An apnea classification system provides for apnea monitoring and differentiation based on several sleep apnea related parameters for diagnostic and therapeutic purposes. Monitoring of such sleep apnea related parameters allows the apnea classification system to differentiate among the different types of apnea and hypopnea and to identify an occurrence of periodic respiration. This information may then be used to determine the best method of therapy, or adjust current therapy parameters to more effectively treat a subject.