Textbook of Clinical Neurology

It took some time for our awareness of the nervous system to evolve. It was only after the Middle Ages that the current concepts accepted in regular Western medicine were developed. Important foundations for neurological theory were laid down in the 19th century. These were corroborated using scientific techniques in the 20th and 21st centuries, and many of these methods have become normal features of clinical practice. The substantial expansion of knowledge and understanding has given rise to more and more specialist fields of neurology.

A diagnosis and treatment plan is drawn up following history-taking and clinical examination at the bedside or in the consulting room. These elements of every consultation are vital to good practice and save a good deal of time, money, problems and uncertainty, provided they are used properly. Each element of history-taking, clinical examination and diagnostic testing has a particular diagnostic value, changing the prior probability of a diagnosis into a posterior probability. If the prior probability is low it will often be decided not to collect further information. For example, we do not ask a patient presenting with knee problems whether they also happen to have a headache; we do not carry out a digital rectal examination on a patient with epilepsy for no reason; and if a patient has had non-radiating back pain for many years with no neurological symptoms or loss of function it is better not to request an MRI of the lumbar spine. This all changes, of course, if diagnosing the condition could have major consequences for the patient.

The nervous system can be divided into two parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS is a hierarchical structure, with higher centres modulating lower ones. The PNS originates in the motor anterior horn of the spinal cord and terminates in the dorsal ganglion, near the spinal cord. At rest, nerves and muscles are in electrical equilibrium. When they are stimulated, action potentials develop: these follow particular paths and produce an effect remotely through nerve-to-nerve and nerve-to-muscle communication, a process that is mediated chemically by transmitters. In pathological situations nerves or muscles fail to respond when stimulated. Electromyography provides a lot of information by measuring nerve conduction velocity or abnormal muscle action. It is carried out on patients with PNS disorders. An electroencephalogram (EEG) measures brain activity. The indications for EEG are mainly epilepsy, sleep disorders and coma. To enable readers to understand the opportunities afforded by supplementary tests in the case of neurological disorders this chapter gives a brief recapitulation of neuroanatomy and neurophysiology. A broad outline of anatomy is given in sect. 3.1, and 3.2 gives information on imaging. sect. 3.3, 3.4 and 3.5 recapitulate the physiology of nerves, muscles and motor units respectively, which is required for the explanation of electromyography in sect. 3.6. The measurement of signals in and from the central nervous system is explained in sect. 3.7, and 3.8 discusses other laboratory techniques.

Skeletal musculature is controlled by the peripheral motor neuron in the anterior horn of the spinal cord. This motor neuron acts within a reflex arc steered by sensory information from the peripheral parts of the body. The spinal reflex is modulated by higher parts of the central nervous system in order to damp the motor reaction. In the case of failing central regulation, reflexes become exaggerated and spasticity occurs. Sensory information can be divided into protopathic and epicritic sensibility. These two modalities are processed in different parts of the nervous system. There is a somatotopy for both sensory and motor functions in the central nervous system. As different systems follow different paths, it is possible to make a topical diagnosis by combining the patient’s signs and symptoms. History-taking and technically correct physical examination are therefore crucial; time needs to be devoted to these to enable a targeted investigation to be carried out. The first part of this chapter explains the physiology of sensation and reflexes and discusses the central control of strength (sect. 4.1). We then describe the examination of motor and sensory functions, with various do’s and don’ts (sect. 4.2). Central hemiplegia is common, due to central nervous system dysfunction, especially after a stroke: this is therefore dealt with separately (sect. 4.3). Not every dysfunction displayed will be indicative of actual loss of neurological function; there may be a functional neurological disorder, which needs to be recognized (sect. 4.4).

Motor control is dependent on sensory information and internal planning. There is teamwork between sensory cortical areas, basal nuclei and the cerebellum. In the case of basal ganglia dysfunction, movements are restricted, and in the case of cerebellar problems they are too large. This can be seen by observing body movements: especially gait and eye movement and speech may be dysarthric. In the case of unilateral disturbances, the contralateral basal ganglia or the ipsilateral cerebellum may be involved. It is fairly easy to identify the pyramidal tract, the basal ganglia, the cerebellum or deep sensation as the cause of a movement disorder. Functional neurological problems frequently present as a disorder of movement. The first section describes how movement is initiated in a process of constant feedback and feedforward with existing motor programmes and sensory information (sect. 5.1). The testing of motor functions as part of a full neurological examination is described in the central section of this chapter (sect. 5.2). Lastly, we discuss posture and gait pattern (sect. 5.3).

