|Year : 2019 | Volume
| Issue : 3 | Page : 174-179
Reflected images processing and the diseases of the brain
Sadanandavalli Retnaswami Chandra1, Sumanth Shivaram2, Thomas Gregor Isaac3
1 Department of Neurology, Faculty Block, Neurocenter, NIMHANS, Bengaluru, Karnataka, India
2 Department of Neurology, NIMHANS, Bengaluru, Karnataka, India
3 Department of Psychiatry, NIMHANS, Bengaluru, Karnataka, India
|Date of Submission||05-Apr-2018|
|Date of Acceptance||10-Jun-2019|
|Date of Web Publication||05-Aug-2019|
Dr. Sadanandavalli Retnaswami Chandra
Faculty Block, Neurocenter, NIMHANS, Bengaluru - 560 029, Karnataka
Source of Support: None, Conflict of Interest: None
OBJECTIVES: The objective of the study reflected image processing defects in patients with dementia.
PATIENTS AND METHODS: Patients with memory complaint with Hindi Mental Status Examination (HMSE) score of 20 seen in the last 5 years were evaluated for mirror agnosia and mirror-image agnosia. Visual acuity was checked and corrected. A 45 cm × 45 cm plain mirror was used. It was kept at 30-cm distance from the patient. Their ability to recognize the mirror was confirmed. They were asked to identify reflected objects, ornaments, dress, self-image, image of caregiver, and two each of famous, smiling, crying, and novel faces.
RESULTS: A total number of patients with memory complaint were 512 and vascular dementia were 211. Others = 301 patients who had features suggestive of apraxia and agnosias = 69. Among the 69 patients, 65.2% were male and 34.8% female, mean age was 62.5. Disease wise distribution is frontotemporal dementia: 24.64%. Vascular dementia: 21.84%. Alzheimer's disease (AD): 20.29%. Unclassified: 14.49%. Mixed: 14.49%. diffuse Lewy body disease: 2.89%. Cortico basal degeneration syndrome (CBGD): 1.45%. The pattern of reflected image processing abnormality is mirror agnosia: 9 patients. Mirror-image agnosia: 11 patients.
CONCLUSIONS: Patients with AD showed wide variety of apraxias and mirror agnosia. Those with mirror-image agnosia did not show apraxias. In both groups, females were dominated. There is a clear delineation of features in patients with mirror agnosia and mirror-image agnosia. Mirror-image and mirror agnosia in degenerative dementias are not reported in the literature.
Keywords: Apraxias, consciousness, dementia, mirror agnosia, mirror-image agnosia, neural substrate of self-identification
|How to cite this article:|
Chandra SR, Shivaram S, Isaac TG. Reflected images processing and the diseases of the brain. Int J Health Allied Sci 2019;8:174-9
|How to cite this URL:|
Chandra SR, Shivaram S, Isaac TG. Reflected images processing and the diseases of the brain. Int J Health Allied Sci [serial online] 2019 [cited 2020 Feb 27];8:174-9. Available from: http://www.ijhas.in/text.asp?2019/8/3/174/263944
| Introduction|| |
When a light falls on a surface, it can be absorbed, reflected, or refracted. A ray traveling horizontally toward a reflecting surface of plane mirrors nature if it makes angle at point of incidence of zero, retraces its path. But if there are angulations, it gets reflected. If these lines are traced backward, they meet at a point. However, this meeting is not true or real and the image thus produced is virtual, it is erect and of the same size and same distance as that of the object from the mirror and it is laterally inverted, this is because when we look at our self in a mirror, it appears as a person standing behind the mirror, at the same distance and facing us, and therefore, it is a front to back inversion as mirrors just reflect what is in front of it. We imagine it as left-right reversal, as we believe the image to be real, our self, and not virtual. Mirror images of self are real-time images, have kinesthetic cues, expectation of self-related affective circuits are also activated. Failure in these mechanisms probably causes mirror-image agnosia.
Face recognition is an important tool in social cognition. Identification of faces can be disturbed in various neurological disorders, including strokes and degenerative diseases. Impaired face recognition can take many forms impaired ability to learn or recognize facial identity, facial emotions, differential problems in recognizing famous, familiar and novel faces, and/or impaired ability to recognize one's own reflected image described as mirror self-misidentification in patients with cerebrovascular events or mirror-image agnosia in neurodegeneration.,,
The most widely accepted model for face processing is the “two route model of face recognition” which was first developed by Bauer (1984) and then modified by Ellis and Young (1990). It involves two pathways – ventral and dorsal. Bauer described the ventral “visual-limbic” pathway as involving a pathway from the visual association cortex via the inferior longitudinal fasciculus to the temporal lobe and then to the adjoining limbic system, with the primary limbic “target” structure being the amygdala. He argued that this ventral pathway subserves emotion, memory, and learning functions that are modality specific to vision. The second pathway, the dorsal “visual-limbic” pathway, involves projections from the visual association cortex to the superior temporal lobe, then to the inferior parietal lobe, with extensive reciprocal connections with the cingulate gyrus, and subsequent connections with the hypothalamus. Bauer stated that the dorsal pathway was responsible for complex attentional functions, emotional arousal, and orientation to stimuli that had motivational significance. Self-reflected faces are different from other faces in the sense that we see our own faces only by looking into a mirror or other self-reflective surfaces and not directly, and therefore, we are familiar with our virtual image only. The ability to recognize self-reflected image is found only in humans and certain nonhuman primates which typically have large brains and show evidence of empathic behavior. Mirrored self-recognition has been understood as an engram of a unique social-cognitive function of a “self.” This notion is consistent with the developmental coemergence of empathic behavior and mirrored self-recognition in human infants. Functional imaging studies reveal that self faces are processed in a right-dominated way though both hemispheres are involved and the probable regions are the left fusiform gyrus, bilateral middle and inferior frontal gyri, and right precuneus.
