DYSARTHRIA AND SPEECH DISORDERS

Besides dysarthria, three other types of speech disorders should be considered here: dysphasia, cerebellar speech, and extrapyramidal speech. In each case, the anatomic location in the nervous system is fairly specific.

DYSARTHRIA AND SPEECH DISORDERS

Dysarthria

This may be due to a lesion at the end organ (muscles of the mouth and tongue), the myoneural junction, the peripheral branches of the fifth (trigeminal) and twelfth (hypoglossal) cranial nerves, the brainstem, or the cerebrum.

1. End organ. Hypertrophy of the tongue from myxedema, carcinoma of the tongue, and painful lesions of the mouth and tongue may cause speech difficulty. Inability to swallow may leave saliva and food in the mouth and interfere with speech. The facioscapulohumeral form of muscular dystrophy may cause dysarthria.
2. Myoneural junction. Myasthenia gravis, a treatable form of dysarthria, should always be ruled out.
3. Peripheral nerve. Hypoglossal nerve damage from trauma and severing of the motor portion of the trigeminal nerve in trauma and surgery are the principal lesions here.
4. Brainstem. Poliomyelitis, Guillain–Barré syndrome, disseminated encephalomyelitis, brainstem gliomas, and basilar artery occlusions are the most important lesions to recall in this category.
5. Cerebrum. Any disorder that may cause hemiplegia from cerebral involvement may cause dysarthria and pseudobulbar palsy. Cerebral thrombi, emboli, or hemorrhages are perhaps the most significant of these. Frontal lobe tumors or abscesses may be the cause here. Diffuse cerebral diseases such as alcoholism, Huntington chorea, and general paresis may cause dysarthria, but they are more likely to cause other speech disorders.

Cerebellar Speech

This maybe scanning or staccato (clipped). Multiple sclerosis is often the first condition to consider, but the hereditary cerebellar ataxias (e.g., Marie ataxia), alcoholic cerebellar atrophy, syphilis, and cerebellar tumors may also be the cause.

Dysphasia

In this condition, words cannot be pronounced properly (motor dysphasia), there is difficulty naming objects (nominal aphasia), or the words cannot be placed properly in a sentence (syntactic aphasia). In determining the etiology, it is not important to know the exact location of the lesion in the cerebrum because any disease of the cerebrum may cause aphasia or dysphasia. Cerebral hemorrhages, thrombi, emboli, and tumors or other space-occupying lesions are the most important ones to remember. The others are listed on page 362 (memory loss).

Extrapyramidal speech

This is the monotone, rapid, dysarthric speech of paralysis agitans, but it may be found in cerebral palsy, Wilson disease, or Huntington chorea. The last two conditions may also have a jerky speech or dysarthria.

Approach to the Diagnosis

Dysarthria without other symptoms or signs requires that myasthenia gravis be ruled out with a Tensilon test and psychometrics be done to rule out hysteria. In the presence of other neurologic signs, speech disorders require a thorough neurologic workup with an EEG, skull x-ray, and CT scan or MRI of the brain; a spinal tap or arteriogram may be indicated. The clinician should remember that dysarthria may be only the first sign of a serious neurologic disease such as multiple sclerosis, Wilson disease, lupus erythematosus, or chronic alcoholism; therefore, close follow-up is important.

Other Useful Tests

1. Neurology consult
2. VDRL test (neurosyphilis)
3. Acetylcholine receptor antibody titer (myasthenia gravis)
4. Brainstem evoked potentials (multiple sclerosis)
5. Carotid scans (carotid insufficiency or thrombosis)
6. Serum copper and ceruloplasmin (Wilson disease)
7. Spinal tap (multiple sclerosis, neurosyphilis)
8. EEG (intermittent dysarthria, epilepsy)
9. Four-vessel cerebral angiography (cerebrovascular disease)
10. Drug screen (drug abuse)

Copyright Details: Differential Diagnosis in Primary Care, Copyright © 2007 Lippincott Williams & Wilkins.

Other Book Chapters Related to Speech symptoms

Read excerpts from these other book chapters:

Copyright Details: Differential Diagnosis in Primary Care, Copyright © 2008 Williams & Wilkins.

More About Causes of Speech symptoms

• Back to symptom: Speech symptoms: Introduction (review 566 causes)
• Next Book Extract About Speech symptoms: Dysarthria (Handbook of Signs & Symptoms (Third Edition))
• All Book Extracts: All Online Book Extracts for Speech symptoms

More About This Book: Title: Differential Diagnosis in Primary Care Authors: R. Douglas Collins Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 0-7817-6812-8