non-standardized
ASSEssmentS
Often times in-depth neuropsychological testing is not available. During these times, an Occupational Therapist may be referred to assess an individual with recognition deficits. To assess for agnosia, an Occupational Therapist may first present the individual with several different common objects and asked him or her to identify it. If the individual exhibits word-finding difficulties, provide three choices and ask him or her to nod with their head yes or no to indicate the correct answer (Saya, 2010). If the individual has difficulties with naming at least 4 out of 5 objects, visual agnosia may be present. This number is not set so do not be afraid to repeat with a different set of objects, especially if agnosia is suspected. It is important to note that this non-standardized assessment is a screening tool for agnosia because to diagnose agnosia, neuropsychological testing and brain imaging should be performed.
Remember to repeat this assessment with other unaffected modalities (i.e., auditory and tactile) because agnosia affects only a single modality. An individual with visual agnosia would still be able to recognize objects if given the opportunity to touch or hear its characteristics being described. To assess for auditory agnosia and tactile agnosias, present the individual with different common sounds and objects and then repeat using the other sensory stimuli. The individual should be able to correctly recognize the stimuli when presented in the unaffected modalities.
Remember to repeat this assessment with other unaffected modalities (i.e., auditory and tactile) because agnosia affects only a single modality. An individual with visual agnosia would still be able to recognize objects if given the opportunity to touch or hear its characteristics being described. To assess for auditory agnosia and tactile agnosias, present the individual with different common sounds and objects and then repeat using the other sensory stimuli. The individual should be able to correctly recognize the stimuli when presented in the unaffected modalities.
specific agnosia
assessments
There are current no protocol for assessment of different types of agnosias in the literature. However, there are some literature on how to assess specific agnosias after a general assessment (neuropsychological testing to rule out alternative explanations and brain imaging) is completed.
PROSOPAgnosia
Prosopagnosia refers to the inability to recognize and name familiar faces. This type of visual agnosia can be assessed through the presentation of photographs of well-known individuals, such as celebrities and family members. Burns (2004) suggests that the examiner use a variety of faces (movie stars, athletes, public figures) to make sure the faces are culturally and age appropriate. The assessment begins with asking the individual with agnosia to name a set of photographs. Afterwards, doing the same but with a different set of photographs. For any face that the individual cannot name, the examiner should check his or her knowledge of the person identified in the photograph. This can be done by asking the individual questions about the person in the photograph. Individuals with prosopagnosia will know that a face is a face, be able to identify features of the face, and be able to recognize the person if he or she speaks (Burns, 2004). However, the individual will often have difficulties recognizing the familiar faces.
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tactile agnosia
As mentioned before, individuals with tactile agnosia usually have lesions within only one side of the brain (unilateral). As a result, the hand that is contralateral to the lesion would be agnostic. This unilateral nature allows for an advantage in assessing for tactile agnosia. Assessment can be done through a direct comparison of the agnostic hand with the non-agnostic hand and the individual's ability to recognize the same object. If the agnostic hand does not have the ability to recognize an object as compared to the non-agnostic hand, this means that difficulties recognizing objects with the agnostic hand cannot be attributed to labelling problems or a lack of knowledge about the objects (Reed, 2010).