Neurodegeneration and mirror image agnosia

Abstract

Background:Normal Percept with abnormal meaning (Agnosias) has been described from nineteenth century onwards. Later literature became abundant with information on the spectrum of Prosopagnosias. However, selective difficulty in identifying reflected self images with relatively better cognitive functions leads to problems in differentiating it from non-organic psychosis.Aim:In the present study, we investigated patients with dementia who showed difficulty in identifying reflected self images while they were being tested for problems in gnosis with reference to identification of reflected objects, animals, relatives, and themselves and correlate with neuropsychological and radiological parameters.Patients and Methods:Five such patients were identified and tested with a 45 cm × 45 cm mirror kept at 30-cm distance straight ahead of them.Results:Mirror image agnosia is seen in patients with moderate stage posterior dementias who showed neuropsychological and radiological evidence of right parietal dysfunction.Conclusion:Interpretation of reflected self images perception in real time probably involves distinct data-linking circuits in the right parietal lobe, which may get disrupted early in the course of the disease.

Immediate effect of adding mirror visual feedback to lateral weight-shifting training on the standing balance control of the unilateral spatial neglect model

“…MT is a simple treatment that improves USN and may positively affect visuospatial neglect 18,19) . In contrast, the MVF indicated a reverse effect of postural control and behavioral response in severe neglect and confuses some patients, especially in recognizing mirror image in mirror agnosia case [20][21][22][23] . Hence, the continuity effect of the MVF was temporal and further investigation for alleviating neglect is needed [24][25][26] .…”

Processing of reflected mirror images in the brain - Physiological basis, pathomechanisms and therapeutic options

“…Here the hypothesis is nothing is seen on left field. Image seen is believed by brain to be inside the mirror [18]. The right parietal infarct fails to produce the needed physiological mental diplopia in recognizing the mirror image as virtual resulting in mirror image agnosia [18].…”

“…Image seen is believed by brain to be inside the mirror [18]. The right parietal infarct fails to produce the needed physiological mental diplopia in recognizing the mirror image as virtual resulting in mirror image agnosia [18]. According to a study by Beis et al [17] his patients with cerebrovascular accident having mirror agnosia couldn't modify their behaviour even after object was clearly shown in real space but patients with mirror ataxia on the contrary learned to reach the real object easily.…”

Alzheimer's disease

“…Dual-task gait assessments may be included as an add-on diagnostic tool for early differentiation of these two conditions 34 . We also described a unique phenomenon of misidentifying self-image as another person resulting in severe caregiver problem, and termed as mirror image agnosia 39 40 . For assessing progression and quantifying loss in rural regions, a study was conducted comparing quantitative voxel-based volumetric assessment of brain for visual quantification of electroencephalography (EEG).…”