We read with great interest the Review by Henry on prospective memory (PM) impairment in neurological disorders (Henry, J. D. Prospective memory impairment in neurological disorders: implications and management. Nat. Rev. Neurol. https://doi.org/10.1038/s41582-021-00472-1 (2021))1. The author outlines the frequent occurrence of PM impairments in various neurological disorders, with a focus on PM assessment. Specifically, the author proposes that “self-report measures often correlate weakly with objective assessments” and “single-item PM tests have lower reliability and sensitivity than clinical batteries.”

Recent literature reviews have highlighted the flaws of clinical batteries and emphasized the relevance of questionnaires and single-item PM tests. In a systematic and meta-analytic review of PM assessment tools2, Blondelle and colleagues highlighted the lack of standardized neuropsychological evaluation in clinical practice. The authors showed that many PM tools lacked normative data, cut-off scores for diagnostic purposes, qualitative scoring, parallel versions and/or ecological validity. Although translated versions of some tools exist, there is a distinct lack of cultural adaptation in non-WEIRD (Western, educated, industrialized, rich and democratic) populations3, and progress in this area will rely on following specific guidelines for test development4. Performance-based measures (so-called objective assessments) are valuable for clinical practice, but we should not forget the work needed to make these tools available and relevant to each patient.

With the current focus on performance-based measures, it would be regrettable if single-item PM tests were disregarded. Although we acknowledge that the Key Task is of limited clinical interest, the Envelope Task is interesting to spot patients with dementia5 and is sensitive enough to detect difficulties associated with amnestic mild cognitive impairment6. In these scenarios at least, continued incorporation of this measure into routine clinical practice could be warranted.

We agree with Henry’s point of view regarding the weak correlation between self-report and performance-based measures, and that the former measures “should supplement rather than replace a formal behavioural assessment.” However, a recent scoping review7 argues that self-report and informant-report PM measures evaluate different constructs from those targeted by performance-based tests, and can also sometimes aid the distinction between individuals with and without PM impairment7. Sugden et al. also pointed out the importance of self-report measures to assess the impact of interventions. As such, self-report and informant-report measures seem to represent metacognitive measures of the concerns of individuals about their PM ability rather than measures of PM performance per se.

Finally, in addition to the neurological disorders discussed in the Henry Review1, researchers and clinicians should be aware that PM impairments are also found in patients with rare conditions such as spina bifida meningomyelocele8 and transient global amnesia9.

There is a reply to this letter by Henry, J. D. Reply to: Assessing prospective memory beyond experimental tasks. Nat. Rev. Neurol. https://doi.org/10.1038/s41582-021-00501-z (2021).