Sophie Scott, 23^rd February 2000

Strokes tend to follow the pathways of the cerebral arteries. There are other forms of brain damage, namely head injury and dementia.

Speech and language problems can happen; depends on location of damage.

Open vs. Closed head injury.

Open: the brain or meninges are exposed

Closed: meninges are intact, although the skull may be fractured.

Historically - mainly open, due to war wound.

Modern day: mainly closed, mainly car accidents. This means that, predominantly, the patients are young males (a profile unlike most other brain problems) and that legal issues and compensation can be an issue. On the whole, those with closed head injuries have a better prognosis for recovery of communication disturbances than open head injuries.

simple cracks or fissures in skull bone, intact skin

compound cracks in skull and skin broken

comminuted damaged skull in several pieces

depressed a piece of broken skull is driven inwards, causing laceration or compression or the brain tissue.

No direct relationship between size of fracture and amount of damage; more important to understand location and extent of damage to brain tissue. depressed skull fractures are the most serious.

The skull need not be broken for the brain to be damaged, and for consciousness to be lost. In fact consciousness can be lost without underlying damage; if patients make a full neurological recovery in 1-2 hours then they are concussed. This leads to no long-term impairments.

A brain contusion (bruise) is a disturbance of the brain following an injury in which there have been multi-focal capillary haemorrhages, vascular engorgement and oedema. This is exactly the same as a bruise on your skin. Can happen under the impact, or on the opposite side of the brain from the impact (contre-coup contusion), due to the fact that the brain moves about within the skull. If, during this movement, the brainstem twists, then there can be a brainstem contusion. The symptoms depend on the location of the contusion, e.g. language disturbances, speech disorders, hemiparesis etc. Brainstem contusions cause alterations of consciousness, cranial nerve palsies and disturbances of postural tone.

If the contusion is big enough to cause a 'visible breach in the continuity of the brain' (i.e. a tearing of the surface) then this is a laceration. Mainly associated with a penetrating head wound and a severe unconsciousness.

This is a very common consequence of TBI. The adult brain is in a fixed box, filled with brain tissue, cerebro-spinal fluid and blood. Slow forming lesions (e.g. tumours) can develop sufficiently slowly that the system adjusts the pressure around it. Rapid increases, however, cause problems. One of these is that brain tissue can be displaced into another cranial compartment - this is called herniation.

a) transtentorial herniation. The tentorium cerebelli is a fold in the dura mater separating the cerebral hemispheres from the cerebellum and the brainstem. Upper brainstem passes through a hole called the tentorial hiatus. An increase in pressure above the tenotorium (e.g. due to extra or sub dural haematoma) may cause medial temporal lobe regions to be forced down this hole. This compresses the brainstem and thus consciousness deteriorates. Pressure on the 3rd cranial nerve causes pupilary dilation, first on the side of the hernia and then on the other as well. If untreated it will lead to death. Consciousness and pupils must be monitored in head injury.

b) tonsillar hernication

Occurs when the cerebellar tonsils are displaced through the foramen magnum. This compresses the medulla, leading to respiratory insufficiency or apnoea.

c) Axial herniation

Increased ICP leading to a downward shifting of the entire brainstem. No structures are compressed, but the distortion of the brain stem can lead to respiratory problems and variation in consciousness.

Result from laceration of the middle meningeal artery by bone, leading to bleeding between the skull and the dura mater. These tend to collect and enlarge rapidly, problems due to increased ICP are apparent very soon after injury. Typically the patient was knocked out, consciousness recovering quickly, then within 1-2 hours the patient becomes drowsy and has paralysis down one side of their body. Pupil dilation and loss of consciousness will follow due to herniation. Treatment involves reducing ICP with a hole in the skull over the haematoma, otherwise the patient will die as respiration etc. is lost. Aphasia is rarely seen due to the rapid onset.

Results from bleeding between the dura mater and the brain, into a space normally filled with lymph. These develop more slowly, with the same signs developing but over a longer period, the patient will often complain of a headache, and also show word finding problems. It may also trigger a fit as it develops. Again, surgical intervention is necessary.

A rupture of the blood vessels between the bottom of the brain and the pia mater. Common after a head injury and show as blood in the cerebrospinal fluid (unlike the previous 2). There may be severe headaches and neck stiffness, but there will be a spontaneous recovery.

The injury can cause damage within the brain itself - multiple small lesions in the contused region. Depending on the location, these can cause a variety of speech and language problems.

