Dyspraxia and its Management (Psychology Revivals)

Nick Miller

• Publisher: Psychology Press
• Year: 2015
• ISBN:
  9781317503507
• Edition: 1
• Topic: Psychology
• Subtopic: Neuropsychology
• Index: Psychology

Dyspraxia is a disorder of voluntary, purposeful, learned movement and is one of the most common sequelae of stroke, head-injury, neoplasm and abnormal ageing. It is also a major complicating factor in the assessment and treatment of acquired language, visual-spatial and other movement disorders. Dyspraxics are found not only in specialist neurological units, but also in rehabilitation centres, general medical and surgical wards, geriatric units and in the community. Despite this there was little systematic discussion of dyspraxia in major texts on stroke, head injury, rehabilitation or movement disorders at the time. Originally published in 1986, one aim of this book was to correct the imbalance in the attention paid to the disorder.

The emphasis of the book is practical, dealing with the recognition and assessment of dyspraxic dysfunction, and guidelines and issues in its remediation. Theoretical issues are covered in relation to their bearing on clinical management. It was the standard textbook on the topic for many years and directly relevant at the time to clinicians in the fields of clinical psychology, occupational therapy and physiotherapy, speech therapy, neurology and geriatrics.

1 Introduction

As tor the flight of a bullet, or a shell or bomb fragment, that rips open a man's skull, splitting and burning the tissues of his brain, crippling his memory, sight, hearing, awareness — these days people don't find anything extraordinary in that. But if it's not extraordinary, why am I iil? . . . It's depressing having to start all over and make sense out of a world you've lost because of injury and illness, to get these hits and pieces to add up to a coherent whole.

L. Zasetsky (Luria, 1972, p. 18)

This book is about impairment of movement control which cannot be explained on the basis of disruptions to afferent and/or efferent sensorimotor systems, pour or absent comprehension of the task in hand, intellectual deficit, inadequate attention or poor co-operation. It is about the person who, despite a full range of limb movements, is nevertheless unable to carry out, under all or certain circumstances, actions which they previously were able to execute; or the individual who displays degrees and types of movement dysfunction beyond what would be expected on the basis of recognisable motor, sensory, language, intellectual or interactional deficits. Both acquired and developmental forms have been described. It is not a rare sequel of brain damage.

Dyspraxia occurred in 50 per cent of unpreselected left brain-damaged patients reviewed by De Renzi. Motti and Nichelli (1980). De Ajuriaguerra, Hécaen and Angelergues (1960) found constructional dyspraxia in over 60 per cent of their right brain-damaged group. De Renzi. Pieczuro and Vignolo (1966) found 80 per cent of dysphasics to be also dyspraxic.

Despite this, a perusal of the major medical and clinical textbooks, even specialist ones on neurology, movement disorders, strokes and head injury, will probably be rewarded with only a cursory and distorted — possibly even inaccurate — mention of dyspraxia. Sometimes there may be a few pages on the subject. Discussions beyond that are very rare.

Benson (1979, p. 172) notes that dyspraxia is one of the most consistently misused terms in medical literature' Nursing textbooks hardly ever mention the disorder; paramedical works on physiotherapy, occupational therapy, speech pathology and rehabilitation in general, barely acknowledge the existence of dyspraxia, apart from perhaps one particular manifestation closely related to the work of the discipline concerned. Seldom is there an accompanying discussion of the place of that dyspraxia within the overall framework of dyspraxias and movement disorders. Some clinical neuropsychology volumes offer greater detail but, in spite of the clinical label, might be too theoretically orientated for most clinicians. Many helpful articles exist in the specialist journals, but these are scattered.

One of the aims of this book is to draw together these disparate strands under one cover and go some way towards rectifying the imbalance in the attention paid to dyspraxia, especially in respect of the front-line clinical and rehabilitational problems posed by the disorder.

Why should dyspraxia have been so neglected and misunderstood clinically? It is not because dyspraxics turn up only in elite, highly equipped and specialist centres, which one might be led to believe from much of the literature. Dyspraxics are not found only in neurology and neurosurgical units, but in general medical and surgical wards, geriatric units, outpatient clinics, nursing homes and in community practices.

Neither is it because the disorder is never a severely handicapping condition. It might not be an acute, life-threatening state, but for many people it represents the main hurdle back to an independent and fulfilling life after brain injury.

Dyspraxia is easy to overlook. Its symptoms can be passed over easily and misguidedly as resulting from other more obvious difficulties, such as hemiplegia, use of a non-preferred hand, visual field defects, dysphasia or suspected dementia. Some dyspraxics have an associated anosognosia and so they do not report difficulties; they may even deny having any problems at all.

