Aphasia: loss or impairment of the power to use or comprehend words. (Koch, 15) "Language" disorder. Includes speech disorders. Usually caused by damage to the “left temporal lobe,”  “left parietal lobe,” or “left frontal lobe.” (Goldberg, 26) Commonly accompanied by difficulties in reading and writing. (OxfordMed) This condition is caused by diseases which affect the language areas of the dominant hemisphere. Clinical features are used to classify the various subtypes of this condition. General categories include ‘receptive,’  ‘expressive,’ and ‘mixed’ forms of aphasia. (MeSH)

Anomia: a particular form of aphasia which results in the loss of the use of words. Early indicator of "Alzheimer’s disease." Usually caused by damage to the left hemisphere. (Goldberg, 29) The patient is unable to recall the names of everyday objects. (Oxford) A language dysfunction characterized by the inability to name people and objects that are correctly perceived. The individual is able to describe the object in question, but cannot provide the name. This condition is associated with lesions of the dominant “hemisphere” involving the language areas, in particular the “temporal lobe.” (NCIt)

Broca’s Aphasia: difficulty in producing language. (OxfordMed) Difficulty with “grammar,” more specifically the deep structure of language. (RamachandranTTB, 295) An aphasia characterized by impairment of expressive language (speech, writing, signs) and relative preservation of receptive language abilities (i.e., comprehension). This condition is caused by “lesions” in the frontal lobe (“Broca's area” and adjacent cortical regions). The deficits range from almost complete muteness to a reduction in the fluency and rate of speech. (NCIt) Also referred to as ‘expressive aphasia,’ and ‘motor aphasia.’

Wernicke’s Aphasia: difficulty with the comprehension of the spoken word. (OxfordMed) Difficulty with comprehension and expression of meaning. (RamachandranTTB, 295) Impairment in the comprehension of speech and meaning of words, both spoken and written, and of the meanings conveyed by their grammatical relationships in sentences. It is caused by lesions that primarily affect "Wernicke's area." (PubMedHealth) Also referred to as ‘receptive aphasia,’ and ‘sensory aphasia.’