Arm drift

A very useful but non-specific sign in clinical neurology is termed 'drift'. A positive sign suggests some underlying abnormality in nervous function and is an indication for performing a more detailed neurological examination.

Examination sequence

□ Ask the patient to close the eyes and outstretch die limbs, placing palms uppermost and the fingers extended and adducted, and then to maintain this position.

Normally the limbs do noi drift with eyes closed. Abnormality may involve a subtle change in finger position (e.g. a slow flexion) or a more gross drift downwards or pronation of the whole arm.

Speech

Much may be learned about the patient's speech and language function during history-taking (p. 17). Speech disorders may be divided into two main groups:

1. Disorders of articulation (dysarthria) and phonation (dysphoria).

Romberg Test
Fig. 6.6 Romberg's test for position sense. The patient can stand with feet together and eyes open 12 bul falls with eyes closed tH. in contrast, the patient with a cerebellar lesion cannot stand with feet together and eyes open E].

Brocas Central Wernickes area sulcus area

Brocas Central Wernickes area sulcus area

Romberg Test Physiology

fasciculus

Fig. 6.7 The main language areas.

fasciculus

Fig. 6.7 The main language areas.

TABLE 6.12 Examination of speech and language

Spontaneous speech

Naming objects, concepts

Articulation

Comprehension of spoken commands

Fluency

Repetition of spoken phrases

Paraphasias

Reading aloud

Grammar

Handwriting

Syntax

2. Disorders of language areas in the dominant hemisphere (dysphasia).

If a deficit of speech is evident a more thorough examination should be undertaken. By careful examination of speech and language it is often possible to localise the causative lesion.

Anatomy

The language areas are situated in the dominant cerebral hemisphere. In the vas1 majority of right-handed people the left hemisphere is dominant. About a third of left-handers have a dominant right hemisphere; the others have either left-sided or bilateral language localisation. The main language areas are shown in Figure 6.1.

Brocu's area (the inferior frontal region) is concerned with the generation of motor programmes for the production of words or parts of words (phonemes).

Wernicke!v area lies in the posterior temporal lobe and the adjoining parietal region and is concerned with the comprehension of language and the selection of words to Convey meaning.

Examination sequence (Table 6.12)

□ Spontaneous speech: Assess Ihe output of spontaneous speech, lluency and use of inappropriate words (paraphasias and neologisms) during conversation. If dysarthria is suspected, ask the patient to repeat a phrase which requires precise articulation (e.g. 'Wesl Register Street').

H Naming of objects: Ask the patient to name a shown object (e.g. a comb or a pen). The test can be made more difficult hy asking the patient to name an object or a concept that is described but not shown. Comprehension of spoken speech: Assess comprehension of spoken speech by asking the patient to carry out commands. Staged commands (e.g. 'pick up the blue card, fold it in half and put it under the while card') help bring out subtle defects. A collection of coins can provide suitable objects for similar arrangement tasks. It is important to avoid giving visual clues.

Ask the patient to say simple sentences such as 'Today is Tuesday'. This is often sufficient to detect repetition failure due to conduction dysphasia.

□ Ask the patient to read aloud from a book or paper. This may reveal an associated dyslexia.

□ Examine the patient's handwriting. This cannot be assessed if there is a motor deficit affecting the writing hand. Errors of form, grammar and syntax may be found in association with dysphasia, indicating a disorder not only of speech but more globally affecting language function.

Common abnormalities

Dysarthria. Dysarthria may be caused by purely mechanical factors such as ill-fitting dentures, hut it is usually due to weakness or impaired coordination of the orolingual muscles concerned with the production of consonants (see Table A. 13). Dysarthric speech is indistinct and difficult for the listener to discern. However, ils grammatical construction is normal, and the patient's comprehension of spoken

TAB LE 6.13 Causes of dysarthria a nd dysphonia

Mechanism

Example

Weakness of facial and tongue muscles

Myasthenia gravis

Lesions of lower brain stem (bulbar palsy)

Motor neurone disease

Bilateral corticospinal tract lesions above

Multiple lacunar infarcts

the pons

Impaired control of phonation and articulation

Parkinsonism

Imprecise motor control systems

Cerebellar lesions

Impaired larynx function

Recurrent laryngeal nerve

palsy

and written language is retained. With cerebellar deficits the dysarthria has a slurred quality with imprecise control of word length and tonal inflection, giving it a drawling, 'sing-song' quality Dysarthria is often evident during conversation with the patient while the history is being taken.

Elevation of the soft palate is used to close off the nasopharynx for the production of explosive consonants I'll' and 'g'). Palatal weakness or anatomical defects in the palate cause 'nasal' speech with failure to produce these sounds correctly. For example, when such a patient tries to say the word 'egg' it is pronounced as 'eng'.

Dysphoria. The production of tones in speech is achieved by movement of expired air through the larynx. Vibration of the vocal cords produces the frequency changes used in speech and singing. Poor respiratory function may cause dysphasia, but more typically it is the result of laryngeal problems, causing hoarseness of the voice, often with reduced speech volume.

Dysphasia. Difficulty with language function is called dysphasia. Damage to Broca's area causes:

• reduced number of words used

• poorly articulated and non-fluent speech

• errors of grammar and syntax.

Such speech has a clipped, telegrammatic quality, but if the lesion is relatively localised, comprehension of spoken and written language is usually preserved.

With dysfunction in Wernicke's area, the output of spontaneous speech may be normal or increased, the speech fluent and the articulation of phonemes is usually intact. However, the speech may contain:

• incorrect words (verbal paraphasias)

• incorrect letters (literal paraphasias)

• nonsense words (neologisms).

Conduction dysphasia. In this disorder the patient is unable to repeal phrases or words spoken by the examiner. The causative lesion lies in the perisylvian area with damage to the arcuate fasciculus of tibres,

Global dysphasia. In this condition there are elements of both anterior (Broca) and posterior (Wernicke) dysphasias. This results from large lesions in the middle cerebral artery territory. It may be so marked as to abolish speech completely (aphasia).

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Responses

  • awet
    How to assess arm drift?
    7 years ago
  • agamennone padovano
    When assessing arm drift, how long are the arms held out?
    1 year ago
  • fatima
    How to check for arm drift?
    10 months ago
  • Luca
    When we do arm drift motion check in medical assessment?
    5 months ago
  • cain
    What is arm drift called?
    2 months ago

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