1/37. Impaired declarative memory for emotional material following bilateral amygdala damage in humans.Everyday experience suggests that highly emotional events are often the most memorable, an observation supported by psychological and pharmacological studies in humans. Although studies in animals have shown that nondeclarative emotional memory (behaviors associated with emotional situations) may be impaired by lesions of the amygdala, little is known about the neural underpinnings of emotional memory in humans, especially in regard to declarative memory (memory for facts that can be assessed verbally). We investigated the declarative memory of two rare patients with selective bilateral amygdala damage. Both subjects showed impairments in long-term declarative memory for emotionally arousing material. The data support the hypothesis that the human amygdala normally enhances acquisition of declarative knowledge regarding emotionally arousing stimuli.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
2/37. rehabilitation outcome in a patient awakened from prolonged coma.BACKGROUND: This article describes the rehabilitation of a patient recovering from a prolonged coma (defined as lasting longer than 4 weeks). The case is noteworthy because it exemplifies the possibilities and difficulties entailed in treating these patients, who are often regarded as too severely impaired to justify intensive rehabilitation efforts. CASE REPORT: The patient is a 28-year old Polish male, unmarried, who suffered serious closed head injuries in an automobile accident in April of 1999. He was in a comatose state for more than two months, with a GCS score of 5. When admitted for rehabilitation he was bedridden, with global aphasia, agraphia, limb apraxia, and executive dysfunction. The rehabilitation program developed for him is described in detail. RESULTS: Over the course of rehabilitation, which began in December 1999 and continues to this writing, the patient has regained locomotion capabilities (though with impairments), and his speech has improved considerably. The apraxia has largely resolved, and he is able to write his name and copy words. He is now capable of performing many activities of daily living. CONCLUSIONS: A comprehensive program of rehabilitation characterized by a strategic, heuristic approach is capable of achieving a good outcome even in very difficult cases, such as prolonged coma.- - - - - - - - - - ranking = 0.1keywords = motion (Clic here for more details about this article) |
3/37. Neuropsychological testing following head injuries: prosopagnosia without visual field defect.Assessment of residual cerebral dysfunction in the post-traumatic patient poses considerable problems particularly when the neurological examination yields minimal or equivocal findings. The clinical picture is frequently complicated by emotional disturbance not easily differentiated from "post-traumatic neurosis." This report describes such a patient whose disorder was elicidated by neuropsychological testing. Numerous studies have established the validity of neuropsychological tests particularly when they are interpreted by psychologists specifically trained in their use. These procedures are also useful in differentiating patients with neurologic complaints of a nonorganic etiology from patients with similar complaints secondary to confirmed brain lesions. Although the findings reported here pertain to a patient exhibiting a rare neurologic consequence of closed head injury, the methods employed are applicable to subtle behavioral manifestations of diverse etiologies. Neurophyshological findings in a patient unable to recognize faces of familiar persons (prosopagnosia) disclosed a severe impairment of visual perception despite intact visual acuity and fields. The prosopagnosia was also associated with a pervasive memory deficit without dementia. Our results challenge current concepts of prosopagnosia and support the need for neuropsychological evaluation of post-traumatic patients.- - - - - - - - - - ranking = 0.1keywords = motion (Clic here for more details about this article) |
4/37. Dissociation of affective modulation of recollective and perceptual experience following amygdala damage.It has been suggested that similar neural mechanisms may underlie the affective modulation of both recollective and perceptual experience. A case is reported of a patient who has bilateral amygdala damage and marked impairment in the perception of emotion, particularly fear. The patient DR and 10 healthy control subjects (matched for school leaving age, intelligence quotient, and non-emotional memory performance) were shown a series of slides accompanied by an emotionally arousing narrative. One week later DR and the controls were given a surprise memory test for this material. In addition, they completed a verbal memory test using emotionally arousing stimuli. Both DR and the healthy control subjects showed a normative pattern of enhanced memory for emotional material. On the basis of these results and the previously demonstrated impairment of perception of emotion in this patient, it is concluded that different neural mechanisms may underlie affective modulation of recollective and perceptual experience.- - - - - - - - - - ranking = 0.6keywords = motion (Clic here for more details about this article) |
