modality - a method of therapy that involves physical or electrical therapeutic treatment. rehabilitation - the treatment of physical disabilities by massage and electrotherapy and exercises.
Alkaline AA batteries are rated 1.5 volts, while NiMH AA batteries are rated at 1.2 volts. NiMH generally refers to a battery being rechargeable and to the materials from which the battery is constructed.
Also, it is not likely that your battery is ever completely dead. Even when the battery is discharged it can still have upwards of 9 volts. If you put a voltmeter on a battery and you get a reading of 0 volts, then you may very well just need a new battery. The fact is though that 95% of batteries are never fully discharged when they need a jump start.