Chapter 11 The nervous system
HIGHER CORTICAL FUNCTION
Examination (Fig. 11.1; Review Box p. 229)
Intelligence
Tests of knowledge and abstract thinking must take account of the patient’s social background.
PROVERB INTERPRETATION
Read out proverbs of increasing complexity and ask for the patient’s interpretation. This assesses both general knowledge and capacity for abstract thinking.
GEOGRAPHICAL ORIENTATION
Problems may have been evident during history-taking: assess formally by asking the patient to draw an outline of his or her country and within it place some of the major cities.
SPEECH
Dysphonia
A defect of volume, typically the consequence of diaphragmatic, respiratory muscle or vocal cord dysfunction.
ASSESSMENT OF DYSPHASIA
Fluency
Questions to ask: Assessment of dysphasiaComprehension
Ask questions of increasing complexity, although still answerable by a yes or no response
WRITING
Test writing by asking the patient to write first simple words then sentences to dictation. All aphasic patients have writing difficulty (agraphia).
PRAXIS
Apraxia is a disorder of skilled movement (whether of the face, tongue or limb) which is not attributable to weakness, incoordination, sensory loss or a failure to comprehend the command:
To assess, start by asking the patient to carry out a particular task. If that fails, ask the patient to copy your own movement and, if still unsuccessful, provide an object (for example, a screwdriver) and ask for a demonstration of its use. A more complex sequence is tested by asking the patient to go through a sequence of related movements.
RIGHT–LEFT ORIENTATION
Start with simple commands, then increase their complexity. A proportion of normal individuals have some problem with right–left orientation.
Primitive reflexes
A number of reflexes may emerge as the result of the disorders affecting higher cortical function.
GLABELLAR TAP
Tap your index finger repetitively on the patient’s glabella. The blink response should inhibit after three to four taps. The response fails to inhibit in Parkinson’s and Alzheimer’s disease.
PALMOMENTAL REFLEX
Apply firm and fairly sharp pressure to the palm alongside the thenar eminence. A positive response results in contraction of the ipsilateral mentalis with puckering of the chin.
POUT AND SUCKLING REFLEXES
A positive pout response consists of protrusion of the lips when they are lightly tapped. A positive suckling reflex consists of a suckling action of the lips when the angle of the mouth is stimulated.
GRASP REFLEX
Elicited by stroking firmly across the palmar surface of the hand from the radial to the ulnar border. In a positive response, the examiner’s hand is gripped by the patient’s fingers, making release difficult or impossible. A foot grasp reflex is elicited by stroking the sole of the foot towards the toes with the handle of a patellar hammer. A positive response results in flexion of the toes with grasping of the hammer (Fig. 11.2).
Clinical application
AMNESIA
Damage to the limbic system leads to failure to learn new memories (antegrade amnesia) plus loss of memory for recent events (retrograde amnesia).
Differential diagnosis: Disorders of higher cortical function and speechDYSARTHRIA
DYSPHONIA
Frequently non-organic. In spastic dysphonia, a form of dystonia, inappropriate muscle contraction, particularly of the larynx, produces strained and strangulated speech.
DYSPHASIA
Non-fluent speech is associated with anterior hemisphere lesions and fluent speech with posterior hemisphere lesions.
AGRAPHIA
Nearly all aphasic patients have agraphia, but many patients with agraphia are not aphasic.
APRAXIA
PRIMITIVE REFLEXES
Review: Assessment of higher cortical functionTHE PSYCHIATRIC ASSESSMENT
Make sure that the patient understands who you are, and the purpose of the interview. Privacy is particularly important when sensitive issues are being explored. To begin with, avoid making notes, as this can detract from the relationship you are trying to establish with the patient. During this preliminary phase, observation of the patient’s posture, gestures and facial expression may provide information regarding mood and feeling. The depressed patient appears apathetic, has little expression and may well be reluctant to discuss the history. The agitated patient is restless.
History of present condition
This proceeds in much the same way as history-taking from a patient with a physical complaint. Indeed, physical symptoms often predominate in those individuals with a primary psychiatric illness. Try to establish when the patient last felt well, as a means of determining the overall length of the history and as a means then of establishing the chronological order of subsequent symptoms. If necessary interrupt the patient if he or she digresses into other areas, for example current social issues, although making clear that you are interested in these issues, and will wish to return to them later. Sometimes directive questions are needed to focus the patient’s attention on a particular symptom, for example headache, in order to explore that symptom in greater detail. As the history proceeds, open questions will be partly replaced by closed questions, answerable by a simple yes or no response. Sometimes signs of emotional distress may appear as certain issues are covered. Rather than ignoring these, gently probe them, even if this temporarily disturbs the course of the history.
Quite often, patients only indirectly refer to stressful issues by giving oblique reference to them in the course of describing their physical symptoms. Try to pick up the cues and develop the relevant issue. Failure to detect them may well deter the patient from discussing them further.