The brainstem is the portal between the brain and the spinal cord, through which signals pass in both directions. The stem also acts as the ‘spinal cord’ for the cranial senses and muscles. Various biogenic amines are produced in the stem, which regulate mood, vigilance, attention and initiative. Of the twelve cranial nerves, ten lead to or emanate from the brainstem. Unlike the spinal cord nuclei, they are usually controlled by both cortex hemispheres. The brainstem performs various vital and autonomic motor system functions. Failure of the brainstem gives rise to a life-threatening condition. An EMV score provides an indication of brainstem function. Discrete failure can be associated with a wide variety of syndromes, in the context of which the problem can be localized on the basis of the combined clinical symptoms. The brainstem anatomy is described in the first section (sect. 6.1). This is followed by a description of the cranial nerves, grouped by function (sect. 6.2). Ample attention is paid to the supranuclear, nuclear/internuclear and infranuclear eye movements (sect. 6.2.3). The examination of all twelve cranial nerves is described systematically and in the physiological context in sect. 6.3. As coma is generally accompanied by loss of brainstem functions, and symptoms of cranial nerve dysfunction are important in the diagnosis of coma, this chapter also describes the coma examination and the Glasgow Coma Scale, also referred to as the ‘EMV’ (eye/motor/verbal) score (sect. 6.4). Many cerebral disorders that cause coma jeopardize respiration, as discussed in sect. 6.5. Analogous to supranuclear spinal cord disorders, there are supranuclear brainstem disorders, which are referred to as ‘pseudobulbar’. In contrast there are bulbar disorders, the subject of the penultimate section (sect. 6.6). Lastly, some brainstem syndromes are described, mainly because they give a good impression of the symptoms of brainstem dysfunction (sect. 6.7). Disorders of the cranial nerves are described in Chap. 16. Chapter 20 looks at coma in a clinical setting.

The autonomic nervous system originates in the hypothalamus. It has two parts: a sympathetic system, with neurons in the lateral horns of the spinal cord and the prevertebral nuclei, and a parasympathetic system, with nuclei in the medulla oblongata and the conus of the spinal cord. The final neurons of the parasympathetic system are located close to the organs they serve, in contrast to other peripheral neurons, whose cell bodies are located in or close to the spinal cord. In each organ of the body, there is interaction between the two parts of the autonomic nervous system. This chapter considers in turn the hypothalamus, the pituitary gland, cardiovascular regulation, pupillomotor control, and control of the bladder and bowels.

The visual system runs from the eye to the occipital cortex and from there back to the cortical regions, which handle the functional (parietal) and emotional (temporal) processing of visual information. The system is strongly lateralized: external events on the right are processed in the left cerebrum and vice versa. A disorder can normally be localized within the visual system by testing the visual fields. After being registered in the occipital cortex, visual signals are analysed and synthetized to form an identifiable concept. The main disorders of the central visual functions are visual hallucinations and delusion, palinopsia, neglect, loss van spatial awareness, inability to name things or read, and inability to recognize functional objects of faces.

The cerebrospinal fluid system (CSF) lies at the centre of the brain and extends throughout the nervous system, between the two innermost cerebral meninges. CSF is produced in the ventricles and drains from the top of the convexity in the dural venous sinuses. The function of the CSF is not entirely clear. However, it is known at least to perform a mechanical function. Analysis of the CSF for sugar, proteins, immunoglobulins, cells and other substances provides a basis for accurate diagnosis, since various conditions are associated with distinct CSF characteristics. Disorders of the CSF system can lead to hydrocephalus, intracranial hypertension and intracranial hypotension (all of which can be treated with reasonable efficacy).

