When the person is left alone, access to a telephone is important. Land lines in some geographical areas are connected with emergency services with the address of the caller posted on each service's screen. Dialling 911, 000 or 999 will bring help if the person can reach the phone.
Portable alarm buttons that people can wear and notify services if the person is unconscious are currently available but expensive. Portable buttons that require being conscious to push the button are not as expensive.