Apraxia vs Dysarthria
A speech disorder, or an impediment is where the normal speech pattern is affected, and verbal communication is adversely affected, or completely nullified. It may range from stuttering, cluttering, muteness to voice disorders. The causes for these conditions may be cerebral in origin, or of the cerebellum, may be of the muscles or psychological. Here, we will discuss on the site of origin, presentations, and management strategies, which vary and overlap in apraxia and dysarthria.
What is Apraxia?
Apraxia is a disorder of the brain and the nervous system, in which the person is unable to perform tasks and movements even though the auditory input, comprehension of the task, psychological willingness, and learning is all present. This is due to damage to the brain, which may be due to brain tumour, neurodegenerative disease, stroke, head trauma, etc. This may occur in conjunction with aphasia, which is the cerebral incapability to understand (auditory- Wernicke’s area), or to vocalize (motor-Broca’s area). In apraxia, there is difficulty to put word together in the correct order, or to reach for the correct word, or to enunciate longer words, although they can use shorter words put together (“Who are you?”). Also, the writing is better than the speech in these individuals. This is managed through speech and language therapy, occupational therapy and treating depression. This can get complicated with learning problems and social problems.
What is Dysarthria?
Dysarthria occurs due to in-coordinate muscle actions leading to the difficulty in pronunciation of words. This may occur due to a problem in the brain (tumour, stroke), or due to nerve damage in trauma/surgery to the neck /face, or neuromuscular cause like myasthenia gravis, Parkinson’s disease, multiple sclerosis, etc, or due to an exogenous cause like alcohol intoxication. These individuals, have difficulty in speaking certain words, and it will seem as if they are mumbling, or speaking in a whisper, or speaking in a stuffy/ nasal voice. They are managed with speech and language therapy, also treating associated psychological ailments. They can also use communication assist devices. As a complication, they also can develop aspiration pneumonia.
What’s the difference between Apraxia and Dysarthria?
Both apraxia and dysarthria have a nervous system aetiology and difficulty in communicating. The investigative methods, management strategies, and complications are common in both. Apraxia is of cerebral origin, whereas dysarthria is cerebral/neural/ muscular, or any combination in between. Apraxia is inconsistent, unpredictable, with islands of clear speech. Dysarthria is consistent, predictable and without islands of clear speech. All aspects of speech are affected in dysarthria, but only articulation is affected in apraxia. In dysarthria, there is a change in muscle tone, whereas there is no such change in apraxia. In apraxia, increased speech rate increases the intelligibility, whereas it has the opposing effect in dysarthria. Dyspraxia is associated with aspiration pneumonia as a complication, whereas dysarthria has no such relevance.
These two have to be understood as separate entities, though the results are a bit similar. But a careful investigator would find aspects, which we have described earlier which separate out the two. The management for these two is similar in that the causative mechanisms are irreversible, and only compensatory efforts can be taken.