Editing Agnosia (section)

==Types==

{| class="wikitable"
! Name !! Description
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 | [[Akinetopsia]]|| Also known as cerebral akinetopsia, this is associated with the inability to see visual motion.  One cause of cerebral akinetopsia is lesions outside the [[striate cortex]].<ref>{{cite journal|last=Zeki|first=S|title=Cerebral akinetopsia (visual motion blindness)|journal=Brain|year=1991|volume=114|issue=2|pages=811–824|doi=10.1093/brain/114.2.811|pmid=2043951}}</ref>
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 | Allotopagnosia || Patients cannot point at external targets located outside their own body, whether other persons' body parts or objects, but they perfectly point at their own body parts.
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 | [[Anosognosia]] || This is the inability to gain feedback about one's own condition and can be confused with lack of [[insight]] but is caused by problems in the feedback mechanisms in the brain. It is caused by neurological damage and can occur in connection with a range of neurological impairments but is most commonly referred to in cases of paralysis following stroke. Those with anosognosia with multiple impairments may even be aware of some of their impairments but completely unable to perceive others.
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 | [[Apperceptive agnosia#Visual apperceptive agnosia|Apperceptive visual agnosia]] || Patients are unable to distinguish visual shapes and so have trouble recognizing, copying, or discriminating between different visual stimuli. Unlike patients with associative agnosia, those with apperceptive agnosia are unable to copy images.<ref>{{cite journal |vauthors=Riddoch MJ, Humphreys GW |title=Visual agnosia |journal=Neurol Clin |volume=21 |issue=2 |pages=501–20 |date=May 2003 |pmid=12916489 |doi= 10.1016/s0733-8619(02)00095-6}}</ref>
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 | [[Associative visual agnosia]] || Patients can describe visual scenes and classes of objects but still fail to recognize them. They may, for example, know that a fork is something you eat with but may mistake it for a spoon. Patients with associative agnosia are still able to reproduce an image through copying.
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 | [[Astereognosis]] || Also known as somatosensory agnosia, it is connected to tactile sense—that is, touch. Patient finds it difficult to recognize objects by touch based on its texture, size and weight. However, they may be able to describe it verbally or recognize same kind of objects from pictures or draw pictures of them. Thought to be connected to lesions or damage in [[somatosensory cortex]].
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 | [[Auditory agnosia]] || Auditory agnosia has been recognized since 1877.<ref name="Goldstein1974" /> With auditory agnosia, there is difficulty distinguishing environmental and non-verbal auditory cues including difficulty distinguishing speech from non-speech sounds even though hearing is usually normal.  There are two types of auditory agnosia: semantic associative and discriminative agnosia.  Semantic associative agnosia is associated with lesions to the left hemisphere, whereas discriminative agnosia is associated with lesions to the right hemisphere.<ref>{{cite journal|last=Vignolo|first=L. A|title=Auditory Agnosia|journal=Biological Sciences|year=1982|volume=298|pages=49–57|doi=10.1098/rstb.1982.0071|pmid=6125975|issue=1089|bibcode=1982RSPTB.298...49V|doi-access=}}</ref>
|-
 | [[Auditory verbal agnosia]] || Also known as pure word deafness (PWD). This presents as a form of meaning "deafness" in which hearing is intact but there is significant difficulty recognising spoken words as semantically meaningful.
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 | [[Autotopagnosia]] || Is associated with the inability to orient parts of the body, and is often caused by a [[lesion]] in the [[parietal lobe|parietal part]] of the posterior thalmic radiations.
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 | [[Cerebral achromatopsia]] || A difficulty in perceiving colors in which the world may appear drab or in shades of gray. Cerebral achromatopsia is caused by neurological damage.<ref>{{cite journal |vauthors=Cowey A, Alexander I, Heywood C, Kentridge R |title=Pupillary responses to coloured and contourless displays in total cerebral achromatopsia |journal=Brain |volume=131 |issue=Pt 8 |pages=2153–60 |date=August 2008 |pmid=18550620 |doi=10.1093/brain/awn110 |doi-access=free }}</ref><ref>{{cite journal|last=Woodward|first=T. S|author2=M. J Dixon|author3=K. T Mullen|author4=K. M Christensen|author5=D. N. Bub|title=Analysis of errors in color agnosia: A single case study|journal=Neurocase|year=1999|volume=5|issue=2|pages=95–108|doi=10.1093/neucas/5.2.95 }}</ref> There are two regions of the brain which specialize for color recognition, areas V4 and V8. If there is a unilateral lesion to area V4, a loss of color perception in only half of the visual field may result known as hemiachromatopsia.<ref name="M.S.Burns (2004)" /> Similar, but distinct, is [[color agnosia]], which involves having difficulty recognizing colors, while still being able to perceive them as measured by a color matching or categorizing task.<ref>{{cite journal |vauthors=Zeki S |title=A century of cerebral achromatopsia |journal=Brain |volume=113 |issue=Pt 6 |pages=1721–77 |date=1990 |pmid=2276043 |doi=10.1093/brain/113.6.1721 }}</ref>
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 | [[Cortical deafness]] || Refers to people who do not perceive any auditory information but whose hearing is intact.
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 | Environmental agnosia || It is the inability to locate a specific room or building that one is familiar with, as well as the inability to provide directions for how to arrive at a particular location.  These individuals experience difficulty with learning routes.  This form of agnosia is often associated with lesions to the bilateral or right hemisphere posterior regions.  It is also associated with prosopagnosia and Parkinson's disease.<ref name="M.S.Burns (2004)" />
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 | [[Finger agnosia]] || Is the inability to distinguish the fingers on the hand. It is present in lesions of the dominant [[parietal lobe]], and is a component of [[Gerstmann syndrome]].
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 | Form agnosia || Patients perceive only parts of details, not the whole object.
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 | [[Heterotopagnosia]] || Patients cannot point at another person's body parts, but can point at their own body parts.
