfactory bulb synucleinopathy may also be a reliable marker of presymptomatic Lewy body disorders. Supported by the AZ Dept. of Health Services, NIA P30 AG19610 and the Prescott Family Initiative of the Michael J. Fox Foundation.