In humans, face recognition develops very early in the first few months of life, but recognition of self-reflected images develops only by around 18–24 months of age. Persons who are unable to recognize their own faces believe that the reflected face is that of another person and that this person follows them around and appear wherever there is a reflective surface. These self-reflected images can be mistakes for anyone including stranger, thieves, enemies, or Gods. However, the patients with this unique condition retain their understanding of what a mirror is what it is used for and can even recognize the reflection of other people's faces and other objects. This is in contrast to patients with mirror agnosia where patients are unable to locate and objects reflected in a mirror and often looks for objects behind the mirror., Unfortunately, mostly these patients are mistaken as suffering from psychiatric disorders. Some researchers have also been able to create it in normal people by disrupting face processing or mirror knowledge as well as belief evaluation, using hypnotic suggestion.
The first attempts to investigate the neural correlates of self-recognition in nonpatients using modern neuroimaging and psychophysical techniques were conducted by Keenan et al. They developed a reaction time task that measured hand asymmetry when responding to one's own face as opposed to other faces that were either familiar or novel. They found a left-hand advantage when participants were responding to self-faces. A second experiment asked subjects to stop a movie of a morphed face that transitioned between a famous face and self-face when they thought that the image looked more like self. The participants stopped the movies sooner when responding with the left hand, i.e., because of contralateral motor control, they interpreted their findings as reflecting right hemisphere dominance of self-face recognition. With Wada test, injecting sodium pentobarbital into the carotid artery, it was found that when right hemisphere was anesthetized patients were more likely to report that the face was famous and miss self, but when the left hemisphere was anesthetized, they were more likely to report that the face looked like themselves. Right frontal activation in blood-oxygen-level-dependent imaging signal response is reported, while participants saw their own face. Other researchers found bilateral involvement and activation in the left fusiform gyrus, right frontal operculum, and right occipitotemporoparietal junction. The personally familiar faces activated regions in the right occipitotemporoparietal junction as well, suggesting that the right frontal operculum and left fusiform gyrus are critical regions involved in self-face recognition. Mirror neuron network is involved in differentiating self-face from others as per Uddin et al. Four patients reported to have mirror agnosia by Ramachandran et al. suffered from cerebrovascular accidents (CVA) on the right side by computerized tomography scan and lived in a strange new sensory world in certain aspects, and Bisiach and Luzzatti reported it as problem of internally created images not reporting scenes on the left field.
The evidence indicate that the brain possesses all faces and self-faces in relatively unique information processing system. Disorders of these areas might be involved in decline in social cognition, theory of mind, and self-image-related problems in disease states. We, therefore, wanted to study the problems in mirror image recognition in patients with memory problems.
| Patients and Methods|| |
Patients with memory complaint attending the neurology and geriatric outpatient department over the last 6 years were scrutinized, in detail with all mandatory workups. Those with mirror agnosia and mirror-image agnosia were isolated and evaluated. Patients with a minimum Hindi Mental Status Examination (HMSE) score of 20 only were evaluated. Visual acuity was checked and corrected. A 45 cm × 45 cm plain mirror was used. It was kept at 30 cm distance from the patient. Their ability to recognize the mirror was confirmed. They were asked to identify reflected objects, ornaments, dress, self-image, image of caregiver, two each of famous, smiling, crying, and novel faces which were taken from simple cards prepared. They were given common objects such as comb, pen, mobile phone, camera, book and were asked to identify. Thereafter, they were asked to use the objects they saw in the mirror, as well as to locate them in real space. Their impressions and reactions about other reflected images, while in front of the mirror, as well as away where recorded. When patients searched for images of objects inside the mirror, they were labeled as mirror agnosia and misinterpreted self-face were labeled as mirror-image agnosia [Table 1].
