Dysarthria / Aphasia:
Dysarthria is a motor speech disorder resulting from neurological injury of the motor component of the motor-speech system and is characterized by poor articulation of phonemes (cf. aphasia: a disorder of the content of language). In other words, it is a condition in which problems effectively occur with the muscles that help produce speech, often making it very difficult to pronounce words. It is unrelated to any problem with understanding cognitive language. Any of the speech subsystems (respiration, phonation, resonance, prosody, and articulation) can be affected, leading to impairments in intelligibility, audibility, naturalness, and efficiency of vocal communication.
Individuals with dysarthria may experience challenges in the following:
- Vocal quality
- Breath control
Examples of specific observations include a continuous breathy voice, irregular breakdown of articulation, monopitch, distorted vowels, word flow without pauses, and hyper nasality.
Aphasia is a combination of a speech and language disorder caused by damage to the brain that affects about one million individuals within the US. Most often caused by a cerebral vascular accident (CVA), which is also known as a stroke, aphasia can cause impairments in speech and language modalities. To be diagnosed with aphasia, a person's speech or language must be significantly impaired in one (or several) of the four communication modalities following acquired brain injury or have significant decline over a short time period (progressive aphasia). The four communication modalities are auditory comprehension, verbal expression, reading and writing, and functional communication.
The difficulties of people with aphasia can range from occasional trouble finding words to losing the ability to speak, read, or write; intelligence, however, is unaffected. Aphasia also affects visual language such as sign language. In contrast, the use of formulaic expressions in everyday communication is often preserved. One prevalent deficit in the aphasias is anomia, which is a deficit in word finding ability.