Chapter 3 Theoretical Conceptualisation of Attention and Motor Activity
From the previous chapter it emerged that AD/HD may possibly be illusive. Does it exist only because of the fact that we can compare behaviour to the criteria as set by the DSM-IV? Is there enough evidence to suggest that there is a definite neurological dysfunction? When is attention ineffective and motor activity inappropriate?
To be able to answer these and other questions surrounding the topic, it is necessary to explore the fundamental conceptualisation of attention and motor activity. A rational point of departure in answering these questions is the central nervous systems (CNS) and its involvement in attention and motor activity, and more specifically, the brain’s role. This framework may assist in formulating possible solutions and methods of intervention as the development of the CNS and specifically the brain follows a basic pattern through the use of movement. The CNS also requires specific substances (nutrients) to assist in its optimal development and maintain optimal performance. When deviations in this fundamental developmental process are detected and the result points to attentional difficulties and heightened motor activity, a possible solution presents itself. Could a neurodevelopmental programme based on movement address attentional difficulties and heightened motor activity? Could nutritional supplementation assist attention and motor activity? This chapter investigates these issues to form a framework for understanding the constructs that form the cornerstones of the diagnosis of AD/HD, namely attention and motor activity.The history of the efforts to unravel the source of human consciousness is well documented in Robbins’ (2000:9-28) book: A Symphony in the Brain. This history goes back thousands of years and a brief summary is presented here.
Hundreds of ancient skulls with carefully drilled holes have been found in a variety of places around the world. Even though humankind explored the content of the cranium cavity, the Egyptians reserved the heart as the dwelling place of the human soul (for most of the human history, a cardiocentric view has dominated). Writings between 460 and 379 B.C. indicate that Hippocrates might have been the first persuasive proponent of the idea that the brain is the source of human intelligence. Building on the work of two of his teachers, Alcmaeon and Anaxagoras, he had the notion that epilepsy was the result of a disturbance in the brain. He believed that the grey matter was also the source of many other human experiences:
Men ought to know that from nothing else but the brain come joys, delights, laughter and sports and sorrows and grief, despondency, and lamentations. And by this, in an especial manner, we acquire wisdom and knowledge, and see and hear and know what are foul and what are fair, what are bad and what are good, and what are sweet and what are unsavoury. And by the same organ we become mad and delirious, and fears and terrors assail us. All these things we endure from the brain, when it is not healthy. In these ways I am of the opinion that the brain exercises the greatest power in the man. This is the interpreter to us of those things, which emanate from the air, when the brain happens to be in a sound state.
(Cited in Robbins 2000:11)
Hippocrate’s view, however, was unique among his peers, too far ahead of its time to be taken seriously. Even Aristotle, who came along several decades later, was a primary proponent of the heart-centred human.
Galen, a physician to Roman gladiators and emperors in the second century, played a major role in the evolution of early thought about the brain. His cell doctrine reigned for fifteen hundred years, largely because, from the fourth through to the fourteenth century, the church banned study of the human body. In the seventeenth century, Thomas Willis, an English physician, published a thorough text on the anatomy of the brain in which he claimed that the brain itself, and not the ventricles, controlled memory and volition. His work sparked a new way of thinking and would later convince researchers to abandon the cell doctrine. Yet the cell doctrine survived for years after Willis’s findings. René Descartes, the influential seventeenth-century French philosopher, is one of the most dominant early figures in the study of human behaviour. Descartes promoted the idea of dualism, the idea that mind and body are separate. Descartes chose the pineal gland as the place where the spirit entered the body, because it occupied a central place in the brain, because it was near the senses, and because it was surrounded by cerebrospinal fluid, which was still believed to be the liquid version of the animal spirits that allowed the body to move. Descartes’ interpretation was the first attempt to assign a specific task to a specific part of the brain.
After the invention of the microscope, brain research developed rapidly. Chemical dyes, created for the textile industry, were used to dye slices of brain tissue for study under the newly invented instrument. The microscope lent itself to the next evolutionary step in thinking about the brain, the school of localisation. Researchers looking at cross sections of brain tissue noticed that different parts of the brain had different types and numbers of cells and asked whether this difference in structure – the cytoarchitecture – pointed to a difference in function.
Localisation gained substantial scientific support in 1861 as a result of the research of the respected French physician Paul Broca. Broca worked with a stroke patient who seemed to hear clearly but could only answer any question asked with a single word: “tan”. After the patient died, Broca removed his brain and found a large lesion on the part of the organ called the posterior frontal cortex, on the left side of the head near the temple. Broca hypothesised that this small region of the brain – now called Broca’s area – enabled humans to speak. His research rocked the medical world and kicked off a search for functions across the whole brain.
