Cognitive Functioning and Rehabilitation
Odie Bracy PhD
The purpose of this article is to present a way of looking at and conceptualizing brain functioning that will aid in the diagnosis and treatment of brain dysfunction. The theory discussed here will be presented, somewhat in terms of physiological functioning, but mostly, in terms of:
- the skills that must be present for normal functioning,
- how some of these skills may be affected by neurological disorder or injury and
- what might be done in treatment that can affect these skills and thereby enhance functioning.
The brain is the center of being and all of its functions have the collective purpose of maintaining and nurturing that state of being. The body and its life support systems, the senses and the movement systems are at the same time, an extension of the brain and a servant to the brain for the purpose of providing for and meeting the needs of the whole system. At the most basic levels of existence, a being must be equipped to obtain and take in nourishment, protect itself from danger and the forces of nature, and reproduce. Though the means and methods of insuring that these basic needs are met have evolved to complex systems in these modern times, when you cut through the glitz and glitter we are still simply pursuing those same basic needs. To accomplish these necessities for life, each being must be able to "know" when its needs require fulfillment or action, be able to conceive of the appropriate actions that will resolve the need and then be able to carry out those actions. For the purposes of this article, I will concentrate primarily on those functions that gather information, process information, generate ideas and solutions, generate and carry out responses, and store and retrieve these occurrences.
Interfacing With Self and The World Through the Senses
The brain requires information about the body and about the world outside of the body. The sensory system is the brain's interface or means by which it is possible to collect that information. Located at the sensing end of each sensory subsystem are specialized receptor cells. Each type of these specialized cells responds to specific conditions or changes in conditions. The reaction or response of the cell to the stimulus condition or change encodes the information that then represents the situation. Nerves and nerve tracts extend from the sensory receptor cells to transport this information that can then be utilized peripherally (i.e., away from the brain) and/or transported to more central points and the brain. From within the body itself, information can take the form of muscle states, body position, temperature, pain, discomfort, body chemistry, blood gases, hunger and numerous other physiological states. Other sensory interfaces to the self and the world include vision, hearing, touch, taste, smell, etc.. All of this information and much more is constantly being received and transported for processing by higher nervous systems. Fortunately, we do not have to consciously think about or even have awareness of the processing of most of this information. Some of our nervous systems are set up to directly handle the information and make adjustments automatically. That still leaves an overwhelming amount of constantly incoming information that requires a great deal of processing in order to be interpreted, understood and utilized.
The mechanisms directly responsible for sensing can be manipulated and influenced in limited ways by outside intervention. To some extent these functions can be enhanced by chemistry (i.e., medications), but largely they can be more easily dampened or made temporarily dysfunctional by these means. Some sensory mechanisms can be artificially supplemented such as by the use of glasses or hearing aids. Some sensory mechanism losses can be compensated for by other sensory mechanisms as seen with deaf persons who visually read lips or use sign language. However, generally speaking, when injury or disease directly affects a mechanism of sensation, there is relatively little that can be done to restore it.
There do seem to be states or situations from within the individual that can have an effect of enhancing or dampening the flow of sensory information. The level of arousal or excitement and the intensity of emotion being experienced at any given moment by an individual can greatly affect the threshold of sensory experience. The current activity in which an individual is already engaged, likewise, can influence the sensory experience. Past experience also seems to have the potential for predisposing one to greater or lesser sensitivity. While, restoration of impaired sensation may not then be a treatment consideration, enhancement of the sensory experience through indirect manipulation of states of arousal, excitement and emotion or increasing sensitivity through experience may well be.
Information Processing
The sensory receptor and transporting mechanisms operate pretty much continuously, delivering an unimaginable amount of information to the brain. At the various points of arrival, the information is still relatively pure and specific to the content of the original message, which may have actually been put together through the combined effort of a great number of closely grouped receptor cells. Information from some systems and parts of information from other systems undergo some form of processing by lower brain centers such that signals might be combined, separated, enhanced or diminished. Some lower brain centers operate such that the job performed there is triggered simply by reaction to the incoming signals without having to process them further. Many body functions are regulated and needs met by actions, reactions, and responses to incoming information at these lower brain levels where it is not necessary for the person to consciously think about or even be aware of what is going on.
The Executive Skills
Pure and partially processed information is transported further to higher brain levels, eventually arriving at specialized receiving sites in subcortical and cortical areas. It is at this point that additional interfaces are required to bring the information into consciousness, decode it, integrate it, form thoughts and images of it, manipulate it and utilize it. The collective group of skills engaged in this monumental task as well as other tasks, that will be presented later, are referred to as the Executive Skills. I will refer to this whole group of skills as the Executive as I discuss specific skill subgroups that make up the Executive, but have very specialized duties.
