Are there any recorded cases of hearing the outside world while in a coma? There are plenty of stories flying around of people having been in a coma, but able to hear the outside world. They usually include either hearing malicious things said by staff, or encouragement by loved ones.
Are any of these cases recorded and verified, not just apocryphal?
Here's a study on Brain Response to One's Own Name in Vegetative State, Minimally Conscious State, and Locked-in Syndrome:
http://archneur.jamanetwork.com/article.aspx?articleid=791093


  Background  A major challenge in the management of severely
  brain-injured patients with altered states of consciousness is to
  estimate their residual perception of the environment.
  
  Objective  To investigate the integrity of detection of one's own name
  in patients in a behaviorally well-documented vegetative state (VS),
  patients in a minimally conscious state (MCS), and patients with
  locked-in syndrome.
  
  Design  We recorded the auditory evoked potentials to the patient's
  own name and to 7 other equiprobable first names in 15 brain-damaged
  patients.
  
  Results  A P3 component was observed in response to the patient's name
  in all patients with locked-in syndrome, in all MCS patients, and in 3
  of 5 patients in a VS. P3 latency was significantly (P&lt;.05) delayed
  for MCS and VS patients compared with healthy volunteers.
  
  Conclusions  These results suggest that partially preserved semantic
  processing could be observed in noncommunicative brain-damaged
  patients, notably for the detection of salient stimuli, such as the
  subject's own name. This function seems delayed in MCS and (if
  present) in VS patients. More important, a P3 response does not
  necessarily reflect conscious perception and cannot be used to
  differentiate VS from MCS patients.