Not long after, a German neurologist named Carl Wernicke discovered another area of the brain involved in speech, further to the rear of the brain than Broca’s area, and named it Wernicke’s area. Wernicke also came up with a model of how speech is assembled by networks in the brain, a model that still holds up and provides some understanding into the complex nature and interrelated functions of the brain. Two Englishmen, Charles Beevor and Victor Horsley, mainly conducted the research that followed and provided a detailed map of the functions of every section of the brain.
In the 1880s an Italian anatomist named Camillo Golgi developed a new stain that made nerve cells much easier to study under the microscope. This was a fundamental development, for it had previously been impossible to enhance the microscopic cell without killing it. Using the new stain, a Spanish anatomist named Santiago Ramony Cajal revolutionalised the world of neuroscience when he discovered the brain cell, the neuron. These discoveries earned Golgi and Cajal the Nobel Prize in 1906. Until then the human brain had been thought of as just a grey mass. Cajal also described the way cells pass on impulses, by reaching out to the group of dendrites of an adjacent cell with a kind of cable called an axon. He went on to make several other major discoveries about brain cells, including the fact that nerve cells morph or change. This is particularly significant in the light of our current knowledge of the brain’s plasticity, including that movement and stimulation may affect the plasticity positively. (This fact has huge implications for therapy and will be explored in further chapters of this study.) After the discovery of the neuron, Hans Berger, a physicist, expanded our knowledge on the physiology of the brain by adding the concept of electrical impulses.
The field of neuroscience continues to actively explore the brain and its capacities. The systems that govern the human brain are the most complex and compact on earth, and even though more has been learned about the brain in the last twenty years than in all of human history, science has not come close to understanding how all the pieces fit together to create human consciousness.
In this chapter, the traditional concepts of attention and motor activity will be discussed against this backdrop. This will lay the groundwork for a comprehensive understanding of attentional difficulties and heightened motor activity, the two most prevalent aspects of the AD/HD diagnosis.
There are a number of different theories and findings on attention. All attempt to delineate the areas of the brain (school of localisation) that are primarily involved in attention, as well as explain the function of these areas to produce and sustain attention. Needless to say, the theories do not always correspond. This section will thus present a few different perspectives.
According to Johnston and Dark (cited in Lezak 1995:19), a clear and universally accepted definition of attention has not yet appeared in the literature. They postulate that attention can rather be conceptualised as “several different capacities or processes that are related aspects of how the organism becomes receptive to stimuli and how it may begin processing incoming or attended-to excitation [whether internal or external]” (Lezak 1995:19). The notion of exactly how widely divergent definitions of attention are may be best illustrated by Mirsky’s (cited in Lezak 1995:20) placement of attention within the broader category of information processing, and Gazzaniga’s (1987) conclusion that “the attention system … functions independently of information processing activities and [not as] … an emergent property of an ongoing processing system” (Lezak 1995:21).
Some researchers have, however, attempted to define attention more specifically. According to William James, attention could be defined as “the taking possession of the mind, in clear and vivid form, of one out of what seem simultaneously possible objects or trains of thought … It implies withdrawal from some things in order to deal effectively with others” (cited in Sternberg 1999:68).
Sternberg (1999:68) himself defines attention as the means by which we actively process a limited amount of information from the enormous amount of information available through our senses, our stored memories, and our other cognitive processes. It includes both conscious and unconscious processes. The content of attention may reside either within or outside of awareness.
He continues to say that, by dimming the lights on many stimuli from outside (sensation) and inside (thoughts and memories), we may highlight the stimuli that interest us. This heightened focus increases the likelihood that we may respond speedily and accurately to interesting stimuli. Heightened attention also paves the way for memory processes so that we are more likely to remember information that we paid attention to than to information we have ignored.
Many researchers emphasise one or more of the characteristics that William James (cited in Lezak 1995:22) ascribes to attention. These include the capacity for disengagement to shift focus the capacity to be responsive to either sensory or semantic stimuli characteristics Additional characteristics of attention have been described as follows:
sustained tonic attention as it occurs in vigilance, where tonic refers to the type of cognitive processing which requires slow, serial effort and which is affected by the under-production of dopamine phasic attention, which orients the organism to changing stimuli, where phasic attention refers to processing that is fast and simultaneous (Lezak 1995:23).