Function of the nerves can be damaged in the brain stem nuclei, or the nerves themselves. Brainstem contusions can lead to flaccid paralysis of the muscles. Fractures to the base of the skull can cause damage to the nerves themselves, esp. to the facial nerve. These can thus cause speech problems (e.g bulbar palsy). Bulbar refers to the larynx, pharynx, palate etc. and the brainstem nuclei of the nerves that control these, of the external nerves themselves, are damaged. The facial muscles can waste away and the speech can be very nasal.

6. Rhinorrhoea and Otorrhoea

After TBI, cerebrospinal fluid may lead from the nose (rhinorrhoea) or the ear (otorrhoea). The former is due to fracture of the frontal bone with tearing of the dura mater and cortex. The latter is due to injuries to the base of the brain, often also including the brainstem, so this is potentially more serious. Both can lead to risk of meningitis.

These are complications which are not terribly incapacitating but can affect lifestyle. Posttraumatic epilepsy mostly often happens after a penetrating head wound, leading to scar tissue which can be an irritating focus which triggers fits. This can happen soon after impact, esp. in children. Some form of post-traumatic vertigo is quite common, leading to unsteadiness and sickness.

The damage can be

• focal
• multi-focal
• diffuse

Generally, open head injuries (OHI) are focal, and closed head injuries (CHI) are diffuse. This latter type is more common in civilian life. Force is distributed over the whole brain (physics!) and the whole brain suffers as a result. Lacerations, contusions, and haemorrhages all can result from:

• direct trauma of impact
• acceleration of brain against the bony inside of the skull
• contra-coup trauma on opposite side to impact.

There are 3 destructive forces:

• Compression forces brain tissue together
• tension pulls it apart
• Shearing is due to rotational acceleration, as the brain is dragged across bony or ligamentous ridges within the brain.

All of this leads to diffuse neuronal damage at the time of impact. This can include:

• Severe localised demyelination
• White matter degeneration
• Nerve cell damage

White matter is especially affected by shearing and stretching of nerve fibres, particularly in the corpus collosum.

People often have a communication problem following head injury. There is controversy about the nature of these problems, especially whether the patients are aphasic or not.

Several researchers have identified 'aphasic' problems post TBI.

e.g. Heilman, Safran and Geschwind (1971) studied 13 patients with aphasia after a CHI, found 9 cases with anomic aphasia, fluent speech output , normal comprehension and repetition and verbal parahasias and poor object naming. The other 4 had fluent paraphasic speech output and poor comprehension and repetition - very like classic Wernicke's aphasia. There were no Broca's or global aphasics. Other studies found similar results. On the whole the patients were anomic, sometimes called expressive aphasia. The more severe the injury, the more severe the problem, especially over time. Prolonged coma often leads to non-specific language disturbance.

Groher (1977) studies the progression of this over time. CHI, average 17 days in a coma. Patients assessed as soon as consciousness reached, then reassessed every 30 days for 4 months.

When acute, gestural skills were worst, followed by graphic skills, followed by verbal skills. All subjects were anomic and made paraphasic errors. Reading comprehension was poor and several were dyasrthic. By the final assessment, all could make their needs known and could converse, but 9/14 used inappropriate language and had confused thought content. Writing got a bit better and reading comprehension remained poor. Graphic and gestural skills became better than verbal skills.

Several researchers have questioned the validity of aphasic classifications for this kind of brain injury. Some of the initial language problems may be due to posttraumatic amnesia, when people are confused and don't 'form' memories of this time. This has been extended to show that Short Term Memory (STM) for non verbal material correlates with linguistic abilities in such patients. Post TBI, patients may have language problems due to their being confused, with a poor STM, mistaken reasoning, inappropriate behaviour, lack of understanding of the environment and disorientation. Speech can thus be 'irrelevant' in content, while still being fluent and syntactical (Darley, 1982). Patients can confabulate, or form reduplicative para-amnesia, in addition to any language problems.

Holland (1982) described 3 ways in which TBI is different to stroke populations that underlie differences.

1. Aphasiology arose from OBI (war wounds), CHI is much more common in current times, and the type of damage produced is different. Deficits reflect this, with CHI causing diffuse brain injury, with pervasive memory and cognitive deficits.

2. As a result of this, the rehabilitation of CHI is more interdisciplinary than that of stroke.

3. There is a big demographic difference: TBI = 15-24 years old, stroke more common in middle to old age - better prognosis for TBI?

There are some similarities, esp. in anomia. However the mechanisms may be different. As well as the circumlocutions or paraphasias found in anomia of vascular origin, 'non-aphasic' naming errors are made, involving misnamings or confabulations.

