11/46. Changes in personality and emotion following bilateral infarction of the posterior cerebral arteries.Remarkable changes in personality, emotion and behavior were observed in a 66-year-old female with bilateral infarction of the medial inferior portion at the temporo-occipital region. Aggressiveness, emotional lability and indifference were noted in the patient as psychiatric manifestation. No definite delirium, however, was observed. A neuroradiological examination revealed the lesions located at the territory of the posterior cerebral artery, which involved the hippocampus, the parahippocampal gyri, the fusiform gyri and the lingual gyri. Therefore, the psychiatric disturbances and the neuropsychological symptoms presented here are attributed to these lesions with the multiple infarctions in the brain. The present case is noteworthy for its unique changes in personality and emotion which in the literature have not reported to be caused following the vascular accident of the bilateral posterior cerebral artery.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
12/46. Conscious visual abilities in a patient with early bilateral occipital damage.A 21-year-old male presented with occipital lobes that were extensively damaged by bilateral infarcts present at birth. The absence of the striate cortex was confirmed with anatomic and functional MRI and high-resolution EEG. His cortical visual impairment was severe, but he retained a remarkable ability to see fast-moving stimuli. Horizontal optokinetic nystagmus could be elicited from either eye. Resolution acuity was close to normal providing the patient was allowed to move his head and eyes. The direction of motion in random-dot patterns could be discriminated with perfect accuracy at speeds above 2 deg/s, and the patient reported that he could 'see' the motion at fast but not at slow speeds. This conscious residual vision for motion is known as Riddoch's phenomenon, but it has never been reported in the complete absence of the striate cortex. functional neuroimaging revealed activation that was outside the motion-responsive regions of the extrastriate cortex. This case demonstrates remarkable plasticity in the human visual system and may have implications for understanding the functional organization of the motion pathways.- - - - - - - - - - ranking = 0.71428571428571keywords = motion (Clic here for more details about this article) |
13/46. First-order and second-order motion: neurological evidence for neuroanatomically distinct systems.An unresolved issue in visual motion perception is how distinct are the processes underlying 'first-order' and 'second-order' motion. The former is defined by spatio-temporal variations of luminance and the latter by spatio-temporal variations in other image attributes such as contrast or depth, for example. Using neuroimaging and psychophysics we present data from four neurological patients with unilateral and mostly cortical infarcts, which strongly suggest that first- and second-order motion have a different neural substrate. We found that from the early stages of processing, these two types of motions are mediated by two distinct pathways: first-order motion is carried out by mechanisms along the dorsal pathway in the occipital lobe, while the second-order motion by mechanisms mostly along the ventral pathway. The data reported here also suggest that different cortical regions may be in charge of processing direction-discrimination in second-order motion defined by different second-order attributes.- - - - - - - - - - ranking = 1.5714285714286keywords = motion (Clic here for more details about this article) |
14/46. Confused and disturbed behavior in the elderly following silent frontal lobe infarction.It is unclear whether silent frontal lobe infarction is truly asymptomatic; frontal behavioral syndromes following strokes have rarely been reported. We studied 12 elderly patients with silent frontal lobe infarction who were exhibiting confused and disturbed behavior. Ten were male and two female; their ages ranged from 68 to 79 (mean 78). Three groups of symptom clusters emerged: changes in mood and emotional behavior, cognitive deterioration with minor psychiatric symptoms, and a confusional state. When related to the CT scan location, three regions were identified: predominantly orbitofrontal, deep white matter and caudate, and border-zones, respectively. These findings were related to what is known about the neuroanatomic location of the lesions and the role of the frontal subcortical circuitry in relation to behavior. The different manifestations could be explained by damage to the frontal lobe or interruption of the complex frontal subcortical circuits.- - - - - - - - - - ranking = 0.14285714285714keywords = motion (Clic here for more details about this article) |
15/46. Visual command hallucinations in a patient with pure alexia.Around 25% of patients with visual hallucinations secondary to eye disease report hallucinations of text. The hallucinated text conveys little if any meaning, typically consisting of individual letters, words, or nonsense letter strings (orthographic hallucinations). A patient is described with textual visual hallucinations of a very different linguistic content following bilateral occipito-temporal infarcts. The hallucinations consisted of grammatically correct, meaningful written sentences or phrases, often in the second person and with a threatening and command-like nature (syntacto-semantic visual hallucinations). A detailed phenomenological interview and visual psychophysical testing were undertaken. The patient showed a classical ventral occipito-temporal syndrome with achromatopsia, prosopagnosia, and associative visual agnosia. Of particular significance was the presence of pure alexia. illusions of colour induced by monochromatic gratings and a novel motion-direction illusion were also observed, both consistent with the residual capacities of the patient's spared visual cortex. The content of orthographic visual hallucinations matches the known specialisations of an area in the left posterior fusiform gyrus--the visual word form area (VWFA)--suggesting the two are related. The VWFA is unlikely to be responsible for the syntacto-semantic hallucinations described here as the patient had a pure alexic syndrome, a known consequence of VWFA lesions. Syntacto-semantic visual hallucinations may represent a separate category of textual hallucinations related to the cortical network implicated in the auditory hallucinations of schizophrenia.- - - - - - - - - - ranking = 0.14285714285714keywords = motion (Clic here for more details about this article) |