Lezak (1995:27) concludes that most researchers conceive attention as a system in which processing occurs sequentially in a series of stages within different brain systems involved. This system appears to be organised in a hierarchical manner in which the earliest entries are modality specific (i.e., visual, auditory, tactile, etc.) while late-stage processing – for example, at the level of awareness – is supramodal (cortical). Disorders of attention may arise from lesions involving any point in the system.
Another salient characteristic of the attentional system is its limited capacity (Lezak 1995:29). Only so much processing activity may take place at any one time, so that engagement of the system in processing one attentional task requiring controlled attention may interfere with a second task with similar processing requirements.
Attentional capacities vary not only between individuals but also within each person at different times, under different conditions. Depression or fatigue, for example, may temporarily reduce it in intact adults; old age and brain damage may reduce attentional capacity more lastingly. Simple immediate span of attention, with the capacity for information than may be grasped at once, is a relatively effortless process that tends to be resistant to the effects of ageing and of many brain disorders. Immediate attention span may thus be considered a form of working memory, although it is an integral component of attentional functioning as a whole (Lezak 1995:30-31).
Models of Attention and Concentration
Different models of attention exist. Within these models researchers attempt to explain attention in terms of the mechanisms that are involved. A few of these are explored in the following section.
The attention circuit
Winston (2004:152) briefly explains the attention circuit as a process of focusing on information before we can use it, and involves several brain areas locked in a circuit. The thalamus relays sensory information to the appropriate part of the brain’s cortex for processing. The information then enters short-term memory and is stored in the prefrontal cortex. The parietal lobes are also involved. The ability to shift attention is as important as the ability to focus, as without it a person will be unreceptive to new sensory input and so unable to adapt quickly to new situations.
Three-element theory of attention (Thompson and Thompson)
Thompson and Thompson (2003:114-115) give an overview of the three-element theory of attention in their book: The Neurofeedback Book. A short summary of this model is presented here:
Arousal involves reticular activating system (RAS) activity. The nerve fibres from this system stretch as far as the frontal cortex. These fibres control consciousness, sleep/wake cycles, and the general level of activity in the brain. The axons activating the prefrontal lobe release dopamine and noradrenaline, which is followed by beta brainwave activity. Beta is the brainwave bandwidth that facilitates attention (see chapter 5 section 2.3 for an explanation of these concepts).
Orientation involves the superior colliculus (the area of the brain that stimulates the muscles that turn the eyes) and parietal neuronal activity to disengage attention from the current stimulus. To some extent the eyes direct attention to new stimuli and the brain inhibits attention to previous stimuli in order to free itself for new incoming stimuli.
The lateral pulvinar nucleus in the thalamus operates like a spotlight shining on the stimulus, locking onto it and sending information about the target to the frontal lobes, which then lock on and maintain attention, together with the eyes (as in the orientation phase).
An important part that has not been included in this theory by Thompson and Thompson is the role of the cerebellum and the interaction between the cerebellum and the RAS. Their model does, however, include the involvement of other brain areas in attention such as the superior colliculus and the thalamus. The role of neurotransmitters and brainwave activity are also included in the model.
A model of concentration (Levinson)
Levinson describes his view of attention in his book Total concentration (1990:46-56). He states that in our daily lives, we are constantly bombarded by more information that we can possibly handle, comprehend, absorb, or process. As a result, we are forced to select information and activities out of all the stimulation that surrounds us. This often occurs on a moment-to-moment basis. Two basic functions allow us the opportunity to be able to cope with the demand for attention. These are selective attention and selective intention.
He states that “although many researchers have attempted to define the process of selective attention, I prefer to describe it as the dual ability to focus on what’s important and to simultaneously filter out what’s not” Levinson (1990:56). Levinson believes selective attention comprises eight specific steps that are analogous to the act of turning on and watching a television set. Non-clinical individuals without a concentration dysfunction report that the process feels automatic and that they are unaware of the fact that they are moving through these steps. When the process of selective attention is intact, individual is capable of paying attention and can accomplish tasks that require attention. When, however, the process of selective attention becomes impaired, individuals are not able to pay attention adequately. Individuals are then forced to compensate, consciously and deliberately, by attempting to re-learn the missing steps. Typically this process requires training in modification intervention sessions.
According to Levinson, there are two parallel but interrelated mechanisms responsible for modulating and implementing the process of selective attention:
The reflexive, automatic determining mechanism (unconscious). This mechanism is inner ear-based (vestibular) and is also responsible for regulating all sensory-motor-related academic processes.
The second mechanism is conscious and deliberate (intentional) and is determined by higher order cerebral or thinking functions.
