Explaining coma arousal therapy

Jacqueline Baker
RN, DipTeach(Nsg), BEd(Nsg).

JACQUELINE BAKER is a Lecturer in Nursing Studies at the Sydney College of Advanced Education.

Head injury is a major cause of death and permanent disability. In New South Wales, a report from the Government Insurance Office ¹ indicates that road trauma accounts for 70 percent of cases of severe brain damage and that 50 percent or these occur in the 17 to 25 year age group. The report further indicates that approximately 1,000 people each year are left with a permanent deficit in brain function and that one third will be left seriously disabled for life. These people have often been forgotten, seen as being beyond the help of rehabilitative care. However Ian Hunter, ² in an oral submission to the Parliamentary Social Development Committee inquiry into the options for dying with dignity stated:

It cannot be proven that there is no potential for recovery following brain injury, even in the most severe cases ... because there is no known diagnostic test that can scientifically demonstrate that recovery of function will not occur ... (therefore) every attempt should be made to tap this ...

As a result of this increasing awareness of the potential for recovery, coma arousal programs have developed.

  Coma is: " ... the total absence of awareness of self and environment even when the subject is externally stimulated." ³ Through controversial coma arousal programs it is being shown that even when in a coma a person may be reached through the use of external stimulation. Coma arousal is a planned series of activities aimed at "arousing" a person from a coma.

Physiological theories
  The theoretical underpinnings of coma arousal therapy lie in achieving wakefulness in the patient and capitalizing on the adaptability or plasticity of the brain. Bach-y-Rita ⁴ refers to this adaptability as:

... the adaptive capacities of the central nervous system - its ability to modify its own structural organization and function. It is an adaptive response to functional demand ... plasticity permits enduring functional changes to take place.

There are four scientific theories that address the issue of the brain’s apparent adaptability in recovering from brain injury. These are: spare capacity and reorganization; redundancy; response at a cellular level and environmental effects.

• Spare capacity and reorganization refer to the brain's apparent ability to reorganize its functions following injury. ⁵ The premise of this theory is that many parts of the brain are non-active or "spare", so that when damage to another part of the brain occurs this "spare" area is able to assume the function of the damaged area, thereby compensating for any potential loss of function. Levin ⁶ cites Professor Lorber’s research on people with spina bifida which illustrated this theory. Many of the subjects had cerebral ventricular expansion greater than 90% of the cranium, however over half had IQ scores of greater than 100 and one an IQ of 126 and a first class honours degree in mathematics. It would appear that time is a critical factor if this adaptability is to occur. The slower the insult to the brain, such as a gradual hydrocephalus, the more likely the brain’s ability to adapt.
• The redundancy theory is closely related to the theory of reorganization and refers to the brain’s apparent ability to duplicate neuronal pathways. ⁷ Therefore, if one pathway is damaged the other will be able to take over. Ayers ⁸ believes that this duplication of pathways is the result of evolution and states:
  As the nervous system evolved to meet the expanding needs of existence, the newer structures tended to duplicate older structures and functions, and improve on them rather than to devise different functions ... Thus the same kinds of functions are repeated at several layers of the brain.

These older or redundant pathways, it is believed, may be utilized following injuries that have destroyed the newer pathways.

• The response at a cellular level theory revolves around the scientific fact that when cells in the central nervous system are dead, recovery does not occur. From this has come research on the subsequent effects on cells around the dead area. The work of Lui and Chambers ⁹ in 1958 demonstrated that the undamaged axons of the neurons send out new connections in an attempt to re-wire the system, a process called collateral sprouting. In this way the brain attempts to compensate for its inability to grow new cells.
• The environmental effects theory refers to the improved performance that is noted in animals and humans when increased environmental stimulation occurs. Hunter ¹⁰ cites a number of studies which support the theory. For example, one demonstrated that increased environmental stimulation in rats resulted in greater weight and thickness of the cerebral cortex, ¹¹ and another that it improved performance and increased brain growth in animals. ¹² For ethical reasons studies to date have not been carried out on human subjects, however instances where humans have suffered sensory deprivation have been studied and in most cases serious neurological deficits have resulted. ¹³ Alternatively, a study of institutionalized children found that those who received increased visual and motor stimulation developed skills such as reaching out and grabbing much quicker than those who had not received the stimulation. ¹⁴ Increased stimulation may therefore result in increased ability and brain size. It causes activation of collateral sprouting which in turn absorbs the extra space available and causes a reorganization of the brain's activity.

