Aphasia

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Original Editor - Cindy John-Chu

Top Contributors - Cindy John-Chu, Niha Mulla, Shaimaa Eldib, Kim Jackson, Candace Goh, Rucha Gadgil, Chelsea Mclene and Pacifique Dusabeyezu  

Definition

Aphasia is a condition, where a person has difficulty with their language or speech which is most commonly caused by damage to the left side of the brain for example, after a stroke, head injury or brain tumor.

Introduction

As mentioned above aphasia is a condition resulting from damage to areas of the brain responsible for language, which for most people is located in the left hemisphere of the brain. The condition presents as an impairment to comprehension or formulation of language and is often caused by diseases and disorders affecting the brain, with cerebrovascular accident being the most common cause.

Anatomy

Areas of the brain responsible for language:

• Werncike's area
• Broca's area
• Arcuate fasciculus

The Wernicke's area is located in the temporal lobe and is responsible for processing visual and auditory information. It is the center for comprehension and planning of words. Broca's area on the other hand is located in the frontal lobe of the brain. It is responsible for motor execution of speech and sentence formation. While the arcuate fasciculus is the neural connection between both areas.

Causes of aphasia

Aphasia can occur from a number of brain injuries and conditions such as:

• Stroke
• Traumatic brain injury
• Severe blows to the head
• Brain tumors
• Gunshot wounds
• Brain infections
• Alzheimer's disease
• Frontotemporal lobar degeneration
• Vascular dementia
• Pick disease

Types of Aphasia

Aphasia can be broadly classified as either fluent or non-fluent.

1. Non-Fluent aphasia includes:
   • Broca's
   • Transcortical motor
   • Mixed transcortical
   • Global
2. Fluent aphasia types are:
   • Wernicke's
   • Transcortical sensory
   • Conduction
   • Anomic

The most common types of aphasia include:

• Broca's aphasia.
  • Occurs from damage to the frontal lobe.
  • Patients may understand what is being said them, know what response to give but may often reply with short phrases with so much effort.
  • Patients may become frustrated from their difficulty in communicating clearly making some sliding into depression.
  • May often present with right hemiparesis/hemiplegia as the frontal lobe is also important for motor movements.
  • Also referred to as expressive aphasia.
• Wernicke's aphasia
  • Occurs from damage to Brodmann area 22 of the temporal lobe also known as Wernicke's area
  • Is characterised by patients composing and speaking long, complete sentences that have no meaning. They may even formulate non-existent new words to express themselves.
  • They experience difficulty in understanding speech.
  • These patients are often unaware of their speaking blunders.
  • It is also known as receptive aphasia.
• Global Aphasia
  • May have trouble understanding simple words and sentences.
  • May be limited in their ability to speak and comprehend language.

Other forms of aphasia are:

• Conduction Aphasia is caused by lesion located in the arcuate fasciculus. Patients with this type of aphasia experience difficulties with or are unable to repeat words spoken to them. They realise the errors they make and endeavour to correct them.
• Transcortical Sensory Aphasia is caused by lesions around but not affecting the Wernicke's area. Patients may be able to repeat speech fluently but have difficulties with comprehension.
• Transcortical Motor Aphasia is from lesions around but that do not affect the Broca's area. Patients have a tendency to remain silent and may repeat one to two words. They may also be able to repeat long complex phrases although their speech may not be fluent.
• Mixed Transcortical Aphasia results from lesions around the language areas of the brain but that do not affect them. Patients in this category have severe speaking and comprehension impairment but can repeat long, complex sentences.
• Anomia is the mildest form of aphasia and is from damage to angular gyrus. It is characterised by patients having difficulties with finding words.

Differential Diagnoses

• Dysphonia
• Dysarthria
• Cognitive communication disorder
• Altered mental status from encephalopathy

Relevance to Physiotherapy

Physiotherapists get to manage patients with neurological conditions that may and often lead to aphasia. It is important to be knowledgeable about the condition and its types to aid appropriate referral if/when detected by the physiotherapist in the course of patient care, and also to optimise interaction with patients.