But worse than simply missing dyspraxic symptoms is that their non-appreciation and non-recognition easily leads to misdiagnoses and consequent mismanagement of the patient. It has been known for some dyspraxics to have been falsely labelled as being confused, demented, mentally retarded, malingerers and as psychiatric cases. The dire effect this can have on an already puzzled and depressed person is obvious.

At best, such people would be left in their frustration with the explanation that it is just 'part of the general upset to the system', or 'there is bound to be a bit of clumsiness using a hand you're not used to', or, 'none of us is getting any younger, and we all get mixed up sometimes'. Worse, they might be treated as simpletons, consigned wrongly to continuing care, put on needless drug regimes for their alleged psychiatric state and denied proper help so that they never regain their rightful place in society.

Dyspraxia is easy to be missed where assessment favours a meterreading approach. It will not show up in cerebrospinal fluid analyses, muscle biopsies or routine central nervous system (CNS) observations. Neither, by its very definition (see below), will it be disclosed by examination of reflexes, muscle power and tone, primary sensation or cranial nerve function.

Dyspraxia will usually only be recognised through informed observation or by administering specific assessments. These tend not to be routinely and systematically carried out. Furthermore, in identifying, describing and 'quantifying' the difference between normal and abnormal movement patterns in general, and dyspraxia in particular, the examiner does not have available the same highly codified parameters of measurement as, for example, in the quantifications of trace elements, respiratory function or, more comparably, descriptions of language and communication applied in examining for dysphasia. Again, it is hoped that this book will go some way towards providing enlightenment in this field.

The main weight of the book's discussion will be towards practical aspects, and for this reason theoretical matters are kept to a minimum. This is not to relegate theory of dyspraxia to a subsidiary level. In the search for causes, neurophysiological correlates of the behavioural manifestations and hence a clinically and rehabilitationally useful classification and explanation, there still remain many questions of theory that are disputed or undiscovered. Where controversy exists these are mentioned, as are some of the more central theoretical considerations. References are inserted at the relevant junctures for those wishing to pursue matters of theory.

Two matters prerequisite to the detailed discussion of the dyspraxias, and which closely link theory and practice, are their definition and classification.

Defining Dyspraxia

Classically, dyspraxia is defined as a disturbance in the programming and execution of learned, volitional, purposeful movement, in the presence of normal reflexes, power, tone, co-ordination and sensation, and in the absence of visual, auditory, language, attentional and intellectual disturbances. Where there is dysfunction in any of these areas, they are insufficient to account for either the degree or nature of the errors found. With some modifications, explained in the main chapters, this is the view adopted in this book.

The literature speaks of both apraxia and dyspraxia. Strictly speaking, apraxia denotes the complete absence of conscious, purposeful movement, whereas dyspraxia means some degree of malfunction between complete absence and normal movement. Unless specifically stated the two words are used in this book interchangeably, although dyspraxia is preferred as the discussion is about disrupted rather than absent movement. The corresponding words for normal action and intact intentional movement are praxis and eupraxis.

The above definition has several implications that aid the understanding, assessment and treatment of dyspraxia, and which are now expanded.

A Disorder of the CNS

As such, dyspraxia is contrasted with peripheral neuropathies and myopathies, that is, disorders involving the lower motor neuron, the neuromuscular junction and muscle function. It also contrasts with orthopaedic movement difficulties. While this may not pose problems of differential diagnosis in adults, the picture may be more clouded in the infant or child.

A Higher Cortical Dysfunction

The classical view of dyspraxia is of a disorder of the higher cortical mental processes involved in the planning and execution of actions. While this is essentially true, some extension is necessary in the light of recent findings.

Patients have been described with circumscribed subcortical lesions (usually thalamic or striatal — see Chapters 2, 3, 4 and 6) resulting in dyspraxia. Also, some dyspraxias derive not from damage to specific cortical areas, but to subcortical connecting fibres. Further, there are disorders linked with subcortical dysfunctions that are close in nature to dyspraxia (see in particular Chapter 7).

As a higher cortical movement disorder, dyspraxia is distinguished from subcortical movement disorders, such as the disco-ordination of ataxia, the absence or slowness of movement in akinesia and bradykinesia, abnormal tone and postural reflexes, and abnormal vestibular functioning.