Combined, these two concepts form the basis of functional concentration. Under normal circumstances, these two neuropsychological determinants of selective attention are completely interconnected and interwoven via feedback circuits, and thus act as one indivisible whole. In the presence of attentional difficulties, the functional unity of these two determining mechanisms becomes detached and thus clinically apparent. Compensatory processes (intervention) focusing on and enhancing either the vestibular and/or cerebral mechanisms facilitate a reunification of the whole process. A dysfunction in selective attention is characterised by ‘improper tuning’, distractibility, wandering focus, and reduced response to feedback, making self-correction difficult.
Even before the individual begins to create something, a certain amount of planning is required. This activity, called selective intention, assists in anticipating the outcome of the action and in selecting the best ways to accomplish a task.
According to Levinson (1990:65), these two processes (selective attention and selective intention) need to be fully functional in themselves, and when combined are fundamental to the ability to concentrate completely.
Levinson’s emphasis on the role of the vestibular system in attention again suggests that movement may be implicated in this process since the vestibular system develops through movement, and movements are co-orinated by the vestibular system. Levinson, like Thompson and Thompson, does not mention the vestibular-cerebellum connection. It is well documented that these two structures are fundamentally linked (Ito 1984, 1987; Goddard 1996). Levinson does include the involvement of the frontal lobe in attention in his model, thereby indicating that attention is an unconscious as well as a conscious process.
Conscious attention (Sternberg)
According to Sternberg (1999:80-84), there are three main functions of conscious attention:
signal detection, including vigilance and search, in which we must detect the appearance of a particular stimulus selective attention, in which we choose to attend to some stimuli and to ignore others divided attention, in which we prudently allocate our available attentional resources to coordinate our performance of more than one task at a time
Signal detection theory was one of the first theories to suggest an interaction between the physical sensation of a stimuli and cognitive processes such as decision making. According to signal-detection theory (SDT), there are four possible outcomes of an attempt to detect a signal or a target stimulus.
correct positive (hit), in which the subject correctly identifies the presence of a target false positive (false alarm), in which the subject incorrectly identifies the presence of a target that is actually absent false negatives (misses), in which the subject incorrectly fail to observe the presence of a target correct negative (correct rejection), in which the subject correctly identify the absence of a target.
Usually, the presence of a target is difficult to detect, so the individual makes decisions based on inconclusive information, with some criteria for target detection.
Vigilance refers to a person’s ability to attend to a field of stimulation over a prolonged period of time, in which the person seeks to detect a particular target stimulus. When being vigilant, the individual watchfully waits to detect a signal stimulus that may appear at any time. Typically, vigilance is needed in settings where a given stimulus occurs only rarely but requires immediate attention as soon as it does. Vigilance may thus be seen as a form of sustained attention.
The difference between vigilance and search can mainly be compared in terms of the level of activity required from the subject. Whereas vigilance involves passively waiting for a signal stimulus to appear, search involves actively seeking out a target. Search refers specifically to scanning the environment for particular features; in other words, actively looking for something without being sure of where it will appear. In both instances, the subject may, whilst searching for something, respond by making false alarms. In the case of a search, false alarms usually arise when the subject encounters distractions (non-target stimuli that divert the attention away from the target stimulus) while searching for the target stimulus. The number of targets and distracters affects the difficulty of the task.
According to Sternberg, people use selective attention to track one message and simultaneously ignore others. Auditory selective attention may be observed by asking a participant to shadow information presented dichotically (both ears at same time, different messages). In essence, the subject is required to pay attention to one message only. Visual selective attention may be observed in tasks involving the Stroop effect.
Specific attentional processes are also involved during divided attention, when people attempt to handle more than one task at a time. Generally, the simultaneous performance of more than one automatised task (like driving a car) is easier to handle than the simultaneous performance of more than one controlled task that requires cognitive or cortical input (like placing names in alphabetic order while having to remember the names at the same time).
Sternberg focuses mainly on the mechanisms of attention rather than its possible neurological foundations. This implies that he considers the aspects of attention and its mechanisms on a higher cerebral (cognitive) level of operations, without considering possible involvement of lower brain levels or functions for support. Sternberg’s theory has been applied in many measuring instruments of attention.
Many of these instruments are computer-based continuous performance tests such as the Integrated Visual and Auditory Test (IVA). Other tests such as the Cognitive Control Battery are also based on his theory. Since Sternberg’s model is a well-known model, these two tests were included in the test battery applied in this study. In addition, the aspects included in his model are quantitatively testable, as there are certain outcomes to observe with every aspect.