  Hunter ¹⁵ refers to the process of adaptability as "re-directing the call" and uses the analogy of making a telephone call. For many years the caller has been used to picking up the phone and dialing direct to London. One day the direct dialing system does not work, so the caller goes to the operator to make the connection. The operator also has difficulty making the connection but eventually achieves it via Perth, Hong Kong and Frankfurt. Obviously this takes more time and is more expensive than direct dialing. The caller later finds out that the direct line with London will never work again, so that to call London it will have to be via Perth, Hong Kong and Frankfurt. With time, this more cumbersome method of making the call becomes efficient. Hunter ¹⁶ proposes that this is the same process that occurs in the injured brain: the original connections do not work but through collateral sprouting and the plasticity of the brain the call or message is redirected.

Coma arousal therapy
  The basis of coma arousal therapy lies in the frequency, intensity and duration of environmental stimuli that the patient receives. Stimuli may be via the five sensory modalities (vision, hearing, touch, taste and smell) by which the brain receives information about the outside world  ¹⁷ and physical movement. Sensory stimuli are essential factors in stimulating the reticular activating system (consciousness control centre) to maintain consciousness. ¹⁸

  Basically, any comatose patient in a stable medical condition is a suitable subject for a coma arousal program. Coma mostly results from head trauma sustained in motor vehicle accidents and it is this category of patient most commonly found in coma arousal programs. Patient assessment is essential prior to commencement of the program. Freeman ¹⁹ points out that though it is relatively easy to assess the physiological state, it is difficult to measure the degree of brain function. He believes that the Glasgow Coma Scale (GCS) enables a uniform approach to assessing severe brain injury but questions its value once the patient is scoring above 9; a score of 8 or less out of a total of 15 is usually considered to indicate coma. Due to possible GCS inaccuracy on scores of 9 or above, Freeman suggests that assessment of brain function should involve determining the patient’s visual, auditory and tactile abilities on a continual basis.

  Coma arousal therapy should commence as soon as possible after the development of coma and may start in the intensive care unit providing the person’s medical condition is stable. As will be seen, coma arousal programs are very labour intensive and it has been suggested that the best therapists are those who are interested and caring - frequently relatives or significant others. ²⁰ In addition, those closest to the person are more likely to receive and see a response. As Freeman notes: "Often the relatives have indicated to us that the patient has an awareness which is much greater than we can detect. We listen carefully, because we find them to be right so often."

  The pupillary reflex is the lowest level of visual function, yet as Hunter  ²¹ indicates, although this reflex may not be initiated in the coma patient, it does not necessarily indicate absence of any visual function. He proposes that a light source sufficient to achieve a response (constrict the pupil) may be in the order of 150 watts.

  Having achieved pupil constriction the visual stimulus is changed to include, for example, the use of strobe and flashing lights. Once the patient's eyes remain open flash cards are used. These usually have words or pictures printed on them and should indicate a clear contrast - for example red writing on a yellow background. They are accompanied by a verbal indication of what is printed. In addition, different shapes and colours are introduced.

  The startle reflex is the lowest level of auditory function ²² and as with visual stimulation, the type of response is dependent on the intensity of the stimulus. Noises that might cause conscious people to startle will not stimulate the comatosed. Therefore very loud noises (such as banging two saucepans together, ringing a bell or blowing a loud whistle directly near the patient) are needed to achieve a response. This noise stimulus should be irregular as the brain has the ability to "turn-off" continual sound.

