Agnosia for mirror stimuli: a new case report with a small parietal lesion.
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ABSTRACT:
SUBMITTER: Martinaud O
PROVIDER: S-EPMC4263918 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one's own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. MATERIAL AND METHODS: Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. RESULTS: Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. DISCUSSION: Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery of how brain handles reflected self-images. CONCLUSION: A new observation involving failure to recognize reflected self-images is reported.
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Project description:We report the case of patient M, who suffered unilateral left posterior temporal and parietal damage, brain regions typically associated with language processing. Language function largely recovered since the infarct, with no measurable speech comprehension impairments. However, the patient exhibited a severe impairment in nonverbal auditory comprehension. We carried out extensive audiological and behavioral testing in order to characterize M's unusual neuropsychological profile. We also examined the patient's and controls' neural responses to verbal and nonverbal auditory stimuli using functional magnetic resonance imaging (fMRI). We verified that the patient exhibited persistent and severe auditory agnosia for nonverbal sounds in the absence of verbal comprehension deficits or peripheral hearing problems. Acoustical analyses suggested that his residual processing of a minority of environmental sounds might rely on his speech processing abilities. In the patient's brain, contralateral (right) temporal cortex as well as perilesional (left) anterior temporal cortex were strongly responsive to verbal, but not to nonverbal sounds, a pattern that stands in marked contrast to the controls' data. This substantial reorganization of auditory processing likely supported the recovery of M's speech processing.
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Project description:BACKGROUND:Dieulafoy's lesion is an uncommon but important cause of recurrent upper gastrointestinal bleeding. Extragastric location of Dieulafoy's lesion is rare. We report two cases of Dieulafoy's lesion of the duodenum and discuss the management of this extremely uncommon entity. CASE PRESENTATION:Two cases of massive upper gastro-intestinal bleeding in young adults due to Dieulafoy's lesion of the duodenum are reported. Endoscopic diagnosis was possible in both cases. Hemostasis was achieved successfully by endoscopic adrenaline injection. The endoscopic appearance, pitfalls in the diagnosis and management of this rare lesion are discussed. CONCLUSIONS:Endoscopic diagnosis of extragastric Dieulafoy's lesion can be difficult because of the small size and obscure location of the lesion. Increased awareness and careful and early endoscopic evaluation following the bleeding episode are the key to accurate diagnosis. Adrenaline injection is one of the important endoscopic modalities for control of bleeding.
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Project description:Introduction and importance Choosing the optimal surgical approach for intractable pneumothorax can be challenging for surgeons. Case presentation A case describing the management of intractable pneumothorax has been presented. Clinical discussion Resection is not suitable in a stiff lung from repeated pleurodesis, and multiple air leakage points would make it more intricate.The ideal alternative is the use of another material to cover the entire lesion. Conclusion A thickened parietal pleura covering is an effective surgical approach for intractable pneumothorax. Highlights • Selecting an optimal surgical approach for intractable pneumothorax is challenging.• A thickened parietal pleura covering can effectively control intractable pneumothorax.• The procedure is suitable for patients with stiff lung and persistent air leakage at multiple points.
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Project description:Mirror syndrome is a rare pregnancy complication, life-threatening to mother and fetus. Increasing survival rates of congenital heart disease into reproductive age mean that complications like Mirror syndrome in this population may be more challenging to diagnose, given overlapping signs of edema in cases of heart failure exacerbation. We report a case of a pregnant woman with a history of unspecified congenital heart disease, presenting with swelling and distension, with diagnostic findings not consistent with preeclampsia. Her course was complicated by dyspnea, oliguria, and fetal hydrops. A cesarean delivery under neuraxial anesthesia was performed. We review the clinical manifestations of Mirror syndrome and discuss anesthetic and obstetric management considerations for this condition.
