Aphasia

AUTHOR: Joseph S. Kass, MD, JD, FAAN

Definition

Aphasia is an acquired disorder of language resulting from brain damage to the dominant (typically left) hemisphere. Brain lesions causing aphasia are illustrated in Fig. E1. The damage may be vascular, traumatic, neurodegenerative, neoplastic, infectious, or inflammatory. Stroke is by far the most common cause of aphasia.
Aphasia is not the same as dysarthria (a disorder of the neuromuscular control of speech) dysphonia (a disorder of the voice), apraxia of speech (disorder of programming of articulation of sequences of phonemes, especially consonants), aphemia (muteness with normal reading, writing, and comprehension), or stuttering.
Language has a specific neuroanatomy, and aphasia manifests differently depending on the part of the language system that is damaged. Fig. E2 depicts most of the major nodes of the language system. Fig. E3 is a schematic of how the brain processes and produces language.

Figure E1 (A) Lesions Causing Nonfluent Aphasia are Typically Located in the Frontal Lobe and Encompass Broca Area and the Adjacent Cortex Motor Strip

(B) Those Causing Fluent Aphasia are in the Temporoparietal Region. Neurodegenerative Illnesses Also May Damage Wernicke Areas and More Posterior Regions and Cause Fluent Aphasia. (C) Lesions Causing Conduction Aphasia, Which are Relatively Small, Interrupt the Arcuate Fasciculus in the Parietal or Posterior Temporal Lobe. (D) Those Causing Mixed Transcortical (Isolation) Aphasia Involve the Watershed Region, Which Encircles the Perisylvian Language Arc.

From Kaufman DM et al: Kaufman’s clinical neurology for psychiatrists, ed 9, Philadelphia, 2023, Elsevier.

Figure E2 The Lateral Surface of the Left Hemisphere, Showing a Simplified Gyral Anatomy and the Relationships Between Wernicke Area and Broca Area

Not Shown is the Arcuate Fasciculus, Which Connects the Two Cortical Speech Centers by the Deep, Subcortical White Matter.

From Jankovic J et al: Bradley and Daroff’s neurology in clinical practice, ed 8, Philadelphia, 2022, Elsevier.

Figure E3 Coronal Plane Diagram of the Brain, Indicating the Inflow of Auditory Information from the Ears to the Primary Auditory Cortex in Both Superior Temporal Regions (xxx) and Then to the Wernicke Area (Ooo) in the Left Superior Temporal Gyrus

The Motor Outflow of Speech Descends from the Broca Area (B) to the Cranial Nerve Nuclei of the Brain Stem by the Corticobulbar Tract (Dashed Arrow). Actually, the Broca Area is Anterior to the Wernicke Area, and the Two Areas Would Not Appear in the Same Coronal Section.

From Jankovic J et al: Bradley and Daroff’s neurology in clinical practice, ed 8, Philadelphia, 2022, Elsevier.

Synonyms

Aphasia conductive
Aphasia, expressive (difficulty speaking)
Aphasia, expressive and receptive
Aphasia, receptive
Aphasia-angular gyrus syndrome
Conduction aphasia
Expressive dysphasia
Global aphasia
Psycho-sensory aphasia

ICD-10 CM CODES
R47.01		Aphasia
I69.320		Aphasia following cerebral infarction
I69.020		Aphasia following nontraumatic subarachnoid hemorrhage
I69.120		Aphasia following nontraumatic intracerebral hemorrhage
I69.920		Aphasia following unspecified cerebrovascular disease

Epidemiology & Demographics

Prevalence

The United States has >1 million survivors of stroke-related aphasia. Aphasia is common after acute stroke, with 21% to 38% of stroke patients experiencing aphasia and almost 80% still experiencing aphasia at 12 mo after the stroke.

