COMA STIMULATION IN TBI: RATIONALE, GOALS, PRINCIPLES, AND TECHNIQUES OF COMA STIMULATION

Rationale and Goals

  • May affect the RAS and increase arousal and attention to the level necessary to perceive incoming stimuli
  • May prevent environmental (sensory) deprivation, which has been shown to retard recovery and the development of central nervous function and further depress impaired brain functioning
  • Allows for frequent monitoring of patient's responsiveness
  • May improve the quantity and quality of responses toward purposeful activity
  • May provide opportunities for the patient to respond to the environment in an adaptive way
  • May heighten the patients' responses to sensory stimuli and eventually channel them into meaningful activity

Principles of Coma Stimulation

  • Do no harm. Before starting any stimulation, check resting vital signs (heart rate, blood pressure, and respiratory rate).
  • Avoid or minimize stimulation programs with comatose patients that have a ventriculostomy when increased intracranial pressure (ICP) and/or cerebral perfusion pressure (CPP) are still issues; monitor ICP and CPP during and after treatment if necessary
  • Control the environment to eliminate as many distractions as possible. The environment should be simple and uncluttered, with a limited number of people around the patient, and with the TV off and the door closed during treatment
  • Make sure the patient is as comfortable as possible before starting; tubes, restraints, etc. may interfere with the stimulation.
  • Organize the stimuli, present them in an orderly manner, and involve only 1 or 2 modalities of senses at a time. It is important to control how much and how often to provide stimulation, because patients can "habituate" or get used to the stimulation, in which case the stimulation can become less meaningful.
  • Explain to the patient before and while the stimuli are presented
  • Allow extra time for the patient to respond (because of slow information processing). 1 or 2 minutes between the administration of different stimuli is useful as an initial guide until the length of response delay is established
  • Keep sessions relatively brief - patients can usually tolerate up to 15-30 minutes
  • Conduct sessions frequently, allowing patients to respond several times daily, but alternating periods of stimulation with periods of rest
  • Select meaningful stimuli, such as voice of family and friends, favorite music, cologne, etc. Stimuli that have emotional significance to the patient are usually more likely to elicit responses
  • Verbally reinforce responses to increase the likelihood of obtaining responses in later sessions
  • Try stimulating all the senses, and vary the stimuli in nature and intensity to maximize the possibility of increasing arousal. Do an ongoing evaluation of stimuli to which the patient responds, as well as those to which the patient does not respond
  • To improve the quality and quantity of responses as responsiveness increases, direct treatment toward increasing the frequency and rate of response, the period of time that patient can maintain alertness, the variety of responses, and the quality of attention to the environment
  • Avoid overstimulation, indicated by flushing of the skin, perspiration, agitation, eye closing, sudden decrease in arousal level, increase in muscle tone, and prolonged increase in respiration rate, by alternating periods of stimulation with periods of rest
  • Include participation by family and significant others in the coma stimulation program

Techniques of Coma Stimulation

  • Approaching the Patient
    • Identify yourself
    • Talk to the patient slowly, and in a normal tone of voice
    • Keep sentences short and give the patient extra time to think about what you've said
    • Orient patient to the date, time, place, and reason for being in the hospital, and explain to the patient what you are going to do

  • Visual Stimulation
    • Provide a visually stimulating environment at the bedside, such as colorful, familiar objects, family photographs (labeled), and TV 10-15 minutes at a time
    • Provide normal visual orientation, by positioning patient upright in bed, in the wheelchair, etc. This also helps decrease complications of prolonged bedrest, such as pressure sores, breathing problems, osteoporosis, and muscle contractures
    • Eliminate distraction to allow patient to focus on visual stimuli, such as a familiar face, object, photos, and on a mirror
    • Attempt visual tracking after focusing is established, i.e. getting the patient to follow a stimulus with his/her eyes at it moves. Tracking usually begins in the center or midline.

  • Auditory Stimulation
    • Provide regular auditory stimulation at the patient's bedside. All hospital staff should be encouraged to speak to the patient as they work in the room or directly with the patient. An information sheet can be posted in the room with information about the patient's likes and dislikes
    • Permit only one person to speak at a time
    • Use radio, TV, tape recording of a familiar voice, etc. for 10-15 minutes at intervals throughout the day
    • Direct work to focusing and localizing sound and look for patient's response when you change the location of a sound, e.g. call the patient's name, clap you hands, ring a bell, rattle, whistle, etc. 5-10 seconds at a time
    • Avoid stimulation that evokes a startled response. This type of stimulation is counterproductive.

