On the basis of the patient’s symptom and the history-taking, the doctor may suspect that a disorder involving the higher cerebral functions may be involved other than, or besides, the previously-mentioned dysphasia. In a number of cases such a disorder is already clear on the first encounter and targeted examination of cerebral function is unnecessary or impossible (for example, in the case of a child with a fever-induced delirium). There are, however, patients in whom careful investigation of a possible impairment is necessary. Higher cerebral function impairments can act as warning signals, as in a number of cases they can be the first sign of a neurological condition. Particularly in cases where the condition can be treated (cerebral tumours, chronic subdural haematoma etc.) early recognition is important for the patient. There are also various neurological conditions in which cortical function impairment remains the only symptom for a long period of time (for example, Alzheimer’s disease) and where imaging investigation (CT, MRI) reveals no abnormalities.
It is understandable that many (general) physicians strongly resist specifically examining their patient’s cerebral functions. The patient could, after all, feel hurt (‘The doctor thinks I’m mad’) or may be ashamed of the mistakes they make during the examination. If, however, you believe that this examination is in the patient’s own interest because you wish to base your further course of action on any abnormal findings, you should try to explain this to the patient. In general, neuropsychological examination is used to investigate the following cerebral functions:
- consciousness and alertness
- orientation to time, place and person
- memory and imprinting
- language functions
- gnosia
- praxis
- judgement and affect
- specific impairments in consciousness.
Impairments in these functions can arise independently of each other. All functions should therefore be examined. An impairment in function such as consciousness and attention can also cause apparent impairments in another function such as orientation and language, without this function truly being involved.
Procedure of the examination
It goes without saying that the patient must be prepared to cooperate with the examination. It is also sometimes forgotten that poor motivation can be part of a neurological disorder.
1. Consciousness and alertness
To carry out the examination, the patient must have a sufficiently alert state of consciousness. In addition, they must be and want to be sufficiently alert to answer your questions and carry out your tasks. Consciousness impairment can manifest itself in many different ways (refer to the section ‘The unconcious patient’). For example, the patient may be confused or anxious.
2. Orientation in place, time and person
With the exception of cases where the patient is severely disoriented as the result of impaired consciousness, impaired orientation generally indicates loss of memory.
- Does the patient give the impression that they know where they are at the moment and how they came here? If in doubt, ask the patient directly.
- Ask the patient approximately what time it is, what part of the day it is, which day, month and year it is.
- Ask the patient if they know who you are and if they know who the family members are who have accompanied them (if any). If the patient cannot recall some people’s names, it may indicate nominal aphasia, as part of (early) dysphasia.
3. Memory and imprinting
Without a properly-working memory, a wide range of impairments in mental activities can arise: for a large number of these activities, we use knowledge stored in the memory. Memory impairments can arise in the long-term memory, in which information from the recent or far past is stored, or in the immediate working memory, in which information is stored for a short period of time (imprinting).
The long-term memory
- During the history-taking you should also ask about the patient’s past (medical) history and their use of medication. This will already give you an impression of the patient’s long-term memory. Take note of any inconsistencies, gaps, repetitions or hesitations.
- You can also ask the patient whether they have noticed that their memory has deteriorated recently.
- Tell the patient that you are going to examine their memory.
- Ask specific questions about famous people (royal family, film stars, government leaders, depending on the patient’s interests).
The immediate working memory
- Reproducing numerical series: slowly read out a series of numbers and the patient must repeat them immediately after you.
4.7.2 3.7.6.9.2.5 8.3.7 5.3.8.1.9.6 6.4.2.9 3.7.4.8.9.2.6 7.1.3.6 6.9.2.8.4.7.1
Under normal circumstances patients between 15 and 55 years old can reproduce 6 to 7 numbers, and those over 55 years of age can reproduce 5 to 6 numbers. If the patient reproduces fewer numbers and does not seem very stressed, diffuse cerebral damage or damage to the dominant (usually left) hemisphere may be possible.
- Reversing numerical series: you now read out a series of numbers which the patient should immediately repeat in the reverse order. ‘So, I say 8.6, for example, and you would say 6.8’
3.7.5 3.1.5.4.9 9.2.6 7.6.9.2.3 4.3.5.9 8.5.7.2.4.9 7.4.8.1 2.5.1.9.7.3
Under normal circumstances a patient between 15 and 55 years of age can reproduce 4 to 5 numbers in reverse order, and patients over 55 years of age can repeat 3 to 4 numbers in reverse order.
Both reproducing and reversing numerical series is possible if the immediate working memory is intact (in the case of a common severe memory disorder, Korsakoff’s syndrome, the immediate working memory is barely affected).
- Finally, you list 3 numbers which you ask the patient to remember.
Later, during the course of the conversation, you ask the patient whether they still remember the numbers. You can also hide a number of objects and ask the patient to pay close attention as you will later ask them where the objects are. This test investigates long-term memory function.