| Results|| |
A total numbers of patients with memory complaints were 512. Those with vascular dementia constituted 211. Others were 301 [Figure 1]. Patients who had features suggestive of apraxia and agnosias were 69. Among the 69 patients, 65.2% were male and 34.8% were female. Their mean age was 62.5 years. Frontotemporal dementia (FTD) constituted 24.64%, whereas vascular dementia – 21.84%, Alzheimer's disease (AD) – 20.29%, unclassified – 14.49%, mixed – 14.49%, diffuse Lewy body disease (DLBD) – 2.89%, and corticobasal ganglionic degeneration – 1.45% [Figure 2]. Among these patients, mirror-image agnosia was seen in 11 patients and mirror agnosia in 9 patients [Table 2] and [Table 3]. None of them had evidence of neglect by history or clock drawing test and line bisection. There were two patients who had both mirror agnosia and mirror-image agnosia.
|Figure 1: The distribution of vascular dementia in patients with memory impairment|
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Patients with AD showed wide variety of apraxias and mirror agnosia. Those with mirror-image agnosia did not show apraxias. In both groups, females were dominated. There is clear delineation of features in patients with mirror agnosia and mirror-image agnosia. Neuropsychiatric border zone symptoms are not uncommon in the early stage of cortical dementia. They are often mistaken as not organic, resulting in delay in appropriate investigations and treatments. Their average HMSE is high and therefore is fairly functional at the time of above symptoms. As the disease progresses to global deterioration, these symptoms disappear.
Most patients with mirror-image agnosia have difficulty in identifying their own faces in the mirror. But identify correctly most of the other faces and inanimate objects though few patients showed abnormality. They misidentified their own images as God, thief, friend, loved one, or stranger and reacted accordingly. Their everyday life was affected, as they were pathologically attracted to mirror. Patients broke the mirrors in their homes thinking somebody is inside causing damage to mirrors and themselves. Interestingly, females with AD seem more in this group. Their personal life was affected, as they were consistently considered as psychiatric. All of them received antipsychotic at some point [Videos 1 and 2].
| Discussion|| |
Classical mirror agnosia is described in the literature in patients with CVAs. Mirror-image and mirror agnosia in degenerative dementias have only very few case series. Reflected self-image processing defect is reported, as mirrored self-misidentification delusion in CVA', and they carried the delusion with them even while not in front of the mirror., Normal volunteers when they were with two mirrors one showing the direct virtual image and the second one the reflection of the image from the first mirror seen in a mirror kept behind, the person when he was touching some self-body part had a weird feel of extracorporeal existence, as there were mismatches between the visual information registered, proprioceptive inputs from self, and also touch information, and this was mediated by activation in the dorsolateral prefrontal cortex. Blank and colleagues reported the temporoparietal region crucial for producing the feel of one person behind the self. These observations when pursued might lead to some understanding of perception of self and consciousness. Our patients in both groups are unique, as they are described in degenerative dementia [Figure 3]. Mirror-image agnosia is different from the described mirror sign, as our patients imagined the reflected self-image as real images of someone else. They did not carry a delusional thought while away from the mirror. They showed a pleasurable attraction to talk to the image. It disappeared as disease advanced. Mirror agnosia is seen in the company of apraxias mostly unlike mirror-image agnosia and therefore probably involves dorsal tier dysfunction. The mirror-image agnosias are seen in isolation mostly and probably belong to ventral tier dysfunction. Occasional patients with diffuse atrophy show both types of mirror agnosia and mirror-image agnosia. Why females are more in this group with this phenomenon is probably because females have more AD and gender-based differences visuospatial skills show that females are generally less skilled in this aspect, unlike language. In Indian mythology, mirror-image agnosia is depicted in the story of Lord Krishna and Andal [Figure 4] and mirror agnosia in the story of Lord Narasimha when he could not recognize his own image as his own reflection because Lions do not recognize their own reflections.
|Figure 3: Right parietal atrophy in T-weighted magnetic resonance imaging sequence in a patient with mirror-image agnosia |
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| Conclusions|| |
Reflected self-images are special, as no individual has ever seen his or her real image. They have only seen the virtual image and matched it with the body schema. Mirror-image processing is a unique function of humans and not seen in animals and young children. All the patients showed parietal lobe atrophy more obvious on the nondominant side. Probably, there are special circuits for reflected image processing in real time and get selectively affected in the presence of neurodegeneration which is the factor operating in these two phenomena reported. The way they interpret the reflected images seems to depend on their premorbid education and occupation. Experiments in these areas are likely to give insights regarding understanding higher consciousness.
We have not conducted the tests elaborately using more than one mirror, as our patients were suffering from degenerative dementias. We have taken up a default mode network analysis in some of these patients using functional magnetic resonance imaging to understand if there is up- or downregulation of functional circuits in our patients with these phenomena. Attempts to evaluate with tasks could not be pursued as patients started reacting to the images. Our pursuits in this area have shown these phenomena in patients with Creutzfeldt-Jakob disease More Details (CJD), FTD, cortico basal degeneration (CBD), and DLBD, which we are in the process of analysis.
The authors would like to thank the Director, NIMHANS, Bengaluru, Karnataka, India.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]