  The third sensory modality, touch, can be achieved by deep pressure massage, pinching and slapping, and use of a vibrator, loofah sponge and brushes is also suggested. ²³ Whatever type of tactile stimulus is used it is important that it be "rough" as the intensity of the stimulus is the important factor in gaining a response.

  Facial grimacing is an indicator that the taste sense is working and like other sensory modalities the intensity of the stimulus is important. Hunter ²⁴ suggests the use of such substances as vinegar, lemon juice, mustard, soy sauce, chilli and salt as an intensive or noxious stimuli. Caution should be employed if the patient has an endotracheal or tracheostomy tube in situ. Smell may be stimulated with the use of peppermint oil, eucalyptus oil, garlic, strong perfumes, rubbing alcohol and spirits of ammonia. ²⁵ Stimulus has been achieved if the patient grimaces or attempts to withdraw.

  The methods outlined are used to achieve some response from the patient to indicate an awareness of the surroundings. At the same time, provided their physical status is stable, mobility stimulus is introduced. Initially, range-of-movement exercises are commenced, eventually progressing to the use of tilt tables. Later the patient is placed on a very large ball in either the prone or supine position to help stimulate balance and head control. Other activities that may be used include rolling the patient from side-to-side on a mat (Figure 1 illustrates some of the movements used).

  The process of coma arousal may be likened to the process a baby goes through in developing an awareness of self and the environment. However the comatosed patient is unable to explore the environment and therefore needs others to present it. It should also be considered that there may be some memory of the environment, which is not so with a baby. Hunter ²⁶ believes that: ". . . frequency, intensity and duration of the stimulus is the most effective means by which the brain can learn . . .", and points to research by Kottke ²⁷ which indicates that to perfect a pattern of coordination required for a specific task, millions of repetitions are required. For this reason the coma arousal program commences at an hour per day, gradually increasing to an intense six to eight hours per day.

  Due to the type of therapy employed and its frequency and duration, arousal programs are labour intensive and time consuming. Therapy is thus usually given by relatives or significant others who have been educated in the process. Professional therapists who have been involved in coma arousal programs emphasize the very positive effects of such involvement. They report that it gives people a sense of purpose, enabling them to channel their efforts and feelings into positive activities.

Implementation by nurses
  As indicated it is believed that early commencement of a coma arousal program greatly increases its success. Nurse therapists who have worked on such a program in Sydney indicate that, although coma arousal therapy is a full time job in itself, there are many ways that nurses functioning in acute or rehabilitative care can implement the principles of coma arousal.

  For many years nurses have been aware of the need to talk to the unconscious patient, however this has often been reflected as a negative concept. For example: ". . . be careful what you say as he might hear and wake up later and remind you." This attitude has often resulted in a lack of verbal stimulation. Nurses have also attempted stimulation through music, but frequently the nurse’s tastes in music has been reflected rather than the patient's. Within some intensive care units music therapy has tended to be on a 24 hours a day basis. A more balanced approach to coma arousal can be affectively achieved if nursing care plans reflect an awareness of the five sensory modalities and mobility as outlined.

  Visual and memory arousal may be achieved by placing bright pictures, posters and familiar photographs in the immediate environment, taking care to ensure that they can be seen in whatever position the patient may be placed. Visual variety is important and sitting the patient in different places in the ward, such as the sitting room, will widen the visual stimulation. Television may also be considered but programs should be selected with regard to the patient’s preference.

  Auditory arousal via music and television should not be constant as the brain has the ability to "turn-off" to regular sound. If disturbing other patients is a problem headphones may be used. Talking about topics that interest the patient may achieve auditory arousal and stimulate the memory. The intensive physical care required means that much time is spent with coma patients. This time provides scope for effective "talk".

  Tactile arousal is achieved in many ways; the level of physical dependency demands a high degree of touch. Such activities as hair washing and bathing, rather than bed sponges, improve tactile stimulation and where possible patients should be dressed. Track suits and sand shoes help stimulate tactile memory, and the use of properly fitting shoes should help reduce the potential for foot-drop. Taste and smell may be stimulated through use of different flavoured mouth cleansing agents, familiar powders, aftershave lotions or perfumes.