The cerebrum is supplied both by the carotid arteries and the vertebral arteries (which unite to form the basilar artery). These three blood vessels are connected by a properly developed circle of Willis, so that if one fails the others can take over to a degree. Basilar artery occlusion leads inevitably to major neurological symptoms and signs, however, since the brainstem is deprived of oxygenated blood. Regulation of the cerebral vascular system is autonomous of the rest of the body, so that a fall in blood pressure does not immediately affect the cerebrum. If cerebral perfusion is impaired, infarction can occur. That gives rise to various syndromes, depending on which region is affected. Blood vessel abnormalities in the form of aneurysms, arteriovenous malformations, dissection and a number of less common problems lead to neurological conditions and potentially to serious disability. Diagnosis is based on CT, MRI, intra-arterial contrast angiography and/or duplex scanning.

Diseases of the muscles and the neuromuscular junction have a common symptom, namely loss of strength. Atrophy and cramps are other features. Many muscular diseases have a genetic cause and are often difficult to treat, but this is why it is very important to recognize acquired diseases, as a good deal can usually be done about them therapeutically. When classifying muscular diseases a distinction needs to be made between proximal and distal myopathies, and between diseases with and without myotonia. Myasthenia is a special case: unlike many other disorders discussed in this chapter, it often causes diplopia, and the severity of the symptoms fluctuates. Myasthenias are usually autoimmune diseases and as such respond well to treatment, but incorrect treatment can cause life-threatening situations. In cases of muscular disease, consideration needs to be given to cardiopulmonary involvement, care should be taken with anaesthesia, and good genetic advice must be given.

Disorders of the peripheral nerves and nerve roots are usually acquired, unlike muscular diseases, which are often hereditary. Disorders of the peripheral motor neuron can be classified based on anatomy, loss of function and pathophysiology. Acquired dysfunction can be caused by metabolic or vascular disorders, compression and inflammation. Anterior horn cell (motor neuron) disorders are purely motor syndromes. Amyotrophic lateral sclerosis (ALS) is the most familiar cause. Polyneuropathy is a common feature of a systemic disease such as diabetes, but can also be caused by medication (chemotherapy in particular). Inflammatory neuropathies cause mainly symmetrical loss of strength; they have an acute (Guillain-Barré syndrome) or chronic course (chronic inflammatory demyelinating polyneuropathy, CIDP) and often respond well to treatment. Local nerve problems cause asymmetrical dysfunction, and sometimes pain. Familiar causes of mononeuropathy are carpal tunnel syndrome and paresis of the foot extensors due to pressure on the peroneal nerve. More extensive local dysfunction can be caused by plexopathy.

Pain can be classified into nociceptive (tissue damage) and neuropathic (nerve damage, neurogenic). Nerve pain is by definition neuropathic pain, but it may be accompanied by nociceptive pain, depending on the cause, the best example being a herniated intervertebral disc resulting in a radicular syndrome. Nerve pain can also be due to inflammation or trauma.

The causes of myelopathy are various. The damage to the spinal cord may be complete (as in the case of complete spinal cord injury) but it is more often incomplete (as in the case of an incomplete traumatic spinal cord injury and most types of myelopathy due to non-traumatic causes). There are some ‘classic’ spinal cord syndromes, but they can present atypically. In practice, information from the history-taking combined with examination of the main tract systems enables the localization of the damage to be determined and a differential diagnosis to be formulated. A basic knowledge of the anatomy (the siting of tract systems, segmental levels) of the spinal cord (Chap. 4) and an understanding of central and peripheral weakness and the patterns of various sensory modalities are needed to understand neurological symptoms at spinal cord level properly. Given this knowledge, it is generally not difficult to determine the level and spread of the spinal cord problem. This chapter begins with a brief introduction including a description of a complete spinal cord injury by way of illustration (sect. 15.1). A brief section on diagnostic imaging (sect. 15.2) is followed by three sections on traumatic structural lesions (sect. 15.3), non-traumatic structural lesions (sect. 15.5) and non-structural lesions (sect. 15.6). In between (sect. 15.4) we deal with the diagnostic options for non-traumatic disorders. Demyelinating disorders follow in Chap. 25, and hereditary syndromes in Chap. 26. Spina bifida is discussed in Chap. 29 (sect. 29.3.2).