There is also often a sensory deficit, with impaired auditory comprehension, and comprehension of complex material can persist for some time.

Holland felt the area where they were most different was pragmatics. If aphasia is a disorder of form, while TBI language can show a disorder of use. Thus there can be problems in orientation explanations, visual attention and utilisation of contextual cues, as well as reasoning (Milton, Prutting and Binder, 1984).

Levin et al (1981) did a follow up of recovery, based on initial severity of head injury, as assessed by the Glasgow Coma Scale and CT scans. There were 3 patterns of recovery.

1. Full language function recovered if initial injury was mild, e.g. haematoma in only one hemisphere.

2. After some mild head injury, expressive deficits can remain for at least 6 months post onset, with anomia. Generally spared diffuse cerebral damage.

3. More severe damage, with diffuse swelling and bilateral haematomas correlated with persistent expressive and receptive impairment at least one year post injury, with residual aomia, and non-verbal and verbal deficits.

Most linguistic recovery occurs within the first 6 months, especially in the first 1 month. Memory problems tend to resolve first. There is disagreement about the best way of predicting outcome. Some studies find a correlation between coma length and severity of linguistic problems, others do not.

These are common following TBI, especially dysarthira. Depending on where there is damage, there may be flaccid dysarthria, spastic dysarthria, or mixed dysarthria.

Flaccid dysarthria may result from damage to the cranial nerves in the periphery or in the brainstem nuclei (bulbar palsy)

Spastic dysarthria, associated with damage to upper motor neurones (motor cortex) (pseudo-bulbar palsy)

More extensive damage (*upper and lower motor neuroines) can cause mixed dysarthria, either mixed spastic/flaccid dysarthria or spastic/ataxic dysarthria. (Bulbar and psuedo-bulbar palsy)

This all normally accompanies a general language disturbance, though the dysarthria can persist.

The prognosis for speech and language is generally good, though like the rest of this field, it is controversial. The removal of haematomas and reduction of ICP accounts for some of the recovery in the first 1-3 weeks. Oedema can subside, blood flow to (not irreversibly damaged) regions can resume. Recovery is claimed to continue like this for up to 3 months then slows. The nature of the rest of recovery is not well understood. It is possible that there is recovery of undamaged but inactive brain tissue - temporarily stopped from functioning due to 'shock'. Longer-term recovery may be due to functional re-organisation of neural tissue, and axonal regrowth, collateral sprouting can contribute. We cannot grow whole new neurones.

The recovery from coma follows a set course.

1. Eyes open as brain stem recovers functions concerning wakefulness. Words may be uttered.

2. A possible period of 'cerebral irritation' - a lot of swearing and aggression!

3. A period of quiet confusion

4. End of post traumatic amnesia (*length of this period, rather than coma, can correlate with outcome)

5. Subtle abnormalities can now be seen, patient can return home, behaviour can still be erratic.

People can return to work, but this can be unsuccessful. They can have problems with judgement and concentration. There can be problems with complex communicative language use. In general, the main problem post TBI is one of Sustained attention - keeping engaged in a task that may not itself be intrinsically interesting (like most of work!).

A persistent impairment in intellectual function due to brain dysfunction. In this, a language dysfunction of some kind can be present right from the onset.

It is a disease of ageing, being more common in more elderly populations, and hence constitutes a lot of people, as the ageing population increases. It may well be one of the more common form of speech and language impairment you see.

Dementia is a result of many different diseases, and the type and severity of problems can result from this heterogeneity. The dementia can be principally cortical (Alzheimer's disease, Pick's disease), or subcortical (Parkinson's disease, Huntington's chorea, progressive supranuclear palsy. It can be due to toxic encephalopathologies (e.g. Wernicke-Korsakoff syndrome), or cardio-vascular disease (e.g. multi-infarct dementia). In can be due to infection (e.g. Creutzfeldt-Jakob disease).

The cause of around 1/2 non-reversible dementia. Diagnosis is usually made between 70-79 years. According to DSM, the symptomatology includes intellectual dysfunctions sufficient to disrupt social behaviour, memory impairment, indication of brain damage and at least one of: problems in abstract thinking, poor judgement, a disorder of higher cortical function (e.g. aphasia, apraxia, agnosia).

Diagnosis can only be made for sure at post-mortem. The brains can be atrophied, and weigh less than 1Kg. The ventricles can be dilated, with atrophy in white and grey matter. The damage primarily involves the frontal and temporal lobes, the hippocampus, para-hippocampus and hippocampal gyrus. Primary motor, somatosensory and visual cortex are relatively spared.