Diagnosis ⬆ ⬇

Although aphasia can arise from any acquired damage to the language network, stroke-related aphasia is the most common cause.
Box 1 summarizes the clinical evaluation of a patient with aphasia. Salient features of nonfluent (Table 1) and fluent (Table 2) are described in Table 3.
The presence of aphasia may be obvious when listening to a patient’s spontaneous speech but can be mistaken for or coexist with encephalopathy or delirium, making the diagnosis more difficult in the acute setting.
Stroke-related aphasia will arise suddenly and will have associated neurologic signs and symptoms referable to the affected vascular territory, typically the territory of the left middle cerebral artery or its branches or even more severely, the left internal carotid artery.
When an acute cerebrovascular event is suspected, the history, physical examination, evaluation, and treatment are all geared to determining the underlying cause of the acute change and implementing appropriate therapies in a timely manner.
Once a patient with acute onset of aphasia is stabilized, evaluated, and treated with time-sensitive interventions, a more thorough examination of the patient’s language deficit may be undertaken. This same approach to the bedside evaluation of aphasia applies to patients presenting with subacute and chronic language complaints. This evaluation allows for localization of the aphasia and the generation of an appropriate differential diagnosis (Table 4).
The history should include questions about the time of onset (acute vs. insidious), the duration and tempo of symptom progression (acute change, rapid deterioration, or slowly progressive), accompanying constitutional, autonomic (e.g., orthostasis, bowel or bladder incontinence), neurologic (e.g., focal weakness or numbness, falls, Parkinsonism, seizures), and neuropsychiatric (e.g., apathy, disinhibition, lack of empathy, aggression, depression, visual or auditory hallucinations, delusions, changes in sleep, acting out of dreams) symptoms.
In addition to performing a neurologic examination, the patient presenting with a language complaint should undergo a thorough assessment of language function as well as cognitive screening. Language assessment begins with an analysis of a patient’s fluency and speech content, most easily achieved by listening to a patient’s spontaneous speech during the interview or by asking open-ended questions. Other critical elements of the bedside language examination include assessing comprehension (asking the patient to follow increasingly complex commands or to interpret the meaning of sentences with complex syntax), naming (of both common and uncommon objects), reading (regular and irregular words aloud as well as assessing reading comprehension), writing (spontaneously, to dictation, and copying), and repetition (of both simple and grammatically complex phrases).

TABLE 4 Principal Aphasia Syndromes Due to Stroke

Type	Lesion Site	Fluency	Comprehension	Repetition	Naming	Other Signs
Broca (expressive)	Inferior frontal lobe	↓	Good	↓	↓	Contralateral weakness
Wernicke (receptive)	Posterior superior temporal lobe	Good	↓	↓	↓	Homonymous hemianopia
Transcortical motor	Inferior frontal gyrus	↓	Good	Good	May be normal	May be contralateral weakness
Transcortical sensory	Middle temporal gyrus, thalamus	Good	↓	Good	Usually normal	May be normal
Conduction	Supramarginal gyrus	Good	Good	↓	↓	None
Global	Frontal lobe (large)	↓	↓	↓	↓	Hemiplegia

↓, Reduced.

From Wing EJ, Schiffman FJ: Cecil essentials of medicine, ed 10, Philadelphia, 2022, Elsevier.

TABLE 1 Nonfluent Aphasias

	Comprehension	Repetition
Broca’s	Intact	Lost
Transcortical motor	Intact	Intact
Mixed transcortical	Lost (isolation)	Intact
Global	Lost	Lost

From Kaufman DM et al: Kaufman’s clinical neurology for psychiatrists, ed 9, Philadelphia, 2023, Elsevier.

TABLE 2 Fluent Aphasias

	Comprehension	Repetition
Wernicke’s	Lost	Lost
Transcortical sensory	Lost	Intact
Conduction	Intact	Lost
Anomic	Intact	Intact

From Kaufman DM et al: Kaufman’s clinical neurology for psychiatrists, ed 9, Philadelphia, 2023, Elsevier.

TABLE 3 Salient Features of the Nonfluent and Fluent Aphasias

Feature	Nonfluent	Fluent
Other terms	Expressive Motor Brocass	Receptive Sensory Wernickeee
Spontaneous speech
Content	Paucity of words, mostly nouns and verbs	Complete sentences with normal syntax
Articulation	Dysarthric, slow, stuttering	Good
Errors	Telegraphic speech	Paraphasic errors, circumlocutions, tangentialities, clang associations
Associated deficits	Right hemiparesis (arm, face, leg)	Hemianopsia, hemisensory loss
Localization of lesion	Frontal lobe	Temporal or parietal lobe Occasionally diffuse

From Kaufman DM et al: Kaufman’s clinical neurology for psychiatrists, ed 9, Philadelphia, 2023, Elsevier.