The Executive Skills of Attention
The first group of skills are those that contribute to the interface needed to properly receive and utilize information arriving from the sensory mechanisms. Not all of the information arriving at the brain is important information. The importance of specific aspects of information may vary depending on the state of the whole person or the life situation that the person is currently experiencing. The group of skills required at this stage must be able to do the following:
1. Constantly monitor incoming information.
2. Recognize what is important.
3. Focus on what is important and monitor it as a foreground activity.
4. Continue monitoring other information as a background activity.
5. Shift what is foreground and background as appropriate.
6. Maintain focus for the extent of the event.
7. Share focus with multiple events as required.
The subgroups of skills engaged in these functions are referred to as the Attentional Skills. It is my opinion that there are more than one set of attentional skills operating simultaneously and, in fact, there may be an independent subset of attentional skills for each modality of sensory experience. The Executive then integrates and combines the work product of the attentional skill subgroups to form a whole life experience gestalt or mental image and utilizes a master set of attention skills to interface with the gestalt. Conceived of in this way, the whole list of required attentional functions above is required for processing each sensory modality individually and again by the master attentional skill group for analysis and processing of the gestalt formed from the integration of all of the individual sensory experiences. More involved attentional skills of tracking, scanning and searching can be brought into action by and under the direction of the Executive.
A breakdown or dysfunction at the level of the sensory mechanism or along the pathway to the brain will result in loss of or distortion of sensory information. Even if intact information is arriving at the brain, dysfunction within the attentional skill subgroup may result in inability to utilize the information, or only partially use the information. Further distortion, loss or misperception of information can be produced by faulty attention skills from overemphasis or mingling of unimportant information. Dysfunction of the master attentional skills can produce distortion of the gestalt or mental image even when intact information is available.
The Executive Skills of Information Processing
All of the proceedings discussed to this point are continuously happening. Rather than being like single snapshots, the nature of these skills and work product must be more like that of movie film. While there is a great deal of information that could be processed and utilized when viewed from the snapshot perspective, there is much more involved in the whole matter from the movie film perspective. This perspective is more than a sequence of snapshots. The analysis is not simply of each frame, but also of the similarities and differences from frame to frame. The final gestalt, through this kind of analysis, includes a conception of not just how things are now, but of how things are evolving. The time based or temporal characteristics of sensory experience are then brought into the mental experience.
Other skills of the Executive in addition to those of attention are required to form and work with this mental image I am referring to as the gestalt. Perceptual skills are the basic tools for gestalt formation. These are the executive skills that attach meaning to the work product of the attentional skills, while at the same time provide motivation and direction back to the attentional skills by influencing the level of importance placed on incoming information. Perception implies that the incoming information has been added to the gestalt in a manner that characteristics of the state, event or object perceived, are accurately portrayed in the mental image. Perceptual to its fullest extent also implies that a set of knowledge about the state, event or object is also incorporated into the mental image. However, there can be many levels of perception represented and associated with from great sets of knowledge, to sets of very little knowledge. The smaller the set of existing knowledge, the more novel the perception would be. The novelty of a perception is of itself highly motivating and can shift a set of incoming information into a big focus priority category.
Perceptions are not necessarily correct portrayals of states, events and objects and are subject to update and correction. Incomplete knowledge sets can slant perceptions which in turn slant gestalts. So, there is much room for misinterpretation, misunderstanding and subsequent error in thoughts or actions that are based upon faulty gestalts formed with misperceptions.
Formulating thoughts and implementing actions are the highest level of activity of the Executive. Basic to this is the handling of incoming information and the formation of the mental gestalt. The Executive works to form perceptions with the information passed on from the attention skills. In order to accomplish this, the Executive must be able to analyze and discriminate the information from a number of perspectives and finally relate the products of this analysis to past experience. The work product of these activities is the perception, and the techniques of analysis can include among others, the following:
1. Separating,
2. Combining,
3. Sorting,
4. Ranking,
5. Sequencing,
6. Categorizing,
7. Grouping.
The perception can be considered as a small gestalt that combines with a number of other perceptions to form the whole gestalt or mental image. The master group of attentional skills can work with all or parts of the whole gestalt to allow the executive to focus on, attend to, and monitor any or all of the whole mental image.