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 | [[Integrative agnosia]] || Usually a patient has a form of associative agnosia or apperceptive agnosia.  However, in the case of integrative agnosia a patient falls in between a form of associative and apperceptive agnosia. This is where one has the ability to recognize elements of something but yet be unable to integrate these elements together into comprehensible perceptual wholes.
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 | Pain agnosia || Also referred to as [[congenital analgesia]], this is the difficulty perceiving and processing pain; thought to underpin some forms of self injury.
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 | [[Phonagnosia]] || Is the inability to recognize familiar voices, even though the hearer can understand the words used.<ref>{{cite journal |vauthors=Van Lancker DR, Cummings JL, Kreiman J, Dobkin BH |title=Phonagnosia: a dissociation between familiar and unfamiliar voices |journal=Cortex |volume=24 |issue=2 |pages=195–209 |date=June 1988 |pmid=3416603 |doi=10.1016/s0010-9452(88)80029-7|s2cid=28617313 |doi-access=free }}</ref>
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 | [[Prosopagnosia]] || Also known as faceblindness and facial agnosia: Patients cannot consciously recognize familiar faces, sometimes even including their own. This is often misperceived as an inability to remember names.
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| [[Pure alexia]] || Inability to recognize text. Patients with pure alexia often have damage to their corpus callosum, as well as damage to the left visual association areas.<ref name="M.S.Burns (2004)" />  Pure alexia involves not being able to read printed material, but these individuals still have the ability to write.  Individuals with pure alexia usually read words letter by letter.<ref>{{cite journal |author=Cherney LR |title=Aphasia, alexia, and oral reading |journal=Top Stroke Rehabil |volume=11 |issue=1 |pages=22–36 |year=2004 |pmid=14872397 |doi=10.1310/VUPX-WDX7-J1EU-00TB |s2cid=218644618 }}</ref>  However, individuals with pure alexia show a frequency effect.  They are able to read high frequency words better and faster than they can read low frequency words.<ref>{{cite journal|last=Sakurai|first=Y|title=Varieties of alexia from fusiform, posterior inferior temporal and posterior occipital gyrus|journal=Behavioural Neurology|year=2004|volume=15|issue=1–2|pages=35–50|doi=10.1155/2004/305194|pmid=15201492|pmc=5488613|doi-access=free}}</ref>
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 | Semantic agnosia || Those with this form of agnosia are effectively 'object blind' until they use non-visual sensory systems to recognise the object. For example, feeling, tapping, smelling, rocking or flicking the object, may trigger realisation of its semantics (meaning).<ref>{{cite journal |vauthors=Magnié MN, Ferreira CT, Giusiano B, Poncet M |title=Category specificity in object agnosia: preservation of sensorimotor experiences related to objects |journal=Neuropsychologia |volume=37 |issue=1 |pages=67–74 |date=January 1999 |pmid=9920472 |doi=10.1016/S0028-3932(98)00045-1|s2cid=1550842 }}</ref>
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 | [[Social-emotional agnosia]] || Sometimes referred to as expressive agnosia, this is a form of agnosia in which the person is unable to perceive facial expression, body language and intonation, rendering them unable to non-verbally perceive people's emotions and limiting that aspect of social interaction.
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 | [[Simultagnosia]] || The inability to process visual input as a whole.  The person instead processes faces, bodies, objects, rooms, places, pictures in a bit-by-bit fashion.<ref name="Coslett 1991">{{cite journal |vauthors=Coslett HB, Saffran E |title=Simultanagnosia. To see but not two see |journal=Brain |volume=114 |issue= 4|pages=1523–45 |date=August 1991 |pmid=1884165 |doi=10.1093/brain/114.4.1523 }}</ref>  When looking at a picture they can describe the parts of the picture but struggle to comprehend the picture as a whole.  Simultagnosia occurs in [[Bálint syndrome]]<ref name="Rizzo 2002">{{cite journal |vauthors=Rizzo M, Vecera SP |title=Psychoanatomical substrates of Bálint's syndrome |journal=J. Neurol. Neurosurg. Psychiatry |volume=72 |issue=2 |pages=162–78 |date=February 2002 |pmid=11796765 |pmc=1737727 |doi=10.1136/jnnp.72.2.162 }}</ref> but may also occur in brain injury. This condition can also be described by only seeing one object at a time. An example is having two cups in your visual field and only being able to see one at a time.
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 | [[Tactile agnosia]] || Impaired ability to recognize or identify objects by touch alone.<ref>{{cite journal |vauthors=Reed CL, Caselli RJ, Farah MJ |title=Tactile agnosia. Underlying impairment and implications for normal tactile object recognition |journal=Brain |volume=119 |issue=3 |pages=875–88 |date=June 1996 |pmid=8673499 |doi=10.1093/brain/119.3.875 |doi-access= }}</ref>
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 | [[Topographical disorientation]]  || Also known as topographical agnosia or topographagnosia, this is a form of visual agnosia in which a person cannot rely on visual cues to guide them directionally due to the inability to recognize objects. Nevertheless, they may still have an excellent capacity to describe the visual layout of the same place. Patients with topographical agnosia have the ability to read maps, but become lost in familiar environments.<ref>{{cite journal|last=Mendez|first=Mario F|author2=Cherrier, Monique M|title=Agnosia for scenes in topographagnosia|journal=Neuropsychologia|volume=41|issue=10|pages=1387–1395|doi=10.1016/S0028-3932(03)00041-1|year=2003|pmid=12757910|s2cid=9021982}}</ref>
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 | [[Visuospatial dysgnosia]] || This is a loss of the sense of "whereness" in the relation of oneself to one's environment and in the relation of objects to each other.  It may include [[constructional apraxia]], [[topographical disorientation]], optic ataxia, ocular motor apraxia, [[dressing apraxia]], and [[right-left confusion]].{{citation needed|date=August 2012}}
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 | [[Visual agnosia]] || Is associated with [[lesion]]s of the left [[occipital lobe]] and temporal lobes. Many types of visual agnosia involve the inability to recognize objects.<ref name="Green, 2005">{{cite journal |author=Greene JD |title=Apraxia, agnosias, and higher visual function abnormalities |journal=J. Neurol. Neurosurg. Psychiatry |volume=76 |issue=Suppl 5 |pages=v25–34 |date=December 2005 |pmid=16291919 |pmc=1765708 |doi=10.1136/jnnp.2005.081885 }}</ref>
|}

