Many medical alarm devices are small transmitters allowing the person in need to call for help, generally being automatically patched through to an operator. But a panic button on the other hand simply has to press the button for help to be soon at hand. This could be in the form of an ambulance or friends/family or even a local doctor who'd be assigned to you.

What does this mean for the individual, how is it better if they cannot speak?
For a start it would receive far more immediate attention than if you were using a normal speaker device. In that scenario you would have to tell the operator you needed emergency services - and in that time you could already have lost alot of blood. Remember that if you were injured, you would be in shock - imagine trying to calmly tell the operator what was going on if you were bleeding all over the floor.

There are other reasons as well, such as the elderly person being unintelligible to the operator. Again, imagine trying to communicate if you had a respiratory disease from for example smoking - which many elderly people do have. It would be very difficult and crucial seconds which could make all the difference between life and death would be lost.

The button on the hand would allow instantly the pre-organised actions to be taken. This could be a family member elsewhere in the house being called in - or even the emergency services automatically being called to the house. An emergency medical panic button is definitely very helpful. However, what would cover all possibilities is both a panic button and a medical alarm device transmitter. This would allow the injured individual to request either instant help, or to receive less extreme and immanent help.