BOX 1 Clinical Evaluation for Aphasia

Spontaneous speech: Fluent versus nonfluent

Verbal tests
- Comprehension
  - Ability to follow simple requests, e.g., “Please, pick up your hand”
  - Ability to follow complex requests, e.g., “Please, show me your left ring finger, and stick out your tongue”
- Naming
  - Common objects: Tie, keys, pen
  - Uncommon objects: Watchband, belt buckle
- Repetition
  - Simple phrases: e.g., “The boy went to the store”
  - Complex phrases: e.g., “No if's, and's, or but's”
  - Reading and writing tests

From Kaufman DM et al: Kaufman’s clinical neurology for psychiatrists, ed 9, Philadelphia, 2023, Elsevier.

Differential Diagnosis

Neurodegenerative Causes of Aphasia

Language function is among the cognitive domains affected by Alzheimer disease (AD) even in early clinical stages. Patients develop difficulty understanding others, will sometimes use the incorrect word, and will have trouble getting words out and finding the correct word.
Primary progressive aphasias (PPAs) are a group of neurodegenerative disorders in which an aspect of the language network is the primary target of degeneration. The PPAs include nonfluent/agrammatic variant of PPA (nfvPPA) and the semantic variant of PPA (svPPA), both classified under the umbrella of frontotemporal lobar degeneration (FTLD), as well as logopenic progressive aphasia (lvPPA), an atypical variant of AD pathology. Table 5 outlines the clinical features and localization.
In nfvPPA, patients present with nonfluent, agrammatic speech, with some also experiencing apraxia of speech. Degeneration of the left posterior frontoinsular association cortex is the cause of this language-based dementia.
In svPPA, patients develop difficulty naming, loss of object knowledge, and surface dyslexia (the inability to read irregular words properly) typically to the result of left anterior temporal lobe degeneration. However, this variant can begin in the right anterior temporal lobe, causing difficulty recognizing faces and meaning of facial expressions, before spreading to the left anterior temporal lobe and causing semantic language dysfunction.
In lvPPA, patients have impaired naming and sentence repetition, develop long pauses in their speech, and experience phonologic errors in their speech. This variant arises from left posterior perisylvian or parietal association cortex degeneration.

TABLE 5 Clinical Characteristics of Primary Progressive Aphasia

	Clinical Features ∗	Cortical Atrophy	Pathologic Changes ^†	Alternative Nomenclature
Nonfluent/agrammatic PPA	Grammatical simplification and errors in language production Effortful, halting speech with speech sound errors Two or more of the following: Impaired syntactic comprehension, spared content word comprehension, or spared object knowledge	Left inferior frontal and insula	FTLD-tau (52%), AD (25%), FTLD-TDP (19%), and other (4%)	Progressive nonfluent aphasia (PNFA) Agrammatic PPA (PPA-G)
Semantic variant PPA	Poor confrontation naming Impaired single-word comprehension Three or more of the following: Poor object or person knowledge or both; surface dyslexia; spared repetition; or spared motor speech	Anterior and ventral temporal lobe	FTLD-TDP (69%), AD (25%), and FTLD-tau (6%)	Semantic dementia (SD) Semantic PPA (PPA-S)
Logopenic variant PPA	Impaired single-word retrieval Impaired repetition of phrases and sentences Three or more of the following: Speech sound errors, spared motor speech, spared single-word comprehension and object knowledge, or absence of agrammatism	Left posterior superior temporal and inferior parietal	AD (50%), FTLD-TDP (38%), and FTLD-tau (12%)	Logopenic progressive aphasia (LPA) Logopenic PPA (PPA-L) Progressive mixed aphasia (PMA)

AD, Alzheimer disease; FTLD-tau, frontotemporal lobar degeneration with tau-positive pathology; FTLD-TDP, frontotemporal lobar degeneration with ubiquitin-positive and TDP-43-positive pathology; PPA, primary progressive aphasia.

^∗Based on expert consensus.

^†From a literature review of confirmed pathologic changes in patients with PPA recruited without a-priori bias.

Reprinted with permission from Elsevier. From Grossman M: The non-fluent/agrammatic variant of primary progressive aphasia, Lancet Neurol 11(6):545-555, 2012. https://doi.org/10.1016/s1474-4422(12)70099-6.