16/46. Visual extinction for motion.PURPOSE: To alert clinicians to the heretofore undescribed visual behavioral phenomenon of visual extinction limited to motion. methods: Neuro-ophthalmological, neuropsychological and neuroimaging assessment of a 57-year-old man with vague visual complaints. RESULTS: Extinction limited to visual motion perception in the left hemifield was demonstrated. The visual defect was attributed to a lesion involving the right occipito-temporo-parietal region in the presence of a left posterior infarction. CONCLUSION: The importance of clinical examination for detection of this specific higher-order visual defect is stressed. The present observation may be helpful in understanding the effects of attention on visual perception and may have important implications for rehabilitation of patients with visual neglect.- - - - - - - - - - ranking = 0.85714285714286keywords = motion (Clic here for more details about this article) |
17/46. Affective aprosodia from a medial frontal stroke.BACKGROUND AND OBJECTIVES: Whereas injury to the left hemisphere induces aphasia, injury to the right hemisphere's perisylvian region induces an impairment of emotional speech prosody (affective aprosodia). Left-sided medial frontal lesions are associated with reduced verbal fluency with relatively intact comprehension and repetition (transcortical motor aphasia), but persistent affective prosodic defects associated with right medial frontal lesions have not been described. methods: We assessed the prosody of a man who sustained a right medial frontal cerebral infarction seven years prior. RESULTS: While propositional speech expression was normal including syntactic prosody, the patient was impaired at expressing emotions using prosody. His comprehension and repetition of prosody were also impaired but less so than expression. CONCLUSIONS: Right medial frontal lesions can induce an affective aprosodia that primarily impairs expression.- - - - - - - - - - ranking = 0.28571428571429keywords = motion (Clic here for more details about this article) |
18/46. Bilateral occipital-parietal hemorrhagic infarctions following chiropractic cervical manipulation.A 26-year-old woman presented with acute headache and hand-motion vision in both eyes. One day prior to presentation she went to her chiropractor for cervical manipulation. The patient had received 20 chiropractic manipulations over the previous two years. CT scan and MRI showed bilateral, symmetric occipital-parietal hemorrhagic infarctions. angiography revealed severe focal stenosis in the distal vertebral arteries bilaterally at the superior C1 level possibly representing dissections. There was also a pseudoaneurysm of the left vertebral artery at the C1 level. risk factors included chiropractic manipulation, recent fever, and therapies for polycystic ovarian disease. The patient showed slow, steady improvement in her vision. Twenty days following admission, vision was 20/20 OU. The improvement in her vision most likely reflects the reduction in swelling and absorption of blood at the site of the strokes.- - - - - - - - - - ranking = 0.14285714285714keywords = motion (Clic here for more details about this article) |
19/46. "Fou rire prodromique" associated with simultaneous bilateral capsular genu infarction.Pathological laughter is exaggerated, uncontrollable, and inappropriate laughter usually unrelated to a true emotion or a congruent mood. "Fou rire prodromique" is a rare form of prodromal pathological laughter of uncertain pathophysiology that heralds an ischaemic neurologic deficit. We report a case of prodromal pathological laughter marking the onset of bilateral capsular genu infarction. T2-weighted cranial magnetic resonance imaging (MRI) showed bilateral capsular genu infarction. There was also a diffusion defect in the same areas on diffusion-weighted imaging (DWI). Although it is known that bilateral subcortical lesions can cause pathological laughter, this is the first demonstration of simultaneous associated bilateral capsular genu infarction on cranial DWI MRI.- - - - - - - - - - ranking = 0.14285714285714keywords = motion (Clic here for more details about this article) |
20/46. Abulia: no will, no way.Abulia refers to impaired ability to perform voluntary actions, show initiative, make decisions along with decrease in movements, speech, thought and emotional reactions. We describe here two patients who developed this condition following bilateral insult to different sites in the centromedial core of the brain, the first following the cerebral venous thrombosis and the second after the right ACA and MCA infarct. Both these patients improved following treatment with bromocriptine. These cases are described for proper identification and management by the clinicians.- - - - - - - - - - ranking = 0.14285714285714keywords = motion (Clic here for more details about this article) |
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