There are also changes in the tissue of the brain, when seen under a microscope. These include neurofibrillary tangles, neuritic plaques and granulo-vacuolar degeneration. These are not seen through out the brain, but are seen only in some regions. Thus granulo-vacuolar degeneration is seen mainly in the hippocampus, while plaques and tangles are seen in the temporal-parietal-occipital junction, and the frontal lobe. These can extend to the sub-cortical regions. All these changes alter the transmissions of nerve impulses. Thus, there is a reduction in the levels of enzymes responsible for the production of acetylecholine, and the pattern of depletion mirrors that of the histological alterations.

The cause of Alzheimer's is not known, thought there is evidence for a hereditary factor; people with a first-order relative with it are four times more likely to develop it them selves. People with Down's Syndrome develop a neuropathology very similar to Alzheimer's in middle age. The problem may also be an exaggeration of normal ageing.

This is rare, and clinically resembles Alzheimer's. The cause is unknown. Onset is usually between 40-60 years, women are affected more often than men. There is cognitive deterioration, but memory is less impaired than Alzheimer's disease, especially in the early stages. This is due to a sparing of the hippocampus in Pick's disease. The first changes are language problems and a wide variety of personality changes, including irritability, depression, socially inappropriate activity, hypersexuality, loss of personal propriety and other disinhibitions. There are no motor abnormalities at the start, though there can be a development of Parkinsonian-type symptoms. Terminally, the patients are mute and immobile, and doubly incontinent.

The brains are reduced in size, which can be seen on a scan. The atrophy can selectively involve frontal or temporal lobes, or both. Within this, anterior temporal regions and orbito-frontal cortex are involved.

There are two characteristics at the cellular (histological level). These are Pick bodies (dense intracellular structures in the cytoplasm) and inflated neurones - enlarged cell bodies with no clear intrusive structure. There is also loss of neurones and a proliferation of microglial cells. No clear involvement of one neurotransmitter system.

A language deficit is present in all stages of the disorder. There is a progressive decline in communicative abilities.

Early stage: speech is fluent, syntactic and well articulated. There are word finding problems (like anomic aphasia?). They have problems naming, and use circumlocutions to try and find the word, but can't use phonemic cues. Phonemic paraphasias are corrected.

Mid-stage: language becomes increasing paraphasic. More errors are not corrected. There are more neologisms, and comprehension is impaired. It can resemble a Wernicke's aphasia or a transcortical sensory aphasia.

Late stage: There is a breakdown of pragmatic function. The patients are non-fluent, echolalic and palilalic, with very impaired comprehension. Somewhat like global aphasia, without the non-verbal cues.

Their problems with 'pragmatics' seems to result from this being a more 'cognitive' use of language - relevance, context, conventions.

As it is hard to know the type of dementia presented, you will sometimes see a dementia described as global or focal. Global is a 'generalised' decline; 'focal' means a progressive problem that targets just one function. Thus progressive aphasia (Mesulam, 1982) described patients with aphasia that was getting worse with no other dementia. A recent review (Westbury and Bub, 1997) identified that this is more common in men than in women (although women out number men in this age range). If the brain damage is unilateral in this condition, it is left hemisphere. Within this, the frontal lobes and temporal lobes are commonly involved. It can occur in association with bilateral damage, which may implicate separate disease processes. Within this, there can also be a selective progressive impairment of semantic processing - semantic dementia (Snowden et al, 1989). Here the only language problem (for a long time) is expressive and receptive vocabulary; they often present with problems remembering the names of people and things. Syntactic and phonological processing is (until much later on ) spared. The damage seems to be focussed on the temporal lobes, especially on the left.

Since the pathology is not known, if atrophy can be seen on a scan, the disease will be shown up by and referred to by this. Thus, frontotemporal dementia is selectively focussed on the frontal and temporal lobes, and this term may well be used until post-mortem evidence is present for Alzheimer's or Pick's disease to be indentified. Both of these, as well as other, non specific progressive damage can lead to global and focal dementias.

It is also worth noting that not all dementias can be classified in terms of their cause; there can be neuronal degeneration without the histological changes typical of Alzheimer's, Pick's disease or Creutzfeldt-Jakob disease.

This results from multiple small infarctions in the cerebral tissue, due to many vessel occlusions. The cases thus vary widely in the presentation. This accounts for 14-20% of dementia cases.