Many symptoms are common to both physical and psychiatric illness but others are more specifically within the territory of psychiatry.
Specific symptoms
MOOD
Enquire whether the patient, or a relative, has noticed any mood change. A particularly valuable question when screening for depression is whether the individual has lost pleasure in normal activities (anhedonia). Supplementary to this will be enquiries regarding sleep pattern, loss of libido and suicidal ideation. Sometimes the patient denies flattening of mood, when that is all too evident from the interview. Such discrepancies should be carefully recorded.
Patients will usually complain of anxiety but sometimes its somatic manifestations, for example palpitations, sweating and tremulousness, predominate. The anxiety may be chronic and spontaneous or be triggered acutely by a specific stimulus – phobic anxiety.
Patients seldom complain of euphoria – a feeling of limitless physical and mental energy. There is likely to be a pressurised, manic quality to the patient’s conversation, coupled with physical restlessness.
Questions to ask: Psychiatric assessmentABNORMAL THOUGHTS
These will be elicited only by sensitive questioning. The patient can be understandably reluctant to reveal certain abnormal thoughts. It may be apparent from the interview that the patient’s thought pattern is difficult to follow or that abnormal thoughts have pervaded the conversation. Ask patients about paranoid ideas, in other words, whether they feel people are against them. Ask patients whether certain thoughts or ideas regularly intrude into their thinking, or whether they believe their thoughts are being interfered with or influenced by external agencies. Thought disorders include delusions and obsessiveness.
Delusions
These are beliefs that can be demonstrated to be incorrect but to which the individual still adheres. Members of the Flat Earth Society are deluded. Often there is an element of reference, in other words that actions or words are directed specifically at that individual even if they appear on a global platform, for example television. Paranoid delusions contain a persecutory element. Delusions of worthlessness are particularly associated with depressive illness.
Symptoms and signs: Somatic and psychic symptoms of anxiety and depression
| Anxiety | Depression | |
|---|---|---|
| Somatic | Palpitations | Altered appetite |
| Tremor | Constipation | |
| Breathlessness | Headache | |
| Dizziness | Bodily fatigue | |
| Fatigue | Tiredness | |
| Diarrhoea | ||
| Sweating | ||
| Psychic | Feelings of tension | Apathy |
| Irritability | Poor concentration | |
| Difficulty sleeping | Early-morning waking | |
| Fear | Diurnal mood swing | |
| Depersonalisation | Retardation | |
| Guilt |
Obsession
These are recurrent thoughts which often result in the performance of repetitive acts (compulsion). The patient is aware that they are inappropriate but cannot resist returning to them or acting upon them. Examples of obsessional thought include convictions that a particular individual is antagonistic or that a spouse is unfaithful.
ABNORMAL PERCEPTIONS
These are auditory or visual phenomena of which other individuals are not aware.
Hallucinations are experiences that have no objective equivalent to explain them. They are predominantly visual or auditory but can occur in other forms, for example, of smell or taste in patients with complex partial seizures. Visual hallucinations can be unformed, for example an ill-defined pattern of lights, or formed, the individual then describing people or animals, often of a frightening aspect. Visual hallucinations are more often a feature of an organic brain syndrome (e.g. delirium tremens or an adverse drug reaction) than a functional psychosis, e.g. schizophrenia. Auditory hallucinations are also either unformed or formed. They are found more often in the functional psychoses than in organic brain disease. The voices can take on a persecutory quality in schizophrenia and an accusatory element in depression. In déjà vu and jamais vu, intense feelings of a relived experience or a sensation of strangeness in familiar surroundings occur, respectively. Both can be a feature of everyday life but when pathological are usually epileptic. Illusions are misinterpretation of an external reality – all of us have this when watching a magician at work. In depersonalisation, the individual feels a detachment from the normal sense of self, in derealisation a detachment from the external world. Both occur in neurotic illnesses but also, periodically, in normal individuals.
The assessment of higher cortical function has already been discussed. It is necessary to distinguish cognitive impairment due to dementia, from cognitive impairment due to delirium. In the latter there is clouding of consciousness, usually manifested as reduced awareness of, or response to, the environment.
The family history
Begin by obtaining details of the patient’s father and mother, in terms of their current age (or age at death), their own quality of health, whether they had any history of psychiatric disorder and the quality of the patient’s relationship with them. Ask similar questions about the patient’s siblings. Questions regarding the patient’s own children are usually included in the personal history. Genetic factors are particularly strong in schizophrenia and manic–depressive psychosis.
The personal history
CHILDHOOD
It is unlikely that the patient will have accurate details of birth or early development unless there were particular problems with them. A direct question to the patient regarding whether he or she was happy or unhappy in childhood is useful. Some ‘happy’ responses turn out to be rather less so with further delving. If there is an expression of remembered unhappiness, explore it further in terms of relationships with parents and any physical illness.
