9. Speech disorders following head injury

Abstract

THE two most frequent forms of speech disturbance encountered in patients with severe or moderately severe head injury, are disorders of language (dysphasia) and disorders of articulat ion (dysarthria). There may also be difficulty in voicing (dysphonia) and/or hearing impairment. Disorders of articulation take varied forms depending on the site of the lesion. Dysarthria is characterized by impaired movement or coordination of the organs of articulation (lips and tongue) associated with slurring of consonants and a disturbance of rhythm, stress, intonation, and speed of delivery. In severe cases speech may be quite unintelligible. Some mild cases, on the other hand, sound as if they have a foreign accent like an English boy I saw in Oxford following a head injury whose speech sounded American. Dysarthria may be associated with disturbance in voice production depending on which nerves are affected, as in the case of another young man I saw, whose chief complaint was gross nasality and escape of air down the nose combined with intermittent voicing. Disorder of language which we call dysphasia (or where there is complete absence of spoken language, aphasia) affects the whole process by which meanings are comprehended and expressed. It can cover all modalities, spoken, written, or gestural. I emphasize this as people sometimes think that if spoken language is disturbed the patient could make his wants known by gesture or writing (with the left hand if need be) but this is not always feasible. Five major categories of aphasia have been defined according to the degree of severity and which sensory modalities are involved:-1. Simple aphasia--slight reduction in all modalities. 2. Aphasia complicated by visual involvement affecting reading and writing. 3. Aphasia complicated by sensorimotor involvement affecting particularly executive speech. 4. Severe reduction in all modalities, particularly visual, and with dysarthria. 5. Irreversible aphasia with almost complete loss of language skills. Nearly all patients show some degree of receptive difficulty in addition to disorders of expressive language. These disorders of speech and language may be complicated in head-injured patients by symptoms of organic mental change such as loss of memory, difficulty in concentration, mental fatigability, irritability, and change of personality. There may be other deficits associated with damage to the central nervous system such as visual or hearing impairments and psychological reactions to the disability; anxiety, confusion and depression and emotional shock. All of these may serve to hamper the patient's attempts to communicate effectively.