Dysarthria is a motor speech disorder. It results from impaired movement of the muscles used for speech production, including the lips, tongue, vocal folds, and/or diaphragm. The type and severity of dysarthria depend on which area of the nervous system is affected. Dysarthria that has progressed to or presents as a total loss of speech may be referred as anarthria. Neurological injury due to damage in the central or peripheral nervous system may result in weakness, paralysis, or a lack of coordination of the motor-speech system, producing dysarthria. These effects in turn hinder control over the tongue, throat, lips or lungs such as swallowing problems (dysphagia) are also often present. The main symptoms of this disease are: Slurred and slow speech, Inability to speak louder than a whisper or speaking too loudly, fast speech that is difficult to understand raspy or strained voice, uneven or abnormal speech rhythm, Uneven speech volume, Monotone speech, Difficulty moving your tongue or facial muscles.
The aetiology is damage or disease of the brain and so it is most common with advancing age. Disease is usually vascular, neoplastic or degenerative. Around 85% of cases arise from strokes and around a third of people who have strokes will have dysphasia. In younger people it is usually a result of head injury.