Aphasia

Aphasia ^{[75, 185, 198, 221]} is a term of Greek origin meaning "loss of speech" ^[222]. It refers to a partial or total acquired loss of the ability to express and/or understand language, whether spoken or written, despite the anatomical and functional integrity of the phonatory organs (tongue, larynx) and independent of any neurological impairment of sensory origin (without hearing or visual difficulties) or motor origin (primary motor cortex) ^[185].

Pathophysiology :

Aphasia occurs following a lesion of the dominant left hemisphere for language. This lesion appears as a result of brain injury: a tumor, head trauma, or most commonly, a stroke (CVA) ^[198].

Most people with aphasia do not completely lose the use of speech. Aphasia is a language disorder that can present significant nuances: some patients show only slight hesitation in finding their words, while others have almost entirely lost the ability to express themselves, understand what is being said to them, read, and/or write, even while other faculties such as memory or orientation remain well-preserved.

Classification :

There are several types of aphasia, depending on the underlying mechanisms and the clinical manifestation of the cerebral abnormalities ^[50]. Classically, aphasia can be classified into three main categories ^[212]:

Sensory aphasia, or Wernicke's aphasia:

This type of aphasia is characterized by a deficit in language comprehension and difficulty interpreting the meaning of words and sentences ^{[5, 198]}. It is characterized by severe comprehension impairment and by verbal expression using inappropriate words, including the use of new vocabulary (neologisms ^[50]).

The patient is often unaware of their impairment ^[223]. This type of aphasia primarily occurs during a lesion in the left hemisphere affecting Wernicke's area.

Motor aphasia or Broca's aphasia:

Loss of speech, difficulty expressing ideas ^[49]. It is characterized by oral and written impairments, whereas comprehension remains relatively good. The patient generally exhibits various degrees of articulation problems and uses non-structured sentences. They have difficulty finding the exact words to express themselves, and the words used are often inappropriate. This type of aphasia is generally seen during a right hemiplegia (paralysis affecting the right half of the body) in which Broca's area is affected.

Conduction aphasia:

This type of aphasia ^[198] often occurs during a lesion involving the arcuate fasciculus ^[221], which connects Wernicke's area to Broca's area. Conduction aphasia is characterized by difficulties in both the expression and reception of language. The management of this type of aphasia is often very difficult, especially when the impairments are severe.