As a higher cortical dysfunction, the disorder in dyspraxia lies (in cognitive psychological terms) in the disruption to underlying processes. The disorder does not lie in individual behaviours. Thus, while in empirical terms it might be feasible to speak of the 'dyspraxia of pouring a cup of tea' or 'dyspraxia of waving goodbye' and, as some people do, 'dressing dyspraxia' (see Chapter 6), it is presumed here that these are behavioural manifestations of a more general underlying disability.

A Motor Disorder

As a disorder of motor planning and control, dyspraxia is separate from disruptions to action performance of a perceptual, afferent origin. Thus, in pure dyspraxia it should be demonstrated that there is normal tactile, kinaesthetic and proprioceptive input and unimpaired visual acuity.

Disorders of visual perception can feature in the differential diagnosis, as can factors such as hemispatial neglect, disorders of spatial exploration and disorders of orientation to corporeal and extra-corporeal space generally. A person who is unaware of the whereabouts of their body parts will be unable to locate or move them normally to command. In their attempts at purposeful movement, they will show corresponding disorganisation. A person with visual agnosia will not be able to locate objects to command, nor demonstrate their use. People with disorientation in space will have difficulty in copying geometrical figures and ordering objects and their component parts.

The patient with hemi-inattention will show difficulty with dressing, reading and writing, and will trip up or knock things over. The individual who has impaired haptics will not know if their glasses are on straight, if their teeth are in properly or if their bra is fastened correctly. All these behaviours can be caused by dyspraxia also, so the importance of accurate differential diagnosis is stressed to ensure the right intervention is implemented.

There is no afferent or perceptual dysfunction in pure forms of dyspraxia. However, the co-occurrence of dyspraxia with primary sensory and perceptual dysfunction is common. This renders more complicated decisions in differential diagnosis since there is more to it than simply establishing whether or not the disorder is only perceptual or only motor. The question is more likely to centre on what proportion these aspects of dysfunction are contributing to the person's disability.

Afferent and perceptual functions are extremely close to praxic functioning in that praxis is acquired largely through sensory channels, and ongoing activity takes place in a visual-spatial and tactile-kinaesthetic world that requires constant monitoring and feedback for adjustment of motor planning. This interdependence of sensory and motor components in acquisition and control of actions has been expressed by many in the use of alternate labels, such as apractognosia or sensory-motor dysfunction.

A Disorder of Voluntary Purposeful Action

The contrast here is with automatic, reflexive, random, non-purposive movement. This constitutes a main reason why dyspraxia is not recognised unless specifically sought by watching and asking the person to perform voluntary purposeful acts. It also indicates a criterion for confirming dyspraxia, that is, that a movement not performed at one time be correctly carried out in another instance.

The person might be unable to smile, frown or laugh to command, and yet when observed in spontaneous situations they demonstrate normal facial expression. They might be unable to show how to scratch their head or touch their nose, and yet are seen to do so 'subconsciously' while watching TV or eating dinner. When asked to name what they are drinking, they may struggle to say the word tea without distortion of the sounds, and yet were heard to say it clearly when casually asked minutes earlier whether they wanted tea or coffee.

Further, they may perform each of the following normally — blinking to menace, turning the head to a sudden noise, staring around aimlessly while in thought — and yet none of them is possible under conscious control to command. Similarly, overlearned activities done without conscious consideration may be executed satisfactorily, but not when requested out of their normal context, or when only part acts are required. For instance, the smoker can strike a match while lighting up, but cannot demonstrate how to strike a match on its own, or light the gas instead of a cigarette. This feature of dyspraxia is also one that can lead to misdiagnosis of dysphasia, confusion, obstinacy, psychiatric disorder or dementia if the characteristic behaviours of dyspraxia are not recognised.

A Disorder with Specific Error Types

Dyspraxia is not diagnosed simply by exclusion of perceptual, language, subcortical motor or intellectual disorders. There are also errors of inclusion characteristic of disordered praxis. The derailments to the programming and execution of actions typical of the separate dyspraxias are discussed in Chapters 2 to 7.

Classification of the Dyspraxias

Dyspraxia is not a single, invariant pattern of breakdown of movement, any more than dysphasia labels one variety of language disorder, or agnosia or dysgnosia label one form of perceptual deficit. Dyspraxia is a general term for several qualitatively different forms of disruption. Signoret and North (1979) listed 31 types of alleged dyspraxia. Several more could be added and still not have exhausted the reports in the literature. Many taxonomies have been attempted, and variations stem from several sources.

As with any CNS dysfunction, description can take place on several different levels. Descriptions at different levels do not have to be mutually exclusive, though much argument has been generated in the past by workers confusing, for example, physical with psychological descriptions. Dyspraxia...