Let’s talk about aphasia


Imagine life without language. For people living with aphasia, that’s their reality. Aphasia, which is caused by damage in the language centers of the brain, affects the ability to speak, understand speech, and read or write. There are currently 1 million Americans with aphasia; 80,000 new cases occur in the U.S. every year. As stroke is the leading cause of aphasia, the American Stroke Association designates June as National Aphasia Awareness Month to increase access to information and support for aphasia patients.

What causes aphasia?

Aphasia occurs when blockage or rupture of a blood vessel cuts off blood supply to the language centers located in the brain’s left hemisphere. Without oxygen and nutrients, the neurons die. Neuronal death and missing neural connections result in impaired language abilities. Head injuries, tumors and degenerative diseases also can cause aphasia by damaging the left hemisphere.

What are the types of aphasia?

Broca’s aphasia affects the ability to fluently speak in grammatically accurate sentences. Comprehension may be mildly impaired. People with Wernicke’s aphasia can construct sentences, albeit with meaningless or empty words. They also have difficulty comprehending spoken language. Global aphasia affects both speech and comprehension.

Most aphasia patients retain good memory, attention and perception. “A lot of them improve with targeted speech therapy,” says Yasmeen Faroqi-Shah at the University of Maryland. She adds, “An important question is how the brain recovers after a stroke or injury.” Some studies show that the undamaged parts of the left hemisphere take over language function. This ability of the brain to regain function by forming new neural connections is called neural plasticity. The formation of new connections is controlled tightly by positive and negative regulators. For example, growth-associated protein 43 helps form cellular projections called neurites that connect one neuron with others. Neurite outgrowth inhibitor A, or Nogo-A, inhibits neural connectivity by blocking neurite outgrowth.

Are there biochemical interventions available to improve recovery?

Pharmacological agents, when used along with speech therapy, can improve language recovery in aphasia patients. Piracetam, a γ-aminobutyric acid derivative, is a drug that acts on neurotransmitters like acetylcholine and glutamate. Patients using piracetam have improved comprehension, reading and writing because the drug stimulates cholinergic and glutamatergic neurotransmitter systems. Preclinical studies indicate that administering an anti-Nogo-A antibody or transplanting stem cells at the site of damage to replace dying neurons can boost neural plasticity and help in recovery.

Indumathi Sridharan Indumathi Sridharan earned her bachelor’s degree in bioinformatics in India. She holds a Ph.D. in molecular biochemistry from Illinois Institute of Technology, Chicago. She did her postdoctoral work in bionanotechnology at Northwestern University.