The most common massage cushion we think of is the electronic type. These devices provide a back massage when placed upright against the back of a massage chair. Typical features will include multiple speeds or variable force from the massage mechanism, as well as different modes of movement and heat. While these are no substitute for the real thing, a well-made electric massage cushion can provide relief for straightforward and mild aches and pains.
Quality matters when purchasing any piece of electronic equipment, but particularly with a massage cushion. It should have a robust design and be capable of exerting a fair degree of force. Don't be won over by fancy graphics on a box or celebrity endorsements. You want a product that is recognized and endorsed by the medical establishment. It should also come with a comprehensive warranty.
Another type of cushion doesn't provide massage but may keep you from needing therapy in the first place. These are cushions used to support correct posture and body positioning. Examples include lumbar rolls used when you drive, or shaped pillows for between your knees when you are in bed. Many people with back trouble carry a back support cushion with them wherever they go - for instance in the bath. It should be noted, though, that this isn't the kind of thing one should self-diagnose. While these types of cushions may relieve unpleasant symptoms, they are not a cure. In some cases, a well-developed exercise program, combined with weight loss, may improve your health to the point that you no longer need most of these kinds of devices. Some of the aches and pains we experience as we age are preventable and curable, and often the former is better than the latter.
A third category of massage cushions are ones that are purchased by professional therapists for use with clients. A flat massage table isn't always the most comfortable way to treat a client. Modular pillows can be fitted to the human body to provide more support and improve the ability of the patient to relax during treatment.