Receptive aphasia, also known as Wernicke's aphasia, is a subclass of fluent aphasias in which individuals have difficulty understanding written and spoken language because of damage to a distributed network of brain regions involved in language comprehension rather than a single isolated area. Patients with Wernicke's aphasia often have fluent speech, which is characterized by typical speech rate and effortless speech output, but the content may lack meaning or include incorrect or made-up words. Writing often reflects speech by lacking substantive content or meaning, and may contain paraphasias or neologisms, similar to how spoken language is affected. In most cases, motor deficits (i.e., hemiparesis) do not occur in individuals with Wernicke's aphasia. Therefore, they may produce a large amount of speech without much meaning. Individuals with Wernicke's aphasia commonly show anosognosia, meaning they may be unaware of their errors in speech and may not realize that their spoken language lacks meaning. They typically remain unaware of even their most profound language deficits.

Like many acquired language disorders, Wernicke's aphasia can be experienced in many different ways and to many different degrees. Patients diagnosed with Wernicke's aphasia can show severe language comprehension deficits; however, this is dependent on the severity and extent of the lesion. Severity levels may range from being unable to understand even the simplest spoken and/or written information to missing minor details of a conversation.

Wernicke's aphasia was named after German physician Carl Wernicke, who is credited with discovering the area of the brain responsible for language comprehension (Wernicke's area) and discovery of the condition which results from a lesion to this brain area (Wernicke's aphasia).

Signs and symptoms

People with Wernicke's aphasia often produce fluent but disorganized speech that may include made-up words (neologisms) or incorrect word substitutions (semantic paraphasias). Although their speech sounds fluent, it can be difficult to follow because the content lacks meaning.

The following are common symptoms seen in patients with Wernicke's aphasia:

  • Impaired comprehension: deficits in understanding (receptive) written and spoken language. In some patients this type of anomia is specific to certain categories like colors or animals.
  • Semantic anomia: unlike patients with word-selection anomia, patients exhibiting semantic anomia also lose the ability to correctly distinguish the function or use of a given object, along with not being able to provide the name of it. Therefore, even provided with both the name and function of an object, these patients still would not be able to correctly select it out of a group.
  • Neologisms: Neologism is a Greek-derived word meaning "new word". The term is used in this sense to mean invented non-words that have no relation to the target word, Jargon can consist of a string of neologisms, as well as a combination of real words that do not make sense together in context. The jargon may include word salads.
  • Fluent speech: individuals with Wernicke's aphasia do not have difficulty with producing connected speech that flows. Although the connection of the words may be appropriate, the words they are using may not belong together or make sense (Jargon). For example, a person might answer a simple question with a fluent but confusing sentence such as, "The dog of my chair went glimmering", illustrating intact speech flow but reduced meaningful content. Some patients with Wernicke's aphasia experience logorrhea, which is also known as over fluency. These patients use an excessive amount of words when speaking or writing.
  • Awareness: Individuals with Wernicke's aphasia are often not aware of their incorrect productions, which would further explain why they do not correct themselves when they produce jargon, paraphasias, or neologisms. Additionally, patients may become irritated or frustrated because others cannot understand what they are saying, but they believe their speech is completely comprehensible.
  • Paraphasias:
  • Phonemic (literal) paraphasia: Errors in selecting phonemes. Involves the substitution, addition, omission, or rearrangement of sounds so that an error can be defined as sounding like the target word. Often, half of the word is still intact which allows for easy comparison to the appropriate, original word (such as "bap" for "map"). The more phonemic paraphasias in a word, the harder it is to understand, to the extent at which may become unidentifiable. Often, these unidentifiable words are known as neologisms.
  • Semantic (verbal) paraphasia: Failure to select the proper words with which to convey their ideas. The word used is always a real word, however it may not always be directly or closely related to the word the patient is trying to convey. Can result in saying a word that is related to the target word in meaning or category (for example, "jet" for "helicopter", or "knife" for "fork"). Other times, semantic paraphasias can result in empty speech, or the use of overly generic words such as "thing" or "stuff" to stand in for the word they cannot come up with. This leads to speech that contains real words but lacks any substantial meaning.
  • Circumlocution: talking around the target word,
  • Global aphasia: individuals have extreme difficulties with both expressive (producing language) and receptive (understanding language).
  • Anomic aphasia: the biggest hallmark is one's poor word-finding abilities; one's speech is fluent and appropriate, but full of circumlocutions (evident in both writing and speech).
  • Conduction aphasia: individuals can comprehend what is being said and are fluent in spontaneous speech, but they cannot repeat what is being said to them.
  • Transcortical sensory aphasia: individuals have impaired auditory comprehension with intact repetition and fluent speech.
  • Progressive confluent aphasia: A form of frontotemporal dementia characterized by motor speech impairment, agrammatism, laborious speech, and apraxia of speech. It is understood that comprehension of speech and semantic memory are relatively preserved. Symptoms progress over time unlike many other aphasias where symptoms appear immediately after stroke.
  • Wernicke–Korsakoff syndrome: A well-described syndrome of neurological and cognitive problems that comprises both Wernicke's Encephalopathy (WE) and Korsakoff Syndrome (KS). It is often characterized by impairment in memory formation and is caused by long term thiamine deficiency.