Workup

Targeted to the underlying etiology of the aphasia but will always include neuroimaging, preferably MRI of the brain.
In nonstroke aphasia and in patients without significant kidney disease, MRI should be done with and without contrast.
In stroke-related aphasia, acute neuroimaging will include a brain computed tomography (CT) and CT angiogram of the head and neck. An MRI can be performed after acute interventions have been performed.
Advanced neuroimaging techniques such as fluorodeoxyglucose (FDG)-PET may be appropriate for neurodegenerative aphasias.

Laboratory Tests

Targeted to the underlying etiology of the aphasia. In stroke-related aphasia, the laboratory workup will include an assessment of vascular risk factors. In a neurodegenerative aphasia, the assessment will be similar to that for AD.

Treatment ⬆ ⬇

Nonpharmacologic Therapy

Speech language therapy. Commonly used techniques include script training, response elaboration training, constraint-induced aphasia therapy, speech entrainment, and melodic intonation therapy.

Acute General Rx

Target the underlying cause of the aphasia

Chronic Rx

Target the underlying cause of aphasia and include speech language therapy.

Referral

Neurology
Speech language pathology
Neuropsychology
Physical medicine and rehabilitation
Psychiatry

Pearls & Considerations ⬆ ⬇

Comments

Recovery from poststroke aphasia is very difficult to predict. The most important factors correlating with recovery are the lesion location and size, aphasia type and severity, and to some extent the nature of early hemodynamic response to acute interventions such as thrombolysis, and treatment received.
Most studies attest that recovery is inversely related to the size of lesion, with a preserved left superior temporal gyrus as one of the most important factors for satisfactory recovery and intact basal ganglia also contributing significantly to better recovery.
Broca and conduction aphasia enjoy better recovery than global and anomic aphasia.

Prevention

Prevention of stroke-related aphasia involves modification of vascular risk factors.

Patient/Family Education

Teach families of aphasia patients about supportive communication strategies (Table 6)

BOX 2 Stimulation-Facilitation Approaches for Aphasia Therapy

Gestural expression and pointing
Word-to-picture matching
Yes/no response reliability
Oral-motor imitation
Phoneme, then word repetition
Verbal cueing for words and sentence completion
Contextual cueing
Phonemic and semantic word-retrieval strategies
Priming for responses
Auditory processing at phrase level and then sentence level
Word-, phrase-, then sentence-level reading
Melodic stimulation
Graphic tasks: Tracing, copying, word completions
Calculations
Pragmatic linguistic and nonlinguistic conversational skills
Psychosocial supports

From Jankovic J et al: Bradley and Daroff’s neurology in clinical practice, ed 8, Philadelphia, 2022, Elsevier.

TABLE 6 Supportive Communication Strategies for Aphasia

Verbal Strategies	Environmental Strategies	Visual Strategies
Speak slowly but with a natural tone and rhythm Use short, simple sentences Gently give two or three options when providing choices Ask yes or no questions Use writing, gestures, or drawing in addition to speaking Give the person more time to speak Repeat your question or instructions if the person asks or seems unsure Repeat what the person says to make sure you understood correctly Ignore simple mistakes that do not change the meaning of the message (do not correct the person)	Remove distractions (e.g., turn off the TV, close the door) Adjust lighting so the person can see you easily Sit or stand facing the person when speaking or listening to the person; make eye contact Keep communication tools nearby (e.g., pen/paper, communication book, picture) Limit group conversations to only a few people	Use direct eye contact Use gestures to enhance your message (e.g., thumbs up/down) Write important words you are saying to help the person understand Write notes when communication breakdown occurs and return to them later Point to objects/pictures as you talk to give the person a visual of what you are saying If written information is being provided, leave extra white space on the paper, use short sentences, and use simple language

From Armour M et al: Supportive communication for individuals with aphasia, Arch Phys Med Rehabil 102(7);1437-1439, 2021. https://doi.org/10.1016/j.apmr.2021.03.008.

Related Content

Stroke, Ischemic (Related key Topic)

Alzheimer Disease (Related key Topic)

Frontotemporal Dementia (Related key Topic)

section name header

Basic Information ⬇

Diagnosis ⬆ ⬇

Treatment ⬆ ⬇

Pearls & Considerations ⬆ ⬇

Suggested Readings ⬆