  Although the mobility that can be achieved with the comatosed patient within ward areas may be limited, the position should be changed frequently. Mobility activities such as range-of-movement exercises should be explained to promote awareness of the body and its positions. The patient may also be placed on floor mats where they will be free to move or be moved without fear of causing injury. The outside environment offers a tremendous variety of sensory modalities beyond the hospital milieu to which the patient has become accustomed. Where possible consideration should be given to the stimulation that can be achieved in the open air.

  This paper has described the theoretical and physiological underpinnings of coma arousal therapy, methods of stimulating vital sensory modalities and activities that nurses in acute and rehabilitative care areas may employ to implement the principles of such therapy. The road to recovery for the coma patient is slow, hard and tortuous. As such the nurses, other health professionals and families caring for the patient, require great reserves of strength and energy in striving to attain the highest recovery potential, whatever that may be.

  Coma arousal therapy following brain damage is controversial and health professionals remain divided as to its positive effects in improving quality of life. Its effectiveness at this time has not been proved due to difficulties in measuring what may be considered subjective findings. Nevertheless, following brain damage people are left with varying degrees of functional and cognitive deficits, and the continual care and support they require is a significant problem for their families. Any therapy that offers a potential for recovery or improvement, no matter how small, deserves to be attempted, in an endeavour to improve the quality of life of affected persons and their families.

Acknowledgements
I would like to acknowledge the assistance of and express thanks to Ms. Yvonne Ayrey, Ms. Bev Burrell, Dr. Ted Freeman and Mr. Ian Hunter.

References

1. NSW Government Insurance Office Report, A Brain Injury Program for New South Wales, GIO's Committee under Transcover, May 1985.
2. Hunter, I. Oral/written submission to the Parliamentary Social Development Committee, inquiring into the options for dying with dignity, Melbourne, 1986, pp.2.5.
3. Plum, F. and Posner, J.B. The Diagnosis of Stupor and Coma, 3rd edn., Philadelphia, F.A. Davis Co., 1982,p.1.
4. Bach-y-Rita, P. 'Brain plasticity as a basis for therapeutic procedures', in Bach-y-Rita, P. (ed.) Recovery of Function: Theoretical Considerations for Brain Injury Rehabilitation, Vienna, Han Huber Publishers, 1980, p.226.
5. Hunter, I. Brain Injury: Tapping the Potential Within, Melbourne, Hill of Content Publishing Co., 1986,pp.40-44.
6. Lewin, R., 'Is your brain really necessary?', Science, 210:12, December 1980, pp.1232-1234.
7. Hunter, I. op. cit. (5), p.44.
8. Ayers, A.J., Sensory Integration and Learning Disorders, Los Angeles, Western Psychological Services, 1972, p.10.
9. Lui, C.N. and Chambers, W.W.,'Intraspinal sprouting of dorsal route axons', Archives of Neurology and Psychology, 79:6, 1958, pp.46-61.
10. Hunter, I. op. cit. (5), p.47.
11. Rosenzweig, M.R. , Bennett, E.I., and Diamond, M.C., 'Brain changes in response to experience', Scientific American, 226:2, 1972, pp.22-29.
12. Hunter, I. op. cit. (5), p.48.
13. ibid. p.49.
14. ibid. p.49-50.
15. ibid. p.51-53.
16. ibid. p.52.
17. ibid. p 129.
18. Tortora, G.J. and Anagnostakos, N, Principles of Anatomy and Physiology, 3rd edn., Philadelphia, Harper and Row, 1981, p.369.
19. Freeman, E., Coma Arousal Feasibility Study, unpublished, 1984.
20. ibid.
21. Hunter, I. op. cit. p.129.
22. ibid. p.137.
23. ibid. p.133.
24. ibid. p.133.
25. ibid. p.134.
26. ibid. p.114.
27. ibid. p.116.
28. ibid. p.101-102.