Damage to the cranial nerves results in sensory function loss and/or the loss of facial motor control: hearing and sight may be lost, double vision or dizziness may develop, swallowing and speech may be more difficult, the face may become lopsided, or hypersensitive or numb. Cranial nerve problems can usually be traced and resolved. That is the case, for example, with viral infections, compression due to intracranial hypertension, medication poisoning, autoimmune disorders and the influence of meningitis. The theory underlying this chapter is discussed in Chap. 6 and 9. Here we discuss disorders of cranial nerves I-XII sequentially, including neuro-ophthalmology and neuro-otology.

Cerebral infarctions and cerebral haemorrhages are cerebrovascular disorders. They are a major cause of mortality and disability. Imaging is required to make the correct diagnosis. Cerebral infarctions are caused mainly by thromboembolisms, which can develop at the site of an atherosclerotic stenosis; there are also cardiac sources of embolism and other causes, though the latter are rare. A TIA is in fact an impending cerebral infarction and needs to be diagnosed quickly. The possibility of thrombolysis and mechanical thrombectomy during the acute phase means that a cerebral infarction is a medical emergency. Hypertension, amyloid angiopathy and vascular malformations can cause intracranial bleeding. Non-traumatic subarachnoid haemorrhages are usually caused by a ruptured aneurysm. Cerebral venous sinus thrombosis is a much rarer cause of cerebral infarction or haemorrhage than arterial cerebral infarction. The treatment of patients with cerebrovascular disorders at a stroke unit is multidisciplinary. If residual symptoms are present after a cerebral infarction or cerebral haemorrhage the success of rehabilitation is affected by cognition and mood. This chapter builds on our basic understanding of the cerebrovascular system, which is discussed in Chap. 11. A general introduction (sect. 17.1–17.3) is followed by a description of ischaemic accidents (sect. 17.4–17.5). We then look at haemorrhages: intracerebral (sect. 17.6) and subarachnoid (sect. 17.7). Subdural and epidural haematomas are dealt with in a different chapter (sect. 21.6). A few other specific areas are discussed at the end of this chapter (sect. 17.8–17.10). We return to neurovascular abnormalities in the chapters on movement disorders (Chap. 27), dementia (Chap. 18) and the final chapter on neurological complications (Chap. 30).

There are many types of seizure, and by no means every seizure is caused by epilepsy. Seizures need to be classified as precisely as possible, as the classification affects the likelihood of a symptomatic or hereditary cause and the treatment and prognosis. Treatment for epilepsy needs to be tailored to the patient. In addition to drug treatment – and sometimes surgery – it is important to consider lifestyle and life stage (contraception, pregnancy, etc.). The first part of this chapter deals with seizures in general and the differential diagnosis required (sect. 18.1), followed by a discussion of epilepsy (sect. 18.2.1), causes (sect. 18.2.2) and syndromes (sect. 18.2.3). A separate section is devoted to childhood epilepsy (sect. 18.2.4), and this part ends with a discussion of the treatment and monitoring of epilepsy (sect. 18.2.5). The last part of the chapter deals with non-epileptic seizures (sect. 18.3). This chapter also links up with the next chapter, on sleep (Chap. 19), and the chapters on movement disorders (Chap. 27) and dementia (Chap. 28).

Sufficient good-quality sleep is one of the mainstays of a healthy lifestyle. What ‘good sleep’ means, however, is not an easy question to answer, for one thing because we do not know what the precise function of sleep is. The assumption is that it is involved in maintaining neuronal networks, including strengthening and consolidating memory, and also in gene expression. Sleep, then, is not just a period of rest but also an active process that depends on sleep pressure (Process S), the biological clock (Process C), age, any underlying illnesses and use of substances and/or medication. Process S is the homeostatic sleep drive: the longer we do not sleep, the stronger that pressure for sleep becomes.Our sleep pattern changes during life. Polysomnography is providing a growing understanding of what happens during sleep and what can go wrong. There are four types of sleep disorder: hypersomnia, insomnia, sleep-related behaviour and movement disorders, and lastly delayed sleep phase syndrome. Many patients with neurological conditions suffer from sleep disorders, which may precede the illness itself.This chapter begins by discussing the physiology of sleep (sect. 19.1). We then explain how sleep diagnosis is carried out (sect. 19.2). The third section deals with the aforementioned four types of sleep disorder (sect. 19.3), and the chapter closes with a brief overview of neurological disorders in which sleep disorders play an important role (sect. 19.4).

