Language indicators of change of diagnosis in nonfluent-variant primary progressive aphasia
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1
University of Sydney, Australia
Nonfluent-variant primary progressive aphasia (nfvPPA) is characterized by prominent effortful, halting speech and/or agrammatism. While the hallmark features of nfvPPA are predominantly language and speech impairment, clinically some nfvPPA patients develop extrapyramidal symptoms such as slowness and rigidity of movement and limb apraxia. Indeed, with disease progression, some nfvPPA patients change diagnosis, particularly to corticobasal syndrome and progressive supranuclear palsy.
Methods: Here we aimed to determine the extent that nfvPPA patients change diagnosis, and in patients who have a revised clinical diagnosis, identify the clinical and neuropsychological signs at presentation which are suggestive of a future change in diagnosis. Sixty-seven patients were initially diagnosed with nfvPPA at the FRONTIER dementia clinic in Sydney between 2007 and 2018. All patients underwent assessment by a behavioural neurologist, MRI, and neuropsychological testing. Thirty-nine patients were followed-up at least once. Participants who did not undergo review were older (p = .002), less educated (p = .007), had longer disease duration (p = .001), and were at a more severe disease stage, as measured by the Frontotemporal dementia Rating Scale (p = .012).
Results: At follow-up 71.8% of patients (n = 28) still met criteria for nfvPPA. Of the remainder, considerable heterogeneity was observed in the revised diagnosis. Notably, the most common was a change to a diagnosis of frontotemporal dementia with motor neurone disease (FTD-MND), which occurred in 12.8% of patients (n = 5). A further 12.8% of patients were either diagnosed with corticobasal syndrome (n = 2) or progressive supranuclear palsy (n = 3). The remaining case was reclassified as logopenic-variant primary progressive aphasia (n = 1). Demographics did not differ between nfvPPA patients whose diagnosis changed and those whose diagnosis stayed consistent. Examination of patients’ initial neurological assessment indicated that syntactic errors were more common in patients who did not change (p = .026), whereas difficulties with sentence repetition tended to be more common in patients who changed diagnosis (p = .052). Formal neuropsychological testing revealed patients who changed diagnosis had worse visuospatial function (Rey Complex Figure copy, p = .046), and tended to have better digit span (p = .070) and marginally poorer basic face perception (p = .092) than patients who did not change diagnosis.
Conclusions: Our results demonstrate that even in specialist clinics around 30% of nfvPPA patients who are reviewed have changed diagnosis. Unexpectedly, the most common change was to FTD-MND, which warrants further investigation. Importantly, presence of syntactic errors and lower digit span are indicative of nfvPPA, whereas more widespread cognitive impairment (sentence repetition, visuospatial dysfunction and impaired basic face perception) indicates a potential change in diagnosis. Longitudinal studies are essential to improve our understanding of prognosis in this complex syndrome, and to ultimately refine diagnostic criteria. Future analyses will examine clinicopathological associations in this cohort.
Acknowledgements
The authors are grateful to all the patients and their families for supporting our research. We would also like to thank Michelle Fu for assistance in data preparation. This work was supported by the National Health and Medical Research Council (NHMRC) (GNT1037746; GNT1121791). FK is supported by an NHMRC-ARC Dementia Research Development Fellowship (GNT1097026). OP is supported by an NHMRC Senior Research Fellowship (GNT1103258).
Keywords:
FTD (Fronto-Temporal Dementia),
Sentence repetition,
syntax,
diagnosis,
Nonfluent primary progressive aphasia
Conference:
Academy of Aphasia 57th Annual Meeting, Macau, Macao, SAR China, 27 Oct - 29 Oct, 2019.
Presentation Type:
Platform presentation
Topic:
Not eligible for student award
Citation:
Kumfor
F,
Ballard
KJ,
Burrell
JR,
Hodges
JR and
Piguet
O
(2019). Language indicators of change of diagnosis in nonfluent-variant primary progressive aphasia.
Front. Hum. Neurosci.
Conference Abstract:
Academy of Aphasia 57th Annual Meeting.
doi: 10.3389/conf.fnhum.2019.01.00008
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Received:
22 Apr 2019;
Published Online:
09 Oct 2019.
*
Correspondence:
Dr. Fiona Kumfor, University of Sydney, Sydney, Australia, fiona.kumfor@sydney.edu.au