Brain stem regulates alertness, arousal, breathing, blood pressure, digestion, heart rate and other autonomic functions. (Lawrence, 2006) It also contains most of the 12 cranial nerves responsible for sensory and motor functions of the face and special senses, meaning hearing, vision, taste, smell and proprioception (balance). One of its significant role to accommodate for the full functioning of nervous system, it relays information between the peripheral nervous system and the central nervous system. (Lawrence, 2006)
Brain stem has been heavily studied due to controversial arguments to clarify the actual meaning of death. The concept of brain death was first described in 1959, it was critical to have substantial evidence to confirm death before harvesting organs for donation. The fundamental definition of brain death has substantively remained constant over time and across countries. One exception is that whereas some countries (e.g., the United States) understand brain death as "whole brain death" others (e.g., the United Kingdom) use the concept of brainstem death. (Wijdicks 2001)
Brain stem functions as mentioned earlier are subject to examination for confirmation of its viability. Hence, the main purpose of eliciting a neurological examination, to pinpoint if there are evidence of life. Recent medical literature suggested that these examinations are done to justify if there is brain death, in simple terms “death”.
Neurologic examination — The examination must demonstrate absent cerebral or brainstem function with all
References: Lawrence, M. Tierney, Stephen, J. McPhee and Maxine, A. Papadakis Current Medical Diagnosis and Treatment 45th Edition 2006 Wijdicks, EFM. Brain Death. Lippincott Williams and Wilkins, Philadelphia 2001. p.175. (2010). Stem Cell Digest.Net. Retrieved from http://www.stemcelldigest.net/stemcell/2010/04/the-cradle-of-new-neurons-in-the-adult-brain-is-the-subventricular-zone-a-tissue-structure-lining-the-lateral-ventricles-th.html