biostudies-literatureSintini INIDCD NIH HHS105-116https://www.ebi.ac.uk/biostudies/studies/S-EPMC9613616biostudies-literatureUnknown120Primary progressive apraxia of speech (PPAOS) is a neurodegenerative motor speech disorder affecting the ability to produce speech. If agrammatic aphasia is present, it can be referred to as the non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA). We investigated whether resting-state functional MRI (rs-fMRI) connectivity from disease "epicenters" correlated with longitudinal gray matter atrophy and hypometabolism in nfvPPA and PPAOS. Eighteen nfvPPA and 23 PPAOS patients underwent clinical assessment, structural MRI, rs-fMRI, and [¹⁸F] fluorodeoxyglucose (FDG)-PET at baseline and ∼2 years follow-up. Rates of neurodegeneration in nfvPPA and PPAOS correlated with functional connectivity to the premotor, motor, and frontal cortex. Connectivity to the caudate and thalamus was more strongly associated with rates of hypometabolism than atrophy. Connectivity to the left Broca's area was more strongly associated with rates of atrophy and hypometabolism in nfvPPA. Finally, functional connectivity to a network of regions, and not to a single epicenter, correlated with rates of neurodegeneration in PPAOS and nfvPPA, suggesting similar biological mechanisms driving disease progression, with regional differences related to language.Neurobiology of agingFunctional connectivity to the premotor cortex maps onto longitudinal brain neurodegeneration in progressive apraxia of speech.PMC9613616R01 DC012519R01 DC010367R01 DC014942Josephs KAJack CRDuffy JRBotha HSchwarz CGMachulda MMWhitwell JLStrand EASintini IUtianski RLClark HMLowe VJSenjem MLfalseFunctional connectivity to the premotor cortex maps onto longitudinal brain neurodegeneration in progressive apraxia of speech.Primary progressive apraxia of speech (PPAOS) is a neurodegenerative motor speech disorder affecting the ability to produce speech. If agrammatic aphasia is present, it can be referred to as the non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA). We investigated whether resting-state functional MRI (rs-fMRI) connectivity from disease "epicenters" correlated with longitudinal gray matter atrophy and hypometabolism in nfvPPA and PPAOS. Eighteen nfvPPA and 23 PPAOS patients underwent clinical assessment, structural MRI, rs-fMRI, and [¹⁸F] fluorodeoxyglucose (FDG)-PET at baseline and ∼2 years follow-up. Rates of neurodegeneration in nfvPPA and PPAOS correlated with functional connectivity to the premotor, motor, and frontal cortex. Connectivity to the caudate and thalamus was more strongly associated with rates of hypometabolism than atrophy. Connectivity to the left Broca's area was more strongly associated with rates of atrophy and hypometabolism in nfvPPA. Finally, functional connectivity to a network of regions, and not to a single epicenter, correlated with rates of neurodegeneration in PPAOS and nfvPPA, suggesting similar biological mechanisms driving disease progression, with regional differences related to language.2022-01-01T00:00:00Z2022 Dec2025-04-26T09:51:59.823Z2025-04-06T13:08:22.67ZS-EPMC96136163616691810.1016/j.neurobiolaging.2022.08.013