Dyscalculia

Dyscalculia is the medical term for experiencing severe difficulty in making arithmetical calculations, as a result of a brain disorder.

Prevalence

 * 2001, In a Belgian study, 71.6% of patients meeting the Fukuda criteria and 75.1% of patients meeting the Holmes criteria, in a cohort of 2073 CFS patients, reported a personality change.
 * 1995, Katrina Berne, PhD, reported 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.