From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history
- 71.6% - 75.1% of the 2073 patients in a Belgian study of 2001 reported difficulty with calculations.
- Katrina Berne reports a prevalence of 75-80% for 'aphasia' (inability to find the right word, saying the wrong word) and/or dyscalculia (difficulty with numbers) - although she notes that this symptom is probably underreported and more prevalent than indicated.
- De Becker, P; McGregor, N; De Meirleir, K (Sep 2001), "A definition-based analysis of symptoms in a large cohort of patients with chronic fatigue syndrome.", Journal of Internal Medicine, 250 (3): 234-240, PMID 11555128
- Berne, Katrina (1 Dec 1995), Running on Empty: The Complete Guide to Chronic Fatigue Syndrome (CFIDS), 2nd ed., Hunter House, p. 59, ISBN 978-0897931915