Word-deafness phenotype in logopenic variant primary progressive aphasia: A multicenter retrospective case series.

BACKGROUND

PPA-variant attribution of the clinically overt word-deafness phenotype remains incompletely characterized. Word deafness has been described across PPA phenotypes, but published reports often emphasize nonfluent/agrammatic variant PPA (naPPA); group-level auditory studies have not addressed clinically recognized presentations dominated by difficulty understanding speech. We aimed to identify patients meeting prespecified criteria for this phenotype and describe their adjudicated PPA-variant diagnoses.

METHODS

We retrospectively screened 109 patients with PPA from six centers (2012-2025) using a three-step algorithm: (1) symptom-driven screening (listening difficulty, frequent requests for repetition, auditory-written dissociation on the Japanese Western Aphasia Battery); (2) exclusion of severe peripheral hearing loss by pure-tone audiometry; and (3) audiological corroboration of disproportionate speech-perception impairment on speech audiometry.

RESULTS

Eight patients screened positive; two were excluded for severe peripheral hearing loss, and the remaining six fulfilled criteria, all adjudicated as logopenic variant PPA (lvPPA). Listening difficulty emerged early and prompted otolaryngologic evaluation in five patients. Despite normal-to-mildly elevated pure-tone thresholds, speech audiometry showed markedly reduced discrimination scores in all cases. Auditory brainstem responses were preserved when tested; the Two-Burst Fusion Test was abnormal in one tested patient. Neuroimaging showed temporoparietal-predominant involvement compatible with lvPPA.

CONCLUSIONS

Word deafness may occur across PPA phenotypes. In this symptom-driven series, all clinically recognized, audiologically corroborated cases were lvPPA, though the design does not permit prevalence estimates across variants. Clinicians should consider this phenotype across PPA variants, rather than assuming naPPA alone, when patients present with disproportionate difficulty understanding speech despite preserved pure-tone hearing.