4. The language functions – refer to the section ‘The voice, speech and language’.
5. Gnosia
Agnosia refers to the inability to recognise sensory impressions, in other words the patient can see or feel an object, but cannot name it, in the absence of dysphasia or aphasia, severe dementia, retardation or negativism.
- Ask the patient to close their eyes and place a small object in their hands (key, coin, paper clip). Ask them to name the object. If the patient is unable to do so, it is known as somatosensory agnosia.
- You can also trace a number on the patient’s hand using the end of a pen, and ask the patient to name the number.
- Another test is to ask the patient to close their eyes and then name which part of their body you are touching. For example, the left shoulder, the right hand, the left hand etc. Sometimes this does not pose any problem to the patient, but when you touch both knees at once it may happen that the patient can only name one. This is called tactile extinction and indicates a parietal lesion.
- Show the patient colours, objects or pictures and ask them to name them. If they find it impossible to name them or describe them, and the patient is unable to point out an object (for example one on your desk) after you have asked them to do so, they are most probably suffering from visual agnosia rather than nominal aphasia.
There are a few rarer forms of agnosia which will be mentioned below for the sake of completeness.
Anosognosia: the failure to recognise one’s own disease (for example, paralysis). This should not be confused with denial or not wanting to know.
Prosopagnosia: the inability to recognise familiar faces.
Acoustic agnosia: the inability to recognise familiar sounds.
6. Praxia
Apraxia describes the inability to carry out or imitate simple actions, in the absence of any impairment to motor function or comprehension. As with agnosia, there are various forms of apraxia. A distinction should be made between ideational and ideomotor apraxia. The difference is comparable with the difference between sensory and motor aphasia. With ideomotor apraxia the patient is well aware of which action they have to carry out. The pattern of the action is intact, but the patient still makes mistakes which they keep trying to correct. With ideational apraxia the individual components of the action are carried out correctly, but the sequence is ineffective.
- Ask the patient make the sign of a cross, to clench their fist threateningly, to salute, to wave, to mimic brushing their teeth, to comb their hair etc. If this is not possible in response to a verbal request, carry out the action yourself and ask the patient to imitate you.
- Ask the patient to carry out the actions with both the right hand and left hand.
- Give the patient a number of tasks to carry out one after the other. For example: ‘Here is a sheet of writing paper and an envelope. Fold the paper so that it fits in the envelope. Place it in the envelope. Seal the envelope and then give it to me.’
There are various forms of apraxia, such as dressing apraxia (difficulty getting oneself dressed) and constructive apraxia (difficulty drawing shapes or making a puzzle), in which the cause is more likely to be an impairment in the body schema or spatial awareness, respectively; both cases are more a form of gnosia than of praxia.
7. Judgement and affect
During the examination you will already have formed an impression of the patient’s insight into their condition. You will also have an idea of the degree to which the patient is affected by their illness. A wide range of symptoms does not necessarily indicate an organic or non-organic disorder. Extreme indifference may be a fundamental characteristic of a frontal lobe syndrome, while compulsive laughter or crying may indicate a pseudobulbar condition.
8. Specific disturbances of consciousness
These include a number of abnormalities which can also indicate cerebral damage.
Hallucinations.
If the patient has sensory experiences which do not correspond with reality, these experiences are termed hallucinations. A patient may recognise a hallucination for what it is, for example in the case of an aura preceding a migraine or an epileptic fit. If the patient does not recognise the hallucination as such, it usually does not suggest an organic abnormality. Hallucinations associated with intoxication form an exception.
Delusions.
If a patient has thoughts that do not correspond to reality, this is referred to as a delusion. The classic example of a delusion is a paranoid delusion. The patient is convinced that something or someone is out to harm them. Delusions do not suggest an organic cerebral condition.
Twilight state.
On the surface, the patient’s state of consciousness appears intact, but in fact they are only able to carry out automatic actions. More complicated tasks are not understood or not carried out. This twilight state can be the result of metabolic disorders (for example a diabetic precoma) and intoxications (e.g., benzodiazepines) and is seen after or during an epileptic seizure and in someone who is sleepwalking.
Delirium.
If the patient is in a sort of twilight state and also displays very restless motor behaviour and appears to have frightening thoughts or experiences, the state is known as delirium. The most well-known example is fever-induced delirium in a child whose body temperature has risen suddenly. Delirium can occur with intoxications, cerebral contusion or meningitis.
The examination described here can be used as a preliminary informative examination. Abnormal findings should be interpreted with caution. You should, for example, always ask yourself whether, given the patient’s past history, you can expect him or her to understand your questions and tasks. A far more extensive examination is possible.
If the patient makes no mistakes during the entire examination, a condition involving higher cerebral functions is unlikely.