A timed test of swallowing capacity has been designed for use in patients with neurogenic dysphagia. Swallowing speed (mlls) has been demonstrated to have high intra-and inter-rater and test-retest reliability, and to be essentially independent of flavour or temperature. "Guideline" normal values were established in individuals without a swallowing disorder: swallowing speed was less in females than males and declined in both groups with age. obtain an adequate view of laryngeal movement during each swallow so that the number of swallows can be counted. The time and number of swallows taken from the "go" signal to the last swallow recognised by return of the larynx to the rest position (as seen exteriorly by the movement of the thyroid cartilage) are noted. Any coughing during or after the test and the quality of the voice after the test is noted. The residual volume is measured in those in whom the test is abandoned so that in all cases speed (ml/s), and average volume/ swallow (ml) are calculated. Such a test is clearly inappropriate in patients with major dysphagia who are obviously aspirating.2) Reliability studies Intra-rater reliability was assessed by one examiner timing twice the videotaped record of the swallows undertaken by six normal subjects or patients in random order and with the stopwatch face obscured. Inter-rater reliability was examined by 6 observers observing videos of swallowing tests on five normal subjects or patients. The possibility of a learning effect was tested in 24 normal subjects by repeating the test in each subject 4 times over a 48 hour period: at the same time the effect of flavouring the drink was assessed by randomising the order of the 4 drinks-2 of which were water and two a flavoured drink. The effect of temperature on swallowing speed was studied by presenting water at three different temperatures (9°C, 19°C, 39°C) in random order to 6 normal subjects. Finally, swallowing speed was measured twice, at an interval of 1 to 37 days, in 38 neurological patients, of whom 24 had abnormal swallowing speeds (see below).3) Guideline normal ranges A swallowing test was undertaken in 101 "normal" subjects to establish a guideline range for swallowing speed. Individuals with clinically relevant medical or swallowing disorders were excluded.

Swallowing was studied prospectively in a consecutive group of 90 neurology outpatients under 70 years of age. No patient had been referred primarily because of dysphagia. Patients were classified into four groups: those with (1) neurological or (2) non-neurological diagnoses possibly relevant to disordered swallowing, (3) functional disorders, and (4) definite diagnoses not likely to be relevant. They were defined as having abnormal or probably abnormal swallowing if two or more of the following were present: a complaint of swallowing problem, abnormal symptoms or signs, a slow swallowing speed (< 10 ml.s-1). Nineteen patients among the four groups (21%) were found to have abnormal/probably abnormal swallowing. Swallowing speed was significantly slower in patients who perceived a swallowing problem or who had abnormal symptoms or signs compared with those who did not, providing further evidence for the validity of a timed test of swallowing capacity. The study also provides evidence of a significant incidence of disordered swallowing in outpatients who may not have complained spontaneously but who have diagnoses potentially relevant to swallowing.

Recurrent aspiration and dysphagia may be the only initial symptoms in an adult presenting with an Arnold Chiari type I malformation.