Full consciousness is characterized by wakefulness, focused attention and normal cognitive function. A coma patient by definition has closed eyes, does not respond to commands and does not talk, an urgent situation that calls for the cause to be found as soon as possible. Coma can be caused by damage to brain tissue, hypoxia, metabolic dysregulation or intoxication. It can also be due to a brain herniation syndrome. The prognosis for postanoxic coma depends on how long the patient has been unconscious. If there is no obvious cause of the coma, the possibility of non-convulsive status epilepticus should always be considered. Delirium patients have impaired attention to and perception of their surroundings. Frontal injuries can produce a state of ‘lack of will’ (abulia). Coma can be followed by vegetative state or unresponsive wakefulness syndrome, in which the patient has no awareness of their surroundings. Brain death is a diagnosis that can only be made if strict conditions are met; this diagnosis is required for organ donation. The brainstem plays an important role in consciousness and impairments of consciousness: its functions and testing are discussed in Chap. 6 (sect. 6.1, 6.4 and 6.5). Chapter 18 deals with attacks of impaired consciousness and Chap. 19 with physiological changes in consciousness. This chapter looks at pathological impairments of consciousness, which can affect level and/or content (sect. 20.1). Rapid action to decide on a good strategy is important (sect. 20.2). In a case of cerebral herniation (sect. 20.3) the course of the condition follows a fixed pattern, depending on the type of herniation. Disturbances of the internal environment can involve metabolic dysregulation (sect. 20.4.1), intoxication (sect. 20.4.2) and status following anoxia (sect. 20.4.3). Coma can in fact be caused by non-convulsive status epilepticus (sect. 20.5). The next section (sect. 20.6) considers consciousness that is altered but not lowered. This chapter concludes with vegetative state following coma (sect. 20.7) and total loss of brain/brainstem function, i.e. brain death (sect. 20.8). Chapter 21 deals with structural coma again. The final chapter of the book (Chap. 30) discusses the neurological effects of internal medicine disorders systematically, again looking at coma.

Every year Accident and Emergency departments see large numbers of patients with traumatic head injuries, some including brain injuries. These brain injuries are usually mild, and the vast majority of these patients do not develop any acute complications. It is important to provide good-quality standardized care in the acute phase, as a very small proportion of these patients develop potentially severe intracranial complications that can be fatal if not diagnosed and treated in time. A brain injury may be accompanied by damage to the neurocranium and base of the skull, which in turn can lead to cranial nerve damage, hearing loss and leakage of CSF. A minor traumatic brain injury can give rise to lasting post-traumatic symptoms that affect day-to-day life. If a patient survives a severe traumatic brain injury, the severity of the residual disability will often be determined far more by mental and cognitive than physical sequelae. Traumatic brain injury can be classified in various ways, based on clinical parameters (sect. 21.3.1), the location of the trauma damage to the skull and brain (local or diffuse, sect. 21.3.2), and progression over time (primary or secondary, sect. 21.3.3). This classification is important for diagnosis, treatment and the ultimate prognosis. The diagnosis and treatment of patients with head injury needs to be standardized to enable optimum recovery (sect. 21.1 and 21.4). The aim must be the prompt identification of neurosurgically treatable cranial and intracranial abnormalities (sect. 21.5 and 21.6) that could cause increased intracranial pressure (sect. 21.3.4), herniation (Chap. 20) and ultimately a poorer outcome or even death. The prognosis for traumatic brain injury (sect. 21.7) will depend on the severity of the injury (clinical and radiological), and there is an association with certain neurodegenerative disorders in later life (sect. 21.7.4).