SCHOOLING AND FURTHER EDUCATION
Establishing the details of this is helpful in forming an assessment of the patient’s premorbid intelligence. At the same time enquire about friendships or a tendency to isolation and about teasing or bullying.
SEXUAL DEVELOPMENT
For female patients, enquire about the age of the menarche and how they attuned to adolescence in terms of menstruation and sexuality. For men, discussion should include whether their sexuality could be discussed in the home and how they acquired their sexual experience. Further issues relating to sexual development, for example homosexual experiences, are best left, at this stage, to the patient to raise.
MARITAL HISTORY
An overall outline here includes the age of the spouse, when the marriage occurred, the overall quality of the relationship, the state of the sexual relationship and details of any children.
OCCUPATIONAL HISTORY
Ask how many jobs the patient has had, reasons for leaving previous posts, the quality of relationship in the work place and the level of job satisfaction. If there has been one or more periods of unemployment, explore what effect this has had on the patient’s overall welfare.
PAST MEDICAL HISTORY
This follows the usual pattern, and includes history of physical and mental illnesses if these have occurred.
DRUG HISTORY
Determine alcohol consumption, but be aware of the possibility that the figure does not correspond to actual intake. Features suggesting alcohol dependency include early-morning drinking, morning vomiting, taking a drink before an interview, erratic work attendance and drinking in isolation. Ask about narcotic exposure, the use of softer drugs such as cannabis and exposure to tranquillisers. If the patient is using codeine derivatives, ascertain for what purpose and the dosage.
PERSONALITY PROFILE
Evidence suggesting changing personality and mood is often better provided by colleagues, relatives or friends than by the patient. Questionnaires exist for the assessment of personality but even without them the patient’s attitude and behaviour, in terms of work and social relationships, personal ambitions, drive, level of independence and authority and response to stress, will indicate the patient’s maturity.
HEADACHE AND FACIAL PAIN
Headache
Often the history suffices to recognise the more serious causes. Factors to determine include:
Examination of a headache patient is often normal but fundoscopy is essential. Scalp tenderness is seen in some patients with tension headache and tenderness of scalp vessels is a feature of cranial arteritis.
Differential diagnosis: Headache
Questions to ask: Facial painTHE CRANIAL NERVES
First cranial nerve (olfactory)
EXAMINATION
Apply a smell to each nostril, using a squeeze bottle or impregnated strip. Ask the patient to identify the smell or describe its characteristics.
Symptoms and signs: Disturbances of olfactionSecond cranial nerve (optic)
EXAMINATION
Visual acuity
Colour vision
For screening purposes, use Ishihara test plates, testing each eye separately. Ask whether the patient is aware of having a congenital colour vision defect.
Visual fields
Fundoscopy
Preferably performed in a darkened room. Ask the patient to fixate on a distant target. If severely myopic, it sometimes helps to perform fundoscopy with the patient wearing his or her glasses. Look for:
CLINICAL APPLICATION
Optic atrophy
Occurs with any process that damages the ganglion cells or the axons between the retinal nerve fibre layer and the lateral geniculate body. Pallor of the disc follows, often predominating in the temporal aspect.
Papilloedema
Usually bilateral, although sometimes asymmetrical. Successively there is swelling of the nerve fibre layers (best seen with a red-free light), hyperaemia of the disc with loss of its definition and the disappearance of retinal venous pulsation. Eventually there is engorgement of the retinal veins, flame-shaped haemorrhages and cotton wool spots (the last due to retinal infarction). Visual field changes include enlarged blind spots and arcuate defects. Peripheral constriction is a late complication.
Retinal vascular disease
Glaucoma
Can occur in a primary form or secondary to various ocular pathologies. Changes in the optic disc include enlargement of the physiological cup. Retinal nerve fibre atrophy develops, producing arcuate field defects.
Symptoms and signs: Visual field defects
| Absolute central scotoma | Area around fixation in which there is no appreciation of the visual stimulus |
| Relative central scotoma | Area in which an object is detected but its colour is reduced (desaturated) |
| Centrocaecal scotoma | A field defect extending from fixation towards the blind spot |
| Bitemporal hemianopia | Involvement of the temporal halves of both fields |
| Homonymous hemianopia | Involvement of the temporal half of one field and the nasal half of the other |
Chiasmatic lesions
Typically due to a pituitary tumour, craniopharyngioma or meningioma. The resulting field defect is a bitemporal hemianopia, typically asymmetric.
Optic tract and lateral geniculate body lesions
Uncommon. Produce incongruous (i.e. non-matching) homonymous hemianopias.
Optic radiation and occipital cortex lesions
Produce homonymous defects which become increasingly congruous the more posterior the lesion. Occipital lobe lesions produce congruous defects that can be total, quadrantic or scotomatous. An isolated homonymous hemianopia is usually due to vascular disease affecting the occipital lobe.
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