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Receptive aphasia, also known as Wernicke’s aphasia, sensory aphasia or fluent aphasia, is a type of aphasia characterised by a difficulty in understanding auditory language and in producing coherent speech.

Aphasia is a language disorder that can be found in speech, reading or writing due to dysfunction of specific brain regions. Causes of aphasia include organic brain diseases, head injuries, tumours and, most commonly, strokes (thought to cause 85% of all cases of aphasia).

History
The Edwin Smith surgical papyrus dating from 3500 BC discusses a patient with language difficulties following a temporal lobe injury. However, it was not until the 19th century that Bastian (1869) and Schmidt (1871) wrote about patients suffering from difficulties with comprehension. These observations were followed by a monograph written in 1874 by Carl Wernicke describing patients who confused words, who were unable to retrieve words, who had difficulties understanding and expressing language and who were unaware of their impairments. Wernicke described this aphasia as being sensory in nature and located these difficulties to lesions of the posterior superior temporal gyrus, or Wernicke's area.

Signs and Symptoms
Receptive aphasia is associated with difficulties categorising sounds into phonemes and isolating the phonemes that create words and sentences. Individuals with receptive aphasia do not experience difficulties in producing speech, however they can understand neither their own speech nor that of others. Typical symptoms of receptive aphasia include  :


 * Speech that is correct in terms of sentence structure and articulation but with no sense to its content.
 * Problems with auditory and written comprehension, especially sentence comprehension.
 * Very fast speech.
 * Unawareness of difficulties, especially when beginning to suffer from aphasia.
 * Word salad where random words and phrases are combined, causing the content of speech to become unintelligible . This is thought to be due to the confusion of phonetic characters, for example, 'I am going to Christmas with danger who is the telephone'.
 * Paraphrasic speech (adhering to the general rules of language but with errors in terms of phonemes and words). In extreme cases speech only contains nonsense words. For example, 'momputer' could be used instead of 'computer', and in extreme cases 'garfer' could be used instead of 'car'.
 * Using neologisms ‘(e.g. loliphant for elephant)', semantic paraphrasias '(e.g. binoculars for spectacles)’ and using general words ‘(e.g. people for women)'.
 * Imprecision in speech and difficulties retrieving words e.g. the use of ‘thing’ and ‘it’
 * Paragrammatism (the use of imprecise grammar).
 * Circumlocution (the use of ambiguous or long-winded speech e.g. describing a dog as ‘an animal with four legs and a tail that barks’ rather than using the word ‘dog’ itself).
 * Complete agraphia (inability to write), although the extent to which reading and writing is affected depends on the location of brain lesions. If able to write, writing is similar to speech in terms of its structure and errors.
 * The social conventions of conversation are conserved. For example, an individual with receptive aphasia may listen to their partner in the conversation and wait their turn before speaking, despite having great difficulty in comprehending the speech of the person they are talking to.

These communication impairments cause substantial difficulties in everyday life and interaction for receptive aphasics.

===Summary of common verbal symptoms in receptive aphasia ===

Symptom Cross-over
The main presenting problems of receptive aphasia are not always as clear-cut as they first appear, which can cause difficulties. For example, aphasia itself is not the only disorder associated with aphasia-like symptoms. Similar symptoms can also be found in individuals with poor vision or hearing, impaired perception and impaired movement, thus causing difficulties in speech comprehension and production, and in conditions such as autism, dementia and schizophrenia, thus potentially causing misdiagnosis of aphasia.

A second difficulty is the difficulty placing aphasic individuals in specific categories of aphasia. This is highlighted as around 40% of aphasic patients do not fit into specific diagnostic categories for aphasia such as receptive aphasia.

Localisation
In 1965 Geschwind, like Wernicke before him, proposed that receptive aphasia was caused by a lesion in Wernicke's area, located in the posterior area of the superior temporal gyrus. However, advances in research have shown the organisation of language to be more complex than first thought and that the key difficulties of receptive aphasia are not necessarily caused by damage to Wernicke's area.

The deficits associated with receptive aphasia have been connected with damage to the language-dominant temporal lobe(the left temporal lobe for the majority of right-handed aphasics) and to areas within it which include:
 * ‘The first and posterior part of the second convolutions of the superior temporal gyrus adjacent to Heschl’s gyrus’ in the auditory association cortex.
 * The planum temporale in the left hemisphere - this is thought to be associated with memory for speech sounds and with linking the meaning of words to auditory representations.
 * The underlying white matter of the medial temporal lobe - damage here is thought to destroy local language regions and to cut off core language regions from areas of the temporal, parietal and occipital lobes.

Despite the research, the study of the neural basis of language is laden with complexity as it is likely that most of the brain has some role to play in language processes. This means that care is needed when determining the cerebral bases of receptive aphasia.