Headache is a common complaint in both primary and secondary care. Careful history-taking is the most important tool for diagnosing it. Some types respond well to treatment, others are virtually intractable to standard treatments. A general discussion of headache (sect. 22.1) is followed by a detailed consideration of migraine (sect. 22.2). We then look at cranial neuralgias (sect. 22.3) and cluster headache (sect. 22.4). Temporal arteritis is somewhat beyond the scope of this chapter but it should not be missed and is therefore described briefly in sect. 22.5. Tension-type headache and migraine are the most common types (sect. 22.6). It is important to recognize medication-dependent headache (sect. 22.7). There can sometimes be a potentially serious underlying cause (symptomatic headache), especially if the pain is acute (sect. 22.8). Clinicians need to be on the lookout for red-flag symptoms (sect. 22.9).

Brain tumours can cause general symptoms (such as memory problems, lethargy) and focal symptoms (such as weakness, epilepsy). The most common primary brain tumours are low-grade and high-grade tumours that arise from glial tissue (gliomas). A second group consists of tumours originating in the cerebral meninges (meningiomas). Pituitary tissue tumours (pituitary adenomas) are less common, as are neuromas or schwannomas that arise from myelin-forming cells, usually around cranial nerves, nerve roots, or peripheral nerves. Brain metastases develop in 20 % of cancer patients. Leptomeningeal metastases are located in and around the cerebral meninges or the membranes surrounding the spinal cord. Intramedullary tumours (primary or metastases) are rare. Transverse lesions due to cancer-related spinal cord damage are caused mainly by a vertebral metastasis (or metastases) that spreads (spread) into the epidural space. Paraneoplastic neurological syndromes are rare. They often present as the first manifestation of cancer elsewhere in the body. This chapter deals with the various types of tumours that occur in, and adjacent to, the brain and spinal cord. This generally concerns tumour-related complications (sect. 23.1) and clinical symptoms (sect. 23.2). Next, we address solid tumours (sect. 23.3) and metastases (sect. 23.4 to sect. 23.6). The final part of this chapter deals with paraneoplastic symptoms and treatment complications (sect. 23.7). The various types of cancer treatment can cause complications (sect. 23.8). The final topic addressed here is the organization of neuro-oncological care (sect. 23.9). A knowledge of cerebral and spinal localization principles (Chaps. 4 to 7 and 15) and of the higher cerebral functions (Chap. 8) is essential for a proper understanding of this chapter. Brain tumours can (eventually) cause impairments of consciousness and a brain herniation syndrome (Chap. 20).

Meningitis is usually caused by a virus, in which case the prognosis is good and the treatment usually symptomatic. Bacterial meningitis is less common, but its course is far more severe. Encephalitis or meningoencephalitis also involves inflammation of the brain parenchyma. The key symptoms of all these infections are headache and fever. Both of these are non-specific symptoms and need not both be present, and by no means every patient with these symptoms will have an intracranial infection. Thus, it can be difficult to diagnose infections of the central nervous system and cerebral meninges. This is certainly the case in very young and very old patients, who generally display even fewer classic symptoms. This chapter covers various infections of the central nervous system, cerebral meninges, spinal cord, and nerves. The symptomatology depends on the degree of damage to the brain parenchyma or spinal cord. There is a particular focus on meningitis (sect. 24.1), abscess (sect. 24.2), and viral diseases (sect. 24.3).

Multiple sclerosis is a disease of the central nervous system. It is the most common cause of disability among young adults in the Western world. It is characterized by a wide variety of neurological symptoms and signs, a combination of new transient symptoms and gradually progressive loss of function over a lengthy period. There are several types of disease course. The diagnostic criteria are abnormalities that are dissociated in time and place. MRI is the most important diagnostic test. There is no causal treatment for MS as yet, although there are immunomodulatory and immunosuppressive treatments. There are also symptomatic treatments. MS needs to be distinguished from other demyelinating disorders. Following a general discussion of MS in sect. 25.2–25.4, the clinical symptoms of MS are dealt with in sect. 25.2. The diagnostic criteria are presented in sect. 25.5. MS therapy is flourishing. It is discussed in the next section (sect. 25.6), but only in outline. If a white matter (myelin) disorder is diagnosed, MS is not the only possibility (sect. 25.7). In addition, various other disorders have multiple neurological symptoms that could be consistent with MS, but these have a different autoimmune genesis. These disorders are discussed at the end of this chapter (sect. 25.8).

