Clinical measurement of swallowing in health and in neurogenic dysphagia

We studied clinical features potentially related to dysphagia and three indices from a timed test of swallowing--average volume per swallow (ml), average time (s) per swallow and swallowing capacity (ml/s)--in 181 screened healthy adults and 30 patients with motor neurone disease (MND). In healthy adults, age, sex and height accounted for 44.3% and 55.6% of the variance of log average volume per swallow and log swallowing capacity, respectively. Symptoms and signs were more prevalent in the MND group and were associated with reduced swallowing capacity and reduced average volume per swallow; repeatability studies on these two indices in both groups showed that the median difference between the mean of two recordings on successive days and the mean of all recordings (6-15 over 3 days) was < 5% (maximum third quartile 12.8%, indices expressed as percent predicted according to age and sex). Using this simple bedside test, swallowing function can be quantified on a ratio scale and expressed as percent of that predicted by age and sex; such information may improve the predictive value of clinical assessment and provides a practical way of monitoring change in patients with dysphagia.