Q 1.16. Higher Cortical Functions: Speech and Aphasia. Alexia, agraphia.

1. Aphasia:

   • Aphasia is a language disorder resulting from damage to specific brain areas responsible for communication.
   • Most commonly, these areas are located in the left hemisphere of the brain.
   • Aphasia can occur suddenly after a stroke or head injury, or it may develop gradually due to brain tumors or progressive neurological diseases.
   • It impairs language expression, comprehension, reading, and writing.
   • People with aphasia often experience other language-related issues, such as difficulty speaking correctly or understanding speech.

2. Types of Aphasia:

   • Wernicke’s Aphasia:
     • Results from damage to the temporal lobe.
     • Individuals with Wernicke’s aphasia speak in long, nonsensical sentences, often adding unnecessary words or creating made-up terms.
     • They struggle to convey coherent meaning, and their comprehension of speech is impaired.
   • Broca’s Aphasia:
     • Caused by damage to the frontal lobe.
     • People with Broca’s aphasia understand speech and know what they want to say, but they produce short, effortful phrases.
     • Right-sided weakness or paralysis of the arm and leg may accompany this type due to frontal lobe involvement.

Alexia: Word Blindness

• Alexia refers to the loss of the ability to recognize words that one could previously read.
• It results from damage to language processing centers in the brain.
• People with alexia experience difficulty understanding written words, even though their spoken language remains intact.
• Essentially, they become “word blind.”

Agraphia: Loss of Writing Ability

• Agraphia is the inability to write properly due to brain damage.
• Writing involves multiple skills, including language processing, choosing the right letters, planning how to form them, and physically copying them.
• Damage to any part of this process can lead to agraphia.
• People with agraphia often have other language impairments, such as difficulty reading or speaking correctly.

In summary, understanding these higher cortical functions is crucial for medical students, as they provide insights into brain function, language processing, and communication disorders.

References:

(1)ncbi.nlm.nih.gov