Aphasia

Aphasia is a language disorder that affects the expression or understanding of spoken or written language.

Language disability is a condition caused by a brain lesion located, in the vast majority of cases, in the left cerebral hemisphere.

These lesions can occur at any age, but they are more common in older people with stroke or dementia.

Aphasia is distinct from voice disorders ( dysphonies) and speech disorders ( dysarthrias), although people with aphasia may experience articulatory difficulties and changes in vocal volume.

Causes

A lesion of one or more areas of the brain, such as Broca’s area, the white matter, the caudate nucleus, the temporoparietal cortex, or Wernicke’s area, which can be caused by stroke, ischemic or hemorrhagic origin, head trauma, brain tumor, or dementia ( Alzheimer’s disease ).

Signs and symptoms

Despite the integrity of the tongue and larynx, the person has difficulty speaking, articulating, and understanding what is said to him.

The most characteristic symptom of aphasia is the difficulty of spontaneously finding the right word during a dialogue or in a test intended to name an object that one visualizes.

This characteristic is distinguished from non-aphasic language disorders (which are observed for example in the context of the dysexecutive syndrome) or from a confusional state.

The inability to find the correct word usually stems from a difficulty in accessing the correct phonological form. The semantic knowledge concerning the item to be named is intact.

For example, an aphasic person who cannot name the word “orange” is able to say that it is a citrus fruit, orange in color, and has no difficulty in recognizing the image of an orange. In addition, the missing word is often accompanied by an impression of having the word on the tip of the tongue and can be found by a clue (for example, the word begins with the sound « O »).

Written language is as much altered as oral language in the majority of cases.

There are mainly three forms of aphasia:

• Global aphasia: this is the most severe form of aphasia caused by complete obstruction of the middle cerebral artery; the patient speaks little or not at all. He articulates badly. Verbal communication is almost impossible.
• Wernicke’s aphasia ¹  : Wernicke’s area is the language comprehension area. The patient expresses himself, but has difficulty understanding language and making himself understood. The person cannot transpose the words read or heard into a coherent thought (verbal productions characterized by jargon or paraphasias). There is also perseveration (repeated use of the same word).
• Broca’s aphasia: Broca ‘s area is a small area on the left side of the brain (sometimes on the right in left-handed people) that is important in language processing. When damaged, an individual has difficulty speaking but can still understand speech. It works closely with Wernicke’s area (language comprehension area). Broca’s aphasia is often caused by a lesion of the left hemisphere and in particular Broca’s area. The patient has difficulty speaking and/or writing. He is unable to express himself coherently.

Wernicke’s area located in the left hemisphere.Broca’s area located in the left hemisphere.

	Fluency	Missing word	Understanding	signs
Global aphasia	very diminished	Strong inability to find the word	very altered	Speech often limited to a stereotype
Wernicke’s aphasia	Normal	Fairly strong inability to find the word	very altered	Paraphasias, dyssyntaxia, jargon
Broca’s aphasia	Diminished	Inability to find the word	Below par	Dysprosody, agrammatism

Other forms of aphasia are:

• Anomic aphasia.
• Conduction aphasia.
• Transcortical aphasia.
• Amnesic aphasia.

Diagnostic

Examination of the expression and comprehension of oral language.

Take into account the level of education and the mother tongue.

• Spontaneous language.
• Repetition of words, simple or complex, and sentences, to better identify arthritic disorders and paraphasias.
• Naming and designation of items (objects or images). The test consists of asking patients to name about ten objects presented visually, which makes it possible to detect the patient’s inability to find the word. In the event of failure, the examiner must ensure that the unnamed object has indeed been identified by the patient, by having him designate the object in multiple choice. If the patient cannot name the object because he does not identify it, this is not aphasia, but visual agnosia.
• Description of a complex image.
• Story of a story.
• Execution of simple and complex orders.
• Listening comprehension test. The examiner gives an order to the patient such as “here are 3 papers a large, a medium, a small, you will give me the large, keep the medium and throw away the small”.

Written language exam

• Identification of letters, syllables and words.
• Read aloud.
• Understanding of written language.
• Spontaneous writing.
• Dictation.

This examination can be deepened with more complex tests such as the definition of words, the interpretation of a text or the construction of a sentence with words.

Aphasia caused by stroke

It seems that fluent aphasias (Wernicke type) are more common than non-fluent aphasias with agrammatism in elderly people who have suffered a stroke.

The clinical profile can be more complex, with little difficulty in finding the word. Semantic paraphasia and visual errors can occur in patients with associated cognitive, behavioral and mood symptoms (slowing down, attention disorders, executive functions, memory disorders, depression, anxiety, apathy). Moreover, the precise evaluation of these patients is made difficult by the associated disorders and by fatigue.

Aphasia and dementia

Aphasia is present in people with different forms of dementia, partly Alzheimer’s disease  and especially  frontotemporal dementias.

Aphasia can be a symptom among others or, on the contrary, be at the forefront throughout the evolution: we then speak of primary progressive aphasia, a pathology that is part of the frontotemporal dementias.

Primary progressive aphasia usually affects people in their 60s, with an insidious onset characterized by difficulties in spontaneous speech that get progressively worse. There are two possible forms:

1. progressive nonfluent aphasia with reduced speech, articulatory difficulties, and agrammatism, while comprehension remains preserved;
2.  fluent progressive aphasia with fluent speech but difficulty understanding the word.

A particular form of primary progressive aphasia, logopenic aphasia, appears in Alzheimer’s disease.

In Alzheimer’s disease, language disorders appear discreetly and are mainly due to a lack of semantic knowledge rather than an inability to find the word.

Rehabilitation

• Recovery can occur spontaneously.
• Speech therapy sessions. They are beneficial and improve the communication capacity of patients. However, the benefit is often limited by comprehension disorders or by factors unrelated to aphasia, such as fatigue, low motivation or sensory disturbances. In most cases, the speech therapist focuses on educating the family circle, so that they communicate as well as possible with the patient. In the case of progressive aphasia, prolonged management is necessary because this form of aphasia evolves, unless the patient presents significant cognitive or comprehension disorders.