The Executive Skills of Thought and Conceptualization
With demands, needs, wants and desires serving as motivational forces and influences, the Executive seeks solutions. With the current real life mental image as a picture of the situation requiring action, the past experiences, successes and failures from stored memory as models of possible solutions, and the ability to generate new attempts at solution, the Executive forms a concept. This concept can be thought of as the Executive's formulation of what a future real life gestalt might be if the actions of the solution are implemented. The concept can be simple or elaborate. Much consideration can go into its formulation with the Executive playing the steps through over and over, refining and reformulating before implementation, or the concept could be quickly put together and implemented without such consideration.
The implementation of solutions will be discussed later, but at this point while still in the areas of attention, perception and conception, we should take a look at another aspect of these functions. In order to learn and add to the existing sets of knowledge, in order to control the behavior of the person and in order to properly and accurately implement programs of action, the Executive must track and monitor the perceptions, conceptions and programs of actions it formulates, utilizing all of the skills mentioned thus far to accomplish this. The activities of the Executive then come full cycle. Additional analytical skills are required to recognize the effects of the ideas and actions, then to recognize the level of success of these to accomplish the solution and to recognize when to start and stop the action, or to change or modify the ideas and/or the actions. The incoming information directly related to an action or solution can be referred to as feedback. Without being able to process feedback, recognize this type of information as such, profit from it by reanalyzing the program of action and modify the program based upon the feedback and reanalysis, a person would have very little success in interacting with the environment or others and in accomplishing the goals of meeting needs. A person lacking ability in these areas may have trouble initiating and inhibiting actions and their behavior may appear self-centered, insensitive, inflexible and narrow minded.
The Qualities of Information
Information being processed by the Executive possesses attributes to some degree from each of the four primary dimensions of being verbal, spatial, temporal and physiological in nature. The quality of being verbal is unique in that for the most part, verbal information actually represents some other experience, event, gestalt, or solution. Rather than being important in and of itself, verbal information is mostly important for the coded information within it. The cerebral or cognitive skills of interest to us in this area of functioning are the abilities to decode the information, comprehend the messages, appreciate the messages on multiple levels (i.e., its purely factual content, its emotionality, its intention, its feedback properties, etc.), utilize the verbal information in formulating our own perceptions, concepts and gestalts, and encode our messages for transmission to others.
The spatial quality of incoming information helps us orient ourselves to the rest of the world and to the position and state of our own body and its parts. This type of information is essential for accurate movement interaction with anything outside our bodies and for forming a conception of our relationship with the world around us.
The temporal quality of information and existence is intertwined with and forms a frame for the other qualities of information. It provides a means of order, sequence and evolution that the Executive incorporates into its analysis. It provides a means for being able to predict future interactions and possible outcomes.
The physiological quality of information helps the body system to sustain the activities of life, but in addition, it provides a means of motivation, judgement and reaction that offers a unique contribution to our functioning. This unique contribution is in the form of feelings and emotions. It is a sometimes ambiguous, but persuasive, contribution that can sway executive decisions even in the face of contradicting more factual executive analysis.
The Implementation of Actions and Solutions
There are only two systems for use by the Executive to produce action or reaction. One of these is the chemical system of the body. It has its direct effect primarily within the body rather than with the world. However, indirectly, changes in the chemical balance can manifest in the motivational and emotional systems and through this avenue influence decisions and behaviors.
The second system is the motor or muscular system. Even the sounds of speech are nothing more than a highly coordinated and complex production of the musculature of the abdomen, chest, larynx, throat, tongue and lips. Much of the brain appears to be involved, through the Executive, in the planning and implementation of the muscular excitation and inhibition required for even the simplest of movements. Rather than the brain having to think of and plan every minute component of every single movement all of the time, it is more likely that templates, patterns or programs of movement exist that are formulated from experiences, that date back to infancy. These templates or programs are stored somewhere within the brain and are sequenced and combined together to play out the action conceived of and implemented by the Executive. Some portions of the brain then serve to run and coordinate the programs, insuring proper sequencing, smooth transitions among the parts and smooth execution of the movements. Other areas, under the guidance of the Executive as it processes feedback information, change and modify the templates as necessary to play out the Executive's directives.
When conceived of in this manner, it is easier to understand the many anomalies of movement seen in persons with compromised brain functions. Compromise anywhere along the system could cause unique changes in abilities (i.e., the apraxias) or varying degrees of loss of ability.
Memory
Memory consists of those sets of cerebral skills and functions that store and retrieve information. I won't get into attempts to explain how it works or where it is located, but will discuss the skills and functions. Memory is often separated into the three categories of remote, recent and immediate, with time being the primary differential among the classifications. There must be a time factor involved in the transition of a memory through these categories or stages since interference with the process by injury, for example, will often result in a situation in which there is no recall for the event or, in some cases, for events preceding the injury. Other factors, present when the information was introduced into memory or at some time associated with the memory, such as emotion or great meaning or crisis will serve to strengthen the memory, in clarity, detail and ease of retrieval.
