A method for treating a subject is provided where at least two types of electrical stimulation are provided to cause diaphragm contraction. At least one type of stimulation is configured to bias lung volume of a subject. The stimulation method may include without being limited to a method to treat a subject having neuromuscular impairment of the diaphragm. The stimulation method may also include without being limited to a method to treat a subject who has been diagnosed with central sleep apnea.