===Visual agnosia===
[[Visual agnosia]] is a broad category that refers to a deficiency in the ability to recognize visual objects. Visual agnosia can be further subdivided into two different subtypes: [[apperceptive agnosia|apperceptive visual agnosia]] and [[associative visual agnosia]].<ref name="Cognitive Psychology">{{cite book|last=Galotti]|first=Kathleen M.|title=Cognitive psychology : in and out of the laboratory|year=2010|publisher=Nelson|location=Canada|isbn=978-0-17-644065-7|edition=1st Canadian }}</ref>

Individuals with apperceptive visual agnosia display the ability to see contours and outlines when shown an object, but they experience difficulty if asked to categorize objects. Apperceptive visual agnosia is associated with damage to one hemisphere, specifically damage to the posterior sections of the right hemisphere.<ref name="Cognitive Psychology" />

In contrast, individuals with associative visual agnosia experience difficulty when asked to name objects. Associative agnosia is associated with damage to both the right and left hemispheres at the occipitotemporal border.<ref name="Cognitive Psychology" />  A specific form of associative visual agnosia is known as prosopagnosia.  [[Prosopagnosia]] is the inability to recognize faces.  For example, these individuals have difficulty recognizing friends, family and coworkers.<ref name="Cognitive Psychology" /> However, individuals with prosopagnosia can recognize all other types of visual stimuli.<ref>{{cite book|last1=Silverman|first2=Jay |last2=Friedenberg |first1=Gordon|title=Cognitive science : an introduction to the study of mind|publisher=SAGE|location=Thousand Oaks, Calif.|isbn=978-1-4129-7761-6|edition=2nd |date=2011-07-14}}</ref>

===Speech agnosia===

Speech agnosia, or [[auditory verbal agnosia]], refers to "an inability to comprehend spoken words despite intact hearing, speech production and reading ability". Patients report that they hear sounds being produced, but that the sounds are fundamentally unrecognizable or untranslatable.<ref name="The superior temporal sulcus">{{cite web|last1=Howard|first1=Harry|title=The superior temporal sulcus|url=http://www.tulane.edu/~howard/BrLg/t9-STS.html#id1|website=Brain and Language|access-date=6 December 2015|archive-url=https://web.archive.org/web/20151222094428/http://www.tulane.edu/~howard/BrLg/t9-STS.html#id1|archive-date=22 December 2015|url-status=dead|df=dmy-all}}</ref>

# EXAMINER: What did you eat for breakfast?
# PATIENT: Breakfast, breakfast, it sounds familiar but it doesn't speak to me. (Obler & Gjerlow 1999:45)

Despite an inability to process what the speaker is saying, some patients have been reported to recognize certain characteristic information about the speaker's voice (such as being a man or woman).<ref name="The superior temporal sulcus"/>