# Measuring memory and concentration after treatment

Source: https://onco.cc/technologies/rejuv-measure-cognitive-function/  
OnCo record `rejuv-measure-cognitive-function` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

What a person notices about their own memory and what a formal test measures are two different things, and they agree only weakly. The questionnaire most used for the first is FACT-Cog; the tests used for the second were standardised by an international task force so that studies could be compared.

## Summary

This is the one area of recovery where self-report alone is not enough, and the field says so.

The questionnaire. FACT-Cog, developed within the FACIT system, asks about perceived cognitive impairments, perceived cognitive abilities, comments from others, and the impact on quality of life. The perceived cognitive impairments subscale is the part most trials report. Work on what a change means used data from a randomised trial of a web-based cognitive training programme in 242 adult cancer survivors who reported cognitive impairment after adjuvant chemotherapy in the previous 6 to 60 months. For the total score the clinically important difference estimates "ranged from 6.1 to 13.2 points", and the estimate from the primary anchor, the EORTC cognitive functioning scale, averaged 10.0 points across two follow-up points. For meaningful change in an individual the same study reports possible thresholds of 14 points from the standard error of measurement and 23 points from the difference between much better and the same.

The tests. The International Cognition and Cancer Task Force published recommendations in 2011 to harmonise studies of cognitive function in people with cancer, because the field was using dozens of different batteries and the results could not be compared. The recommended core covers learning and memory, processing speed and executive function, using tests with published normative data and alternate forms for repeat testing. Separate task force recommendations cover neuroimaging methods and preclinical work.

The gap between the two. Self-reported and objectively measured cognition correlate weakly in cancer populations. That does not mean the self-report is wrong. A person who struggles to follow a conversation may score normally on a test taken in a quiet room with a single task and full attention, because the test does not reproduce the conditions in which the difficulty occurs. It does mean that a trial reporting only one of the two has measured only one of the two, and a reader should check which.

What the measurement still misses. Almost all of this literature is in women with breast cancer, and the FACT-Cog interpretation study says so of its own sample. Fatigue, sleep, anxiety and depression all move cognitive test scores and are not always measured in the same sitting. And there is no agreed definition of a case: whether somebody has cancer-related cognitive impairment depends on which cut-off a study picked.

## Fields

- Kind: Technology
- Status: established
- Last checked: 2026-10-02
- Tags: rejuvenation; survivorship; measurement; instruments; cognition
- Principle: Subjective cognitive complaint and objective neuropsychological performance are separate constructs with weak shared variance. Measuring both, with a validated self-report instrument and a harmonised battery with alternate forms, is the only way to say whether a complaint reflects measurable deficit, measurable deficit without complaint, or neither.
- Since: 2009
- Strengths: A published clinically important difference for the self-report instrument, anchored in survivors; An international harmonised core battery, so studies can be compared; Separate recommendations for imaging and preclinical work in the same framework
- Limitations: Self-report and test performance correlate weakly, so a trial that measures one has not measured the other; Most of the evidence is in women with breast cancer; No agreed threshold for what counts as a case; Fatigue, sleep and mood move test scores and are not always measured alongside

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Post-chemotherapy_cognitive_impairment
- Bell et al., Important differences and meaningful changes for the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) (J Patient Rep Outcomes 2018): https://doi.org/10.1186/s41687-018-0071-4
- Wefel et al., International Cognition and Cancer Task Force recommendations to harmonise studies of cognitive function in patients with cancer (Lancet Oncol 2011): https://doi.org/10.1016/S1470-2045(10)70294-1
- Cella et al., The Functional Assessment of Cancer Therapy scale: development and validation of the general measure (JCO 1993): https://doi.org/10.1200/JCO.1993.11.3.570

## Connected records

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- cancers: [Acute lymphoblastic leukaemia](https://onco.cc/cancers/all-leukemia/), [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- fronts: [Recovery & Rejuvenation](https://onco.cc/fronts/rejuvenation/), [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- terms: [Late effects and survivorship toxicity](https://onco.cc/terms/late-effects/), [Quality of life](https://onco.cc/terms/quality-of-life/)
- bottlenecks: [Patients lack understanding, navigation and agency](https://onco.cc/bottlenecks/b-patient-voice/), [Survivorship and late effects are neglected](https://onco.cc/bottlenecks/b-survivorship/), [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/)

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