Spinocerebellar disorders are often neurodegenerative diseases. They constitute a large group of rare disorders characterized by various manifestations of ataxia, in some cases with selective dysfunction of other systems (e.g. the corticospinal tract). Damage to the corticospinal tract is the key symptom of some other neurodegenerative disorders, namely hereditary spastic paraplegia and primary lateral sclerosis. The ability to diagnose these various disorders has improved enormously thanks to the rapid developments in DNA testing. The treatment is currently still purely symptomatic. Rather than focusing on all manner of rare disorders, this chapter is primarily intended to spotlight developments in the field of neurodegenerative disorders, as well as the various ways in which these can be regarded from a clinical and genetic point of view. By way of an introduction, there is a general discussion of neurodegenerative disorders, which also extends to other chapters (sect. 26.1). This is followed by a classification of spinocerebellar disorders, in which both hereditary and non-hereditary forms are described (sect. 26.2). The section after that deals with the autosomal dominant, autosomal recessive, and non-hereditary forms respectively, linking clinical and genetic aspects where possible (sect. 26.3). The final topic is another neurodegenerative disorder, that mainly affects the spinal cord – hereditary spastic paraplegia (sect. 26.4).

Movement disorders are neurological disorders in which patients involuntarily move ‘too little’, as in Parkinson’s disease (PD), or on the other hand ‘too much’, as in dystonia. As explained in Chap. 4 and 5, movement is ultimately controlled by the corticospinal tract (pyramidal tract). Before a movement is performed, however, extensive preparation takes place, and the movement is constantly monitored to see if it is as intended. The cerebellum and basal nuclei play a key part in this. Cerebellar disorders were covered in the previous chapter. In this chapter we discuss the disorders that are traditionally classified as diseases of the basal nuclei. Extrapyramidal disorders are caused by abnormalities in the mesencephalon and basal ganglia. There are two forms of parkinsonism – typical (PD) and atypical. PD, the most common chronic disease of the central nervous system in individuals over the age of 50, always causes more than just motor symptoms. Clinical criteria are used to reach a diagnosis. Structural and functional imaging may be needed to distinguish the various forms of atypical parkinsonism from PD itself. There are good treatments available for Parkinson’s disease, and a multidisciplinary approach is required. Atypical parkinsonian disorders include vascular parkinsonism, drug-induced parkinsonism, multiple system atrophy, progressive supranuclear palsy and corticobasal degeneration. Parkinsonism is not the only extrapyramidal symptom, the others are tremor, chorea, ballism, myoclonus, tics, and dystonia. This chapter builds on our basic understanding of movement control, which was explained in Chap. 5. The main movement disorders are covered, with a focus on typical disorders, as characterized by parkinsonism or PD (sect. 27.1). With regard to this disorder, there is a detailed exploration of clinical features (particularly the distinction between motor and non-motor symptoms (sect. 27.1.1 and 27.1.2), current views on pathophysiology (sect. 27.1.4), reaching a diagnosis (sect. 27.1.5), and treatment options in the early and late stages (sect. 27.1.6). The much rarer atypical forms – the various Parkinson-plus syndromes – are briefly discussed in sect. 27.2. The various hyperkinetic movement disorders (tremor, dystonia, myoclonus, chorea, and tics) are dealt with in sect. 27.3. Several rules of thumb are provided, as an aid to diagnosing these disorders. The chapter concludes with a discussion of the various forms of deep brain stimulation that can be used to treat patients whose movement disorders have not responded adequately to drug treatment (sect. 27.4).

