Consecutive patients with CFS who met the Fukuda criteria  for CFS were all seen by a single physician (RB). Patients with any medical condition which could account for chronic fatigue, a BMI > 30, previous GI surgery or medication affecting the rate of gastric emptying were excluded. Overt psychiatric disease was excluded at the interview. The patients were asked to self assess their percentage reduction in activity from prior to the onset of CFS as a marker of severity. Gastro-Intestinal symptoms were evaluated in patients and controls by a standard questionnaire prior to the gastric emptying studies .
Symptoms were divided into "oesophageal" (dysphagia, heart burn, acid regurgitation), "gastric": (anorexia, nausea, early satiety, bloating, abdominal distension, intermittent abdominal pain), "other" frequency of bowel actions, consistency of stools, presence or absence of diarrhoea, urgency and timing.
Symptoms were scored. 0, none, 1, mild (symptom could be ignored), 2, moderate (symptom could not be ignored, but did not influence daily activities), 3, severe, (symptom influenced daily activities). A mean symptom score (maximum score 3) for the 6 gastric symptoms, and 3 oesophageal symptoms was obtained.
The volunteer control subjects who completed the questionnaire were in regular full time employment, with no history of excessive fatigue, on no GI medication, and had no previous GI surgery.
Radionuclide measurement of upper GI motility
Details and normal ranges of this double isotope test have been previously published . The solid meal consisted of 100 g of cooked ground beef containing 40MBq in-vivo labelled 99mTc-sulfur colloid-chicken liver, and the liquid meal consisted of 150 ml of 10% dextrose in water containing with 20 MBq of 67Ga-ethylenediaminetetraacetic acid (EDTA). All medication (except oral contraceptives) was discontinued for 24 hours prior to each study. The test was performed at 10 am (after an overnight fast) and monitored for at least two hours with the subject in the sitting position with the scintillation camera behind. The study commenced with a standardised oesophageal clearance study (solid bolus) followed by eating the solid meal and then immediately drinking the glucose solution. Each study was continued for at least 2 hours. Oesophageal clearance was expressed as time to 95% clearance (ref range < 93 sec) , Liquid gastric emptying as half-clearance time (ref 4–31 minutes) and solid emptying as amount remaining at 100 min (ref 4–61%).
The GI questionnaires were compared between CFS and control by Chi2, and Gastric emptying indices compared with historical normal range (t test comparison of means), and correlated with the mean symptom score (± SD).
The Study was approved by The Human Research Ethics Committee of the Royal Adelaide Hospital and informed consent given by the subjects.