inputs such as but not limited to data obtained from sensing electrodes 10 a 10 b 10 c and 10 d one or more electrocardiograms u201c ecgs u201d response button responsiveness test results voice recognition responsiveness test results etc preferably the processing unit 15 is configured so that treatment is not delivered unless the confidence algorithm determines that there is a 100 confidence that the patient is experiencing a life threatening arrhythmia the one or more audio devices 16 may be configured to identify whether background noise exists in the event no or little background noise is sensed the confidence in the detection can be increased the processing unit 15 may also be configured to permit the delivery of treatment to be accelerated if no background noise or little background noise is detected by the one or more audio devices 16 the processing unit 15 may be configured to delay a delivery of treatment if a high level of background noise is identified because significant background noise may reduce the quality of the data obtained by the electrodes 10 a 10 b 10 c or 10 d for example the quality of ecg sensing electrodes may be reduced with significant background.