Some refer to memory according to the quality of the information contained in the memory such that memories are referred to as being visual memory, spatial memory, verbal memory, etc. This implies that there are separate memory systems or areas for these different types of information. I am inclined to think that this is not the case. Memory seems to get blamed every time a person cannot retrieve information that they think they should. In many cases the breakdown is in the sensory, attention, perception and executive skills so that the information never actually got into the system so that it could have been stored. When memory is being tested in any of these category areas, to a large extent it is the sensory, attention, perception and executive skills that are being tested. There are, I believe, separate systems within these skills for receiving and processing the different types of information. Faulty functioning within the spatial information processing system then would lead to faulty information of a spatial nature being stored. Later upon retrieval, this person might appear to have an impairment of spatial memory. If it could first be shown that the different types of information were being received and processed correctly, and afterward that memory specific to a modality was impaired, then the ideas of separate modality specific memory systems would be more plausible. I think that whole gestalts are stored as memories and that modality specific impairments in the information intake and processing systems distort those specific contributions to the gestalt. When the gestalt is recalled, the distortion is evident, but often mislabeled as a memory problem.
The skills and functions of memory can be impaired, as we well know. However, when I have seen people who exhibit a true impairment of memory, the impairment appears to affect the recall of all aspects of the semantic information or experience. Frequently, procedural memory (i.e. knowing how to do something, although one cannot verbalize it) remains somewhat to mostly intact and continues to function even for new procedures. The skills and functions that belong to the specific area of memory functioning are those that:
1. Store the gestalt utilizing some type of complex tagging or random access filing system,
2. Those that maintain the memory, and
3. Those that can, with very little in the way of keywords, cues or clues, accurately retrieve the stored gestalt.
When memories are retrieved, some executive processing must occur to incorporate the retrieved information into the current gestalt. Here lies another possible source of distortion of the retrieved information. Once again, modality specific impairment within the attention, perception and executive systems can distort specific qualities of the retrieved gestalt. Therefore, memories that may have been recalled intact many times before may be distorted following compromise to the brain when actually the memory may still be intact, but the processing of it upon retrieval was faulty.
These distinctions among the possible sources of distortion and/or breakdown are important because I think there are very real and different implications for rehabilitation dependent upon the source of the compromise.
Rehabilitation
Although I consider the brain to be infinitely more complex than a computer and would not dare to propose that one is a more or less complex version of the other, there are some comparisons of certain characteristics and attributes that are illustrative and meaningful. If we think of the nature of the brain's functions along the lines of the computer's modes and means of operation for a moment, it might serve a useful purpose. The whole operating computer is a combination of both hardware and software activities. The hardware operations are set, constant functions that start when the system is turned on and operate fairly continuously, consistently and in a set manner until turned off or modified. Some hardware operations can be modified by other hardware operations directly and some can be modified by software to some extent. Software (which is programmed and alterable) is actually the basis of how and by which the computer does what it does. Software programs are solutions designed to overcome a need of or demand on the programmer.
Brain functions, skills and operations can be classified along a similar continuum from being more hardware in nature, to being more software in nature. To the extent that a brain skill or function is more software than hardware in nature, then it will be more amenable to change with and from experience. I think that to a large extent the attentional skills and some aspects of the executive, perceptual and conceptual skills are acquired, developed, and programmed skills. These skills should be amenable to change through experience and should therefore be amenable to the proper efforts of rehabilitation. Other brain functions are more like hardware based skills such that once they are altered or lost, the change is very likely permanent. Sensations (i.e., vision, hearing, touch, etc.) and certain functions of memory, speech and motor skills would fall into this category. Part of our work in performing diagnostic examinations on our patients with compromised brain functioning then would be to determine what may or may not be amenable to rehabilitation retraining experiences. For those areas of functioning thought to be retrainable, we should be able to accomplish the retraining by providing the correct experiences and by making the appropriate demands upon the compromised person such that the person would have to develop the skills or functions to overcome or satisfy the demands. The therapy experiences must take into account the many different areas and levels of functioning within all the areas described in this article. Clear, accurate and instant feedback must be provided by the exercise and the complexity of the exercise must be carefully gauged to be at the borderline between current ability and the next higher level being pursued. Our excursion along the pathways of development as infants and children was years in the process. There is no reason to expect that retraining and rehabilitation can be accomplished overnight, when in fact it might take months to years to reacquire skills, while some skills lost to injury, insult or disease may never be re-acquired.