  • Touch Stimulation - Tactile input can be facilitory (encourage a desired response) or inhibitory (discourage/interfere with a desired response). For example, pain and light touch to the skin tend to produce an inhibitory response, while maintained touch, pressure to the oral area, and slow stroking of the spine tend to produce a facilitory response. The face, and especially the lips and mouth area, are the most sensitive.
    • Use a variety of textures, such as personal clothing, blankets, stuffed animals, lotions, etc.
    • Use a variety of temperatures, such as warm and cold cloths or metal spoons dipped for 30 seconds in hot or cold water
    • Vary the degree of pressure - firm pressure is usually less threatening or irritating to the patient than light touch. Examples include grasping a muscle and maintaining the pressure for 3 -5 seconds, stretching a tendon and maintaining the stretch for a few seconds, and rubbing the sternum
    • Use unpleasant stimuli, such as a pinprick, with caution. Avoid ice to face or body, as it may trigger a sympathetic nervous system response, i.e. increased blood pressure, heart rate, and salivation and decreased gastrointestinal activity

  • Movement Stimulation
    • Use range of motion exercises, changes in body position such as a single or repetitive roll, a tilt table to bring the patient to a more upright position, and movement activities on a therapy mat
    • Watch for early physical protective reactions or delayed balance reactions during these activities

  • Position Stimulation - Slow changes in position tend to be inhibitory, while faster movement patterns tend to facilitate arousal
    • Monitor the patient's blood pressure (and ICP if appropriate) during this stimulation
    • Use position changes that are meaningful and familiar, such as rolling, rocking in a chair or on a mat, and moving from lying down to sitting
    • Avoid spinning, which may trigger seizures, and mechanical input, such as raising and lowering the hospital bed, which has little functional meaning and produces limited response

  • Smell Stimulation
    • Use after shave, cologne, perfume, favored extracts, coffee grinds, shampoo, and favorite foods
    • Provide the stimuli for no more than 10 seconds
    • Avoid touching the skin with the scent, because patient may accommodate the scent and be less responsive to it
    • Use garlic and mustard as noxious stimuli
    • Avoid vinegar and ammonia because they irritate the trigeminal nerve

    However, there may not be a response to smell stimulation because:

    • The olfactory nerve is the most commonly injured cranial nerve in TBI
    • Many TBI patients have tracheostomies, which eliminate the exchange of air through the nostrils and therefore inhibit the sense of smell
    • Patients have nasogastric tubes in place, which block one nostril and therefore decrease the sense of smell

  • Taste and Oral Stimulation
    • Provide taste stimulation, unless patient is prone to aspiration - Use a cotton swab dipped in a sweet, salty, or sour solution, but avoid sweet tastes if the patient has difficulty managing oral secretions since sweet tastes increase salivation
    • Provide oral stimulation during routine mouth care, unless patient demonstrates a bite reflex
      • Use a sponge-tipped or glycerin swab or a soft toothbrush to diminish hypersensitivity and abnormal oral/facial reflexes
      • Use a flavored cleansing agent, such as mint or lemon, to increase oral stimulation during routine mouth care.
    • Provide stimulation to the lips and area around the mouth. If patient demonstrates defensiveness to touch, such as pursing lips, closing mouth, or pulling away from the stimulus, gently continue with stimulation techniques to decrease defensive reactions and increase level of awareness. Do not attempt feeding of patients in coma.

Based on Brain Injury Patient Care and Education Manual, by Pinecrest Rehabilitation Hospital; Neuro section of the Trauma Manual, Jackson Memorial Hospital; and Recovering from Head Injury; a Guide for Patients, by Nova University Neuropsychology Service, and edited for PoinTIS by the Louis Calder Memorial Library of the University of Miami School of Medicine and the PoinTIS Advisory Committee, and on Rehabilitation of Persons with Traumatic Brain Injury, NIH Consensus Statement 1998 Oct. 26-28.