Medical devices for the diagnosis and treatment of obstructive sleep apnea and related sleep disorders and component parts and fittings therefor; electrical stimulation apparatus for the treatment of obstructive sleep apnea, namely, an implantable nerve or muscle stimulator made of artificial materials, disposable patch, and a device for implanting the stimulator; activation device for activating implantable electrical nerve or muscle stimulator, activation device for wirelessly activating implantable electrical nerve or muscle stimulator; activation device with rechargeable battery for activating implantable electrical nerve or muscle stimulator; sterile external stimulator for activating the implantable electrical nerve or muscle stimulator; patient screening kits for the diagnosis of sleep apnea and related sleep disorders consisting of a medical device for the diagnosis of obstructive sleep apnea and related sleep disorders, an electronic data recorder for the recording of information collected by the medical device for the diagnosis of obstructive sleep apnea and related sleep disorders, and data management computer software for use with medical devices for the diagnosis of sleep apnea and related sleep disorders, and connection cables for the medical device, all sold as a unit; electrical stimulation system for stimulating upper airway pathways for health and medical purposes