Table of Contents
Chapter 1 General Orientation
2. Research Questions
3. Aim of Research
5. Research Methodology
5.1 Literature Study
5.2 Quantitative Research
5.3 Qualitative Research
6. Thesis Outline
Chapter 2 Traditional Conceptualisation And Treatment Of Attentional Difficulties And Heightened Motor Activity
2. The History of AD/HD
3. Current Clinical Diagnostic Criteria
3.1 International Classification of Disorders (ICD-10)
3.2 Diagnostic and Statistical Manual of Mental Disorders
4. Prevalence of AD/HD
4.3 Familial Patterns
5. Recording and Diagnosing Procedures
6. Associated Features and Co-Morbid Disorders
6.1 AD/HD and Behavioural Problems
6.2 AD/HD and Language Disorders
6.3 AD/HD and Learning Disabilities
6.4 AD/HD and Social Difficulties
7. Possible Causes of AD/HD
7.1 Biology and Environment
7.3 The Brain
7.4 Other General Causes
8. Developmental Course of AD/HD
8.1 Early Symptoms
8.2 Adolescents and Adulthood
9. Traditional Treatment
9.2 Behavioural Modification
9.3 Cognitive-Behaviour Therapy
9.4 Feingold Diet
Chapter 3 Theoretical Conceptualisation of Attention and Motor Activity
2. Historical Background
3 General Conceptualisation of Attention
3.2 Defining Attention
3.3 Models of Attention and Concentration
3.4 Differential Perspectives on Attention
3.5 Attention in Conclusion
4. General Conceptualisation of Movement
4.2 The Importance of Movement
4.3 Historical Background
4.5 A Model of Movement
4.6 Differential Perspective on Movement and Motor Control
Chapter 4 An Ecosystemic Conceptualisation of Attentional Difficulties and Heightened Motor Activity
2. A NEW Conceptual Framework: An Ecosystemic Approach
2.2 Physiological Stress
2.3 Psychophysiology of Stress
2.4 Information Processing / Functional Organisation
3. Neurodevelopmental Delay
4. Underlying Neurological (Sensory-Motor) Subsystems
4.1 Tactile System
4.2 Olfactory System
4.3 Gustatory System
4.4 Vestibular System
4.5 Kinaesthetic System
4.6 Muscle Tone System
4.7 Proprioceptive System
4.8 Oral Motor System
4.9 Visual System
4.10 Auditory System
5 Integration of the Basic Neurological Subsystems
6. Disintegration / Disorganisation
6.1 Information Processing System
6.2 Physiological Stress
6.3 Attentional Priorities
7 Internal and External Biochemical Ecosystems
7.2 Environmental Pollutants
7.3 Deficiencies of Essential Nutrients
7.5 Genetic Deficiency of Immune System
7.6 General Impaired Immune System
7.7 Recurrent Infections
7.8 Dysbiosis – Candida
7.9 Candida Immune Toxins, Gliotoxin
7.10 Leaky Gut
Chapter 5 Intervention Design
2. Ecosystemic Model
2.1 Sound Therapy
2.2 Neurodevelopmental Protocol
Chapter 6 Research Methodology
2 Research Design
3 Experimental Research
3.1 True Experiments
3.2 Quasi-Experimental Design
4 Data Collection
4.1 The Sample Population
4.2 The Measurement Instruments
4.4 HANDLE Screening
4.5 Sound Therapy
4.6 Integrated Visual And Auditory Continuous Performance Test (IVA)
4.7 EEG Assessment
4.8 Academic Assessment
4.10 Cognitive Control Battery (CCB)
5. The Intervention And Collection Of The Pre- And Posttest Results
5.1 Procedure Followed
6. Analysis of the Results
6.1 Descriptive Research
6.2 Inferential Statistics
7 Parametric vs Nonparametric Tests
7.1 The Wilcoxon Signed Ranks
7.2 Mann-Whitney U Test
7.3 Spearman Correlation Analysis
8. Statistical Computer Package
Chapter 7 Research Results
2. Description of the Sample
2.1 Demographic Description
2.2 Family Structure
2.3 Historical Background
2.4 Developmental Background
2.5 Intellectual Components
2.6 General Observation
2.7 Symptoms and Previous Diagnosis
2.8 Biochemical Aspects
3. Research Results
3.1 Analysis Approach
Chapter 8 Conclusion and Recommendations
2. Outline of Thesis
3. Research Results
3.2 Motor Activity
3.3 Academic Performance
4.1 Deficits in Study
5. Final Conclusion
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