Symptom-based staging for logopenic variant primary progressive aphasia

Abstract

Background and purpose: Logopenic variant primary progressive aphasia (lvPPA) is a major variant presentation of Alzheimer's disease (AD) that signals the importance of communication dysfunction across AD phenotypes. A clinical staging system is lacking for the evolution of AD-associated communication difficulties that could guide diagnosis and care planning. Our aim was to create a symptom-based staging scheme for lvPPA, identifying functional milestones relevant to the broader AD spectrum.

Methods: An international lvPPA caregiver cohort was surveyed on symptom development under an 'exploratory' survey (34 UK caregivers). Feedback from this survey informed the development of a 'consolidation' survey (27 UK, 10 Australian caregivers) in which caregivers were presented with six provisional clinical stages and feedback was analysed using a mixed-methods approach.

Results: Six clinical stages were endorsed. Early symptoms included word-finding difficulty, with loss of message comprehension and speech intelligibility signalling later-stage progression. Additionally, problems with hearing in noise, memory and route-finding were prominent early non-verbal symptoms. 'Milestone' symptoms were identified that anticipate daily-life functional transitions and care needs.

Conclusions: This work introduces a new symptom-based staging scheme for lvPPA, and highlights milestone symptoms that could inform future clinical scales for anticipating and managing communication dysfunction across the AD spectrum.

Keywords: Alzheimer's disease; logopenic; primary progressive aphasia; staging.

FIGURE 1

Symptom frequencies and confidence in symptom placement by clinical stage for logopenic variant primary progressive aphasia. A symptom was retained only if a majority (at least 50%) of caregivers who provided a response to a given symptom reported it was present at some stage of the illness (see Appendix S1, Table S2, for complete symptom list). Boxes on the left‐hand side denote stages, numbered 1 (very mild) to 6 (profound). Written symptom labels and bars are colour‐coded based on domains of verbal communication (grey scale) and non‐verbal functioning (non‐verbal cognition and behaviour, red; personal care and well‐being, blue). Horizontal bars indicate the percentage of respondents to a given symptom who indicated that symptom to be ‘present’, with subdivisions of each bar reflecting the proportion of respondents indicating that symptom to be present at a specific stage. Percentages in the ‘confidence’ column were calculated as the percentage of people who had responded that a given symptom was present who endorsed placement of that symptom in its final stage (i.e., the highest agreement achieved for placement of that symptom); this varied across stages (stage 1 mean average, 73%; stage 2, 66%; stage 3, 53%; stage 4, 61%; stage 5, 69%; stage 6, 86%). Symptoms have been ordered within stages in descending order of overall frequency.