A standard clinical neurological and rheumatological assessment was performed by a physician while observing the participant for any signs of illness behaviour, but no clinical history was taken. The neurological examination included muscle strength testing, examination of muscle tone in arms and legs, coordination including the finger nose test, heel-shin test, heel-toe walking, reflexes and sensation with eyes closed. The rheumatological examination examined joint swelling, wasting of regional muscles, deformity of joint, redness in joints or tendons and the palpation of the margin of joints in hands and feet.
If all the tests were normal with no observed illness behaviour, the patient was classified as not having CFS/ME, whereas if abnormal observations were made, the physician used their clinical experience to decide if the participant had CFS/ME. The physician performing these assessments had experience of working in NHS clinics for CFS/ME but had no experience of the Perrin technique (physician).