The Automatic Patient Symptom Monitor (APSM): a voice mail system for clinical research

Abstract

Double-blind clinical trials become very tedious when symptoms are measured rather than objective laboratory and physical parameters. The standard "diary card" method is labor intensive for patients and impractical to use for more than a few weeks. In chronic relapsing disorders it would be far better for patients to record symptoms one or more times per day, at defined times, for weeks, months or even years. The Automatic Patient Symptom Monitor (APSM) is a voice processing system designed to achieve this goal. APSM calls patients at home every night, addresses each patient by name and then asks a set of questions which patients answer by pressing the touch tone keys on their telephone. APSM enters data into a computer database file which can be easily retrieved by investigators, even by modem. In a pilot study, patients with telephones easily learned how to use APSM. They were given therapy for a gastric infection (H.pylori) and were monitored by APSM until follow-up one month after completing treatment. Eight of nine patients recorded valid data on > 80% of study days. In all cases, APSM data matched the patient's own impression of whether they were better, the same, or worse. With one exception, APSM assessment correlated with microbiologic data obtained post therapy i.e. when the gastric infection had been eradicated, patients felt better (p < 0.047). Long term clinical monitoring with APSM may decrease clinical trial time and improve the statistical power of double blind studies.