| S-EPMC6712568 | biostudies-literature
Project description:IntroductionVerbal auditory agnosia is rarely caused by mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. Lactate acidosis, which is the adverse effect of metformin, has proposed links to mitochondrial dysfunction and may trigger clinical features of mitochondrial diseases.Case presentationA 43-year-old right-handed man presented to our emergency department with acute onset fever and headache accompanied by impaired hearing comprehension. He could communicate well through handwritten notes but could not understand what others were saying. He had been diagnosed as having diabetes mellitus 2 months prior to this event. Vildagliptin 100 mg/day and metformin 1,700 mg/day were prescribed for glucose control. Laboratory tests revealed elevated lactate levels in serum and cerebrospinal fluid of the patient. Brain MRI disclosed bilateral temporal lesions. Acute encephalitis with temporal involved was initially diagnosed and acyclovir was given empirically. However, follow-up MRI after acyclovir treatment revealed a progression of prior lesions. Further mitochondrial genome analysis revealed a mitochondrial DNA point mutation at position 3,243 (m.3243A > G) with 25% heteroplasmy, which is compatible with MELAS. His clinical symptoms and serum lactate levels were improved after discontinuing the metformin use.ConclusionsTo our knowledge, this is the first report of a patient having late-onset MELAS syndrome that manifested as acute verbal auditory agnosia, which was identified after the patient began using metformin. Metformin is known to inhibit mitochondrial function and could trigger clinical features of MELAS syndrome. We encourage clinicians to maintain a high level of awareness that diabetes mellitus can be caused by mitochondrial disease and to exercise caution in the prescription of metformin.
| S-EPMC8990297 | biostudies-literature
Project description:Cortical reorganization of visual and object representations following neural injury was examined using fMRI and behavioral investigations. We probed the visual responsivity of the ventral visual cortex of an agnosic patient who was impaired at object recognition following a lesion to the right lateral fusiform gyrus. In both hemispheres, retinotopic mapping revealed typical topographic organization and visual activation of early visual cortex. However, visual responses, object-related, and -selective responses were reduced in regions immediately surrounding the lesion in the right hemisphere, and also, surprisingly, in corresponding locations in the structurally intact left hemisphere. In contrast, hV4 of the right hemisphere showed expanded response properties. These findings indicate that the right lateral fusiform gyrus is critically involved in object recognition and that an impairment to this region has widespread consequences for remote parts of cortex. Finally, functional neural plasticity is possible even when a cortical lesion is sustained in adulthood.
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Project description:BackgroundPeripheral neuropathy after surgical treatment is an under recognized potential untoward event. Pelvic surgery may be associated with nerve lesions by essentially three main mechanisms: transection, entrapment and pressure-stretching; the latter is the modality most frequently linked to patient's positioning on the operating room table.Presentation of the caseA 25 years old woman, after undergoing a laparoscopic gynaecologic procedure lasted >3 hours, on postoperative day one presented with numbness over her lateral right leg and dorsum of the foot, right foot drop and gait instability due to compression-stretching of the right superficial peroneal nerve.DiscussionPatient's diagnostic work up, treatment and outcome are reported and measures on how to prevent the occurrence of such type of lesion are outlined together with the importance of an early postoperative diagnosis in order to avoid permanent nerve damage.ConclusionSuch lesions are sometimes so unexpected that delayed diagnosis leads to damages which are difficult or impossible to repair. Primary prevention plays a key role and it is realized by adhering to specific protocols. In the occurrence of the lesion a prompt diagnosis is highly recommendable and a comprehensive therapeutic plan is necessary to correctly address the specific pathology.
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Project description:Mirror neurons, as originally described in the macaque, have two defining properties [1, 2]: They respond specifically to a particular action (e.g., bringing an object to the mouth), and they produce their action-specific responses independent of whether the monkey executes the action or passively observes a conspecific performing the same action. In humans, action observation and action execution engage a network of frontal, parietal, and temporal areas. However, it is unclear whether these responses reflect the activity of a single population that represents both observed and executed actions in a common neural code or the activity of distinct but overlapping populations of exclusively perceptual and motor neurons [3]. Here, we used fMRI adaptation to show that the right inferior parietal lobe (IPL) responds independently to specific actions regardless of whether they are observed or executed. Specifically, responses in the right IPL were attenuated when participants observed a recently executed action relative to one that had not previously been performed. This adaptation across action and perception demonstrates that the right IPL responds selectively to the motoric and perceptual representations of actions and is the first evidence for a neural response in humans that shows both defining properties of mirror neurons.
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