Dementia is an acquired disorder involving the deterioration of various cognitive functions with intact consciousness. Behavioural problems and emotional changes occur sooner or later in any form of dementia. The most common cause of dementia is Alzheimer’s disease (AD). Dementia can also be caused by vascular brain damage. Frontotemporal dementia is characterized mainly by changes in behaviour. Lewy body dementia (LBD) involves a combination of dementia and parkinsonism. Several atypical forms of parkinsonism (sect. 27.2) may be associated with dementia. These may precede motor symptoms and other symptoms. Creutzfeldt-Jakob disease (Creutzfeldt-Jakob disease, CJD) is a rapidly progressive, fatal disorder. Dementia can develop in the late stages of AIDS and syphilis. This chapter explores the dementia spectrum and the various disorders that can cause dementia. The latter range from common (AD; sect. 28.5) and vascular dementia (sect. 28.6) to very rare (CJD; sect. 28.10) and paralytic dementia in syphilis, which used to be common but is now very rare (sect. 28.11). Chapter 8 deals with our basic understanding of higher cerebral functions. There are also links to Chap. 27, concerning syndromes with movement disorders.

Although many neurological disorders can affect children as well as adults, many are specific to childhood, such as congenital abnormalities of the nervous system and perinatal brain damage. The severity and nature of congenital disorders depend on the cause and when it occurred. Impaired proliferation and migration of neurons can cause learning disabilities, motor problems and epilepsy. Congenital disorders due to chromosomal aberrations often cause learning disabilities. Intrauterine infections can cause severe abnormalities. Hereditary metabolic diseases can give rise to developmental disorders but may not manifest themselves until later in life. Neurocutaneous diseases are disorders involving the ectodermal structures of the nervous system and skin. Childhood ataxia can be a manifestation of very different disorders. Paediatric neurology is concerned with disorders of the central and peripheral nervous system and the muscles, in children from the prenatal period up to 16 to 18 years of age. Although not a recognized separate medical specialism in most European countries, it is an area for which additional training is required. About half of specialists dealing with paediatric neurology have a background as neurologists, the other half as paediatricians. A full understanding of neurological deficits in children requires a sound grasp of normal CNS development. Therefore, this chapter’s opening sections are essential. Many symptoms and disorders are also dealt with elsewhere in this book. These include the various forms of epilepsy (sect. 18.2.1) as well as neuromuscular and anterior horn diseases that manifest themselves in childhood (sect. 12.4 and 13.2.2). Paediatric neurology differs from ‘ordinary’ neurology in several respects. First, there are specific disorders that occur in childhood, such as congenital abnormalities of the nervous system (sect. 29.3) and brain damage due to perinatal problems (sect. 29.3.9). Other examples are various neurometabolic and neurodegenerative diseases, some of which even cause affected children to die before they reach adulthood (sect. 29.4). Secondly, every disorder develops against the background of the developing nervous system. The clinical presentation is determined by the sum of the positive effects of the maturing nervous system on the one hand and the negative effects of the disorder on the other. A good example is a perinatal cerebral infarction, which will not cause clear symptoms of hemiparesis until the child reaches one year of age. This phenomenon is known as growing into deficit. A certain degree of cerebral development is needed before any functional disorder manifests itself. Then there are disorders that occur at all ages, such as traumatic brain injury and infections, which have a different impact on the young nervous system than on that of an adult. Children are more vulnerable, but on the other hand they have greater plasticity and ability to recover. Lastly, neurological examinations in children are very different from those in adults, and each age has its own requirements. This chapter discusses some disorders specific to childhood that are fairly common (cerebral palsy or infantile encephalopathy), as well as diseases that are fairly rare (many metabolic disorders). These rare diseases are nevertheless discussed in order to provide some understanding of mechanisms that can cause neurological problems (which are often severe) at a young age. On the other hand, many neurological disorders that can affect adults can also occur in children. These are mainly discussed elsewhere in this book, stressing the paediatric neurology aspects where necessary.

Neurological disorders resulting from deregulation of the body’s internal milieu, problems with more peripheral organs, and the adverse effects of therapy are commonplace. It is important to identify the underlying ‘non-neurological’ substrate. This is essential for timely diagnosis and treatment, and to prevent additional or permanent neurological damage. This chapter is certainly not intended as study material, but rather as a reference work for neurological consultations in clinical departments or neurological outpatient clinics. As more and more therapies enter use, it is increasingly common to encounter neurological problems that are the adverse effects of therapy, or that result from an ongoing non-neurological disorder. This chapter considers the main topics.