Transcortical motor aphasia (also known as Anterior Isolation Syndrome) is caused by damage to the cortical areas of language around Broca's area, often deep into the white matter of the supplementary speech area. Damage can commonly occur when people have strokes (30% of stroke victims display some form of aphasia), head trauma, infection or brain tumor.

Symptoms vary from partial to total loss of ability to communicate. Patients will display little or no desire to communicate, although their comprehension of events and language is good. One patient who recovered from this condition described having 'nothing to say' and their 'mind felt empty'. When people spoke to them they understood, but had no interest in replying. When patients do speak, they reply in very short, one or two word, sentences. With encouragement they are able to repeat long and complex sentences, but not without strong urging.

Diagnosis - Following a stroke or head injury aphasia should always be tested for. This can take the form of face to face language evaluation by the doctor, asking a patient to name items, describe them, display understanding and demonstrate written skills. Should any of these areas cause concern, more specific aphasia tests and brain scans can help locate the exact area of damage.

Treatment - there are no drugs available to treat aphasia. Speech therapy is recommended as soon as possible, following diagnosis, as the best chance for recovery occurs in the first three months following onset. Speech therapy will try to strengthen remaining skills, or find ways to compensate for lost abilities.