Hypertension is a common cause (aetiology), also other disorders that affect the vascular system (e.g. diabetes, cardiac disease). The infarcts can cover subcortical and cortical regions. It tends to have an abrupt onset, a step-wise deterioration in functions, nocturnal confusion (due to strokes at night), preservation of personality, some focal neurological signs. It can include aphasia, apraxia, and/or dysarthria.

A pathological effect of the outcome of many years of alcoholism. Body stops absorbing vitamins (esp. thiamin, B1) properly. This affects the brainstem, thalamus, mammillary bodies, hypothalamus, and the frontal and association cortices. There are gait problems, eye movement problems, and cognitive changes. There is amnesia for recent events, and new memories can't be formed.

This is a rapidly progressing dementia that leads to death. Some cases are inherited but most forms have no known aetiology. In the variant 'Kuru', seen in New Guinea, it is transmitted by the eating of human brains. In the most common form of Creutzfeldt-Jakob disease (CJD) there is a very rapid progressive dementia leading to death within 6 months. It occurs in older populations. There is a decline in cognitive abilities, with some cerebellar signs, such as unsteadiness (ataxia) and myoclonus (rapid jerks of body). There can be disturbances of colour vision. As the disease progresses there can be fits, and the patient becomes mute, incontinent and bed bound.

In New Variant CJD (NV CJD) the cases are younger (around 30) and the onset and progression slower. Typically the initial signs are psychiatric; anxiety, depression, withdrawing. After 6 months there will be signs of imbalance and dementia.

At post-mortem, there is evidence of spongiform encephopathology; there are literally many hole in the cerebral tissue, like a sponge.

Most common onset in 50-60 years. Progression varies widely across patients, though it tends to be slowly progressive. There may be rigidity and tremor, with an immobile face and slowed movements. Often have a stooped posture and a shuffling gait (small steps). Dementia occurs in 30-39% of cases. There is no known cause. There is a reduced amount of dopamine in the basal ganglia and substantia nigra seen at post-mortem. It can sometimes follow encephalitis, carbon monoxide poisoning, or TBI. The four symptoms are:

Tremor - due to rhythmically alternating contraction of given muscle group, more obvious in distal regions (pill-rolling finger and thumb). Can also affect the face tongue and jaw muscles. Most obvious during rest.

Rigidity - unlike a 'spastic' response (resistance which gives out), the Parkinsonian rigidity is constant against applied pressure.

Akinesia. This means a poverty of spontaeous movements, a loss of normal associated movements (swinging arm when walking) and a slowness of initiation and execution of voluntary movements.

Postural fixation reflex loss. These keep the normal person standing by a system of alternate contractions. This may mean that an upright posture is hard to maintain when sitting, standing or walking.

Parkinson's disease is a very common cause of hypokinetic dysarthria. Treatments target the dopamine system.

Occurs in middle to later life. Starts with a feeling of unsteadiness, unclear speech, personality changes. As it progresses, symptoms include problems with vertical gaze, pseudo-bulbar palsy, dysarthria, rigidity of the neck and upper trunk and mild dementia. Pseudo-bulbar palsy affects the upper motor neurone, i.e. those that descend from the motor cortex. Speech is stiff but the facial muscles don't waste away. The disease prgresses rapidly and the patient is incapacitated within 2-3 years. They have akinesia and a 'mask-like' face as in Parkinson's disease, but no loss of associated movements. The sites of degenerative change include the globus pallidus, sub-thalamic nucleus and the pre-tectal region of the brainstem. The cerbral and cerebellar corices are mainly spared. The cause is unknown. Clinically, it will also result in hypokinetic dysarthria.

This is an inherited disease, an autosomal dominant trait. It begins in adult life (often after people have already had children), and is usually fatal in 10-15 years. Pathologically, there is a loss of neurones in the caudate nucleus and putamen, which are shrunken. The frontal lobes also become atrophic. It is a progressive disease, and there are more choreiform movements with time. Choreiform from chorea, a single sustained muscle movement, producing a short rapid uncoordinated jerk in the trunk, limb, face, tongue, diaphragm etc. They are random and irregular. As the disease progresses, there is facial grimacing, head jerks, weaving movements of the arms and twisting of the body, plus super-imposed voluntary movements (turning an upward jerk of the arm into a head scratch). Gait is very affected. Muscular strength is unimpaired. The initiation of voluntary movements is intact. The patients have hyperkinetic dysarthria, with choeriform movements superimposed on the articulations, with a very variable pattern of interference with phonation, articulation, resonation and respiration. There can be voice arrests, grunting, breathlessness, a strained voice, and hypernasality (not always present). Articulation can be normal and be suddenly disrupted, with consequently jerky speech.