Causes

The most common cause of Wernicke's aphasia is stroke. Strokes may occur when blood flow to the brain is completely interrupted or severely reduced. This has a direct effect on the amount of oxygen and nutrients being able to supply the brain, which causes brain cells to die within minutes. The most common stroke that causes Wernicke's aphasia is an ischemic stroke affecting the posterior temporal lobe of the dominant hemisphere of the brain. Therefore, in patients with Wernicke's aphasia, there is typically an occlusion to the left middle cerebral artery. Other causes of Wernicke's aphasia include brain trauma, cerebral tumors, central nervous system (CNS) infections, and degenerative brain disorders. In circumstances where a person is showing possible signs of aphasia, the physician will refer him or her to a speech–language pathologist (SLP) for a comprehensive speech and language evaluation. SLPs will examine the individual's ability to express him or herself through speech, understand language in written and spoken forms, write independently, and perform socially.

Formal assessments include:

  • Boston Diagnostic Aphasia Examination (BDAE): diagnoses the presence and type of aphasia, focusing on location of lesion and the underlying linguistic processes.  
  • Western Aphasia Battery – Revised (WAB): determines the presence, severity, and type of aphasia; and can also determine baseline abilities of patient.
  • Communication Activities of Daily Living – Second Edition (CADL-2): measures functional communication abilities; focuses on reading, writing, social interactions, and varying levels of communication.
  • Revised Token Test (RTT): assess receptive language and auditory comprehension; focuses on patient's ability to follow directions.

Informal assessments, which aid in the diagnosis of patients with suspected aphasia, include:

  • Conversational speech and language sample

According to Bates et al. (2005), "the primary goal of rehabilitation is to prevent complications, minimize impairments, and maximize function". The topics of intensity and timing of intervention are widely debated across various fields. Results are contradictory: some studies indicate better outcomes with early intervention, while other studies indicate starting therapy too early may be detrimental to the patient's recovery. Recent research suggests, that therapy be functional and focus on communication goals that are appropriate for the patient's individual lifestyle.

Specific treatment considerations for working with individuals with Wernicke's aphasia (or those who exhibit deficits in auditory comprehension) include using familiar materials, using shorter and slower utterances when speaking, giving direct instructions, and using repetition as needed. Neuronal changes after damage to the brain such as collateral sprouting, increased activation of the homologous areas, and map extension demonstrate the brain's neuroplastic abilities. According to Thomson, "Portions of the right hemisphere, extended left brain sites, or both have been shown to be recruited to perform language functions after brain damage. All of the neuronal changes recruit areas not originally or directly responsible for large portions of linguistic processing. Principles of neuroplasticity have been proven effective in neurorehabilitation after damage to the brain. These principles include: incorporating multiple modalities into treatment to create stronger neural connections, using stimuli that evoke positive emotion, linking concepts with simultaneous and related presentations, and finding the appropriate intensity and duration of treatment for each individual patient.

Restorative therapy approach

Neuroplasticity is a central component to restorative therapy to compensate for brain damage. This approach is especially useful in Wernicke's aphasia patients that have had a stroke to the left brain hemisphere.

Schuell's stimulation approach is a main method in traditional aphasia therapy that follows principles to retrieve function in the auditory modality of language and influence surrounding regions through stimulation. The guidelines to have the most effective stimulation are as follows:

Auditory stimulation of language should be intensive and always present when other language modalities are stimulated.

  • Conversational coaching involves patients with aphasia and their speech language pathologists, who serve as a "coach" discussing strategies to approach various communicative scenarios. The "coach" will help the patient develop a script for a scenario (such as ordering food at a restaurant), and help the patient practice and perform the scenario in and out of the clinic while evaluating the outcome.
  • Supported conversation also involves using a communicative partner who supports the patient's learning by providing contextual cues, slowing their own rate of speech, and increasing their message's redundancy to promote the patient's comprehension. The quicker a diagnosis of a stroke is made by a medical team, the more positive the patient's recovery may be. A medical team will work to control the signs and symptoms of the stroke and rehabilitation therapy will begin to manage and recover lost skills. The rehabilitation team may consist of a certified speech–language pathologist, physical therapist, occupational therapist, and the family or caregivers.