5/37. Cerebellar atrophy as a delayed manifestation of chronic carbon disulfide poisoning.A 70-year-old man developed a slowly progressive cerebellar syndrome after having been exposed to carbon disulfide (CS2) in a viscose rayon plant for 27 years. ataxia, dysmetria, dysarthria and adiadochokinesia appeared 7 years after retirement from work (at age 54), and were later accompanied by cognitive deterioration, dysmnesia, spatio-temporal disorientation, emotional lability, and paranoid-obsessive disturbances. brain computed tomography (CT) and magnetic resonance imaging (MRI) showed advanced global cerebellar atrophy, and a picture of less severe cerebrocortical atrophy. The case illustrates the possibility of chronic toxic encephalopathy among patients with previous long-term exposure to CS2. In such instances, cerebellar damage may develop as an exceptional, delayed manifestation of neurotoxicity: brain imaging techniques can significantly contribute to the diagnosis and follow-up, in addition to occupational anamnesis and neuropsychiatric evaluation. The patient presented also serves as a remainder that neurodegenerative disorders of apparently unknown origin sometimes derive from occupational toxic exposures suffered in the past. The clinical manifestations may appear several years after retirement from work, when the effects of toxic damage combine with age-related neuronal loss to overcome the brain functional reserve.- - - - - - - - - - ranking = 0.1keywords = motion (Clic here for more details about this article) |
6/37. Behavioural disturbances following Japanese B encephalitis.Clinically, Japanese B encephalitis (JBE) is often overlooked as its occurrence in Western countries is rare. However, its neurological, cognitive and psychiatric sequelae constitute a major public health problem in the far east where JBE is endemic. European and American subjects may however experience the JBE when returning from a far east journey. In such cases, misdiagnosis is frequent because of the unawareness of psychiatrists and physicians. The present review, therefore, documents the behavioural and cognitive sequelae of JBE. This reactivates the debate concerning the vaccination against the virus all the more that the literature enlightens the importance of the vaccination for those who undertake frequent and extensive tourist excursions to the Orient but still discusses it for occasional travellers. Following is a case-report of a young western European post-graduate student who has contracted JBE by experiencing an acute febrile delirium during an unusual short stay in South East Asia. Pyramidal syndrome, Parkinsonism and amnesia were the prominent acute deficits. Whereas these faded in great part during convalescence, emotional and behavioural instability associated with affective involvement, obsessive-compulsive symptoms and cognitive impairments appeared. A partial recovery was however obtained with neuroleptics, lithium and following electro-convulsive therapy. Organic personality syndrome was persistent and thereafter constituted the main sequelae syndrome. Hypersomnia and several enuretic episodes persisted.- - - - - - - - - - ranking = 0.1keywords = motion (Clic here for more details about this article) |
7/37. Developmental outcomes after early prefrontal cortex damage.The neuropsychological bases of cognitive, social, and moral development are minimally understood, with a seemingly wide chasm between developmental theories and brain maturation models. As one approach to bridging ideas in these areas, we review 10 cases of early prefrontal cortex damage from the clinical literature, highlighting overall clinical profiles and real life developmental outcomes. Based on these cases, there is preliminary evidence to support distinctive developmental differences after: (1) dorsolateral, (2) mesial, and (3) orbital-polar prefrontal lesions, for more profound impairments after bilateral damage, and possibly for recovery differences after very early vs. later childhood lesion onset. Further case and group studies are needed to confirm reliable effects of specific lesion locations, the influence of age of lesion onset, and related experiential and treatment variables in determining adult outcomes. Rather than a single underlying deficit associated with early prefrontal cortex damage, we interpret the findings to suggest that it is the altered integration and interplay of cognitive, emotional, self-regulatory, and executive/metacognitive deficits that contribute to diverse developmental frontal lobe syndromes. The findings support the fundamental importance of prefrontal cortex maturation in protracted cognitive, social-emotional, and moral development.- - - - - - - - - - ranking = 0.2keywords = motion (Clic here for more details about this article) |
8/37. acceleration perception and spatial distortion in a left unilateral neglect patient.To explain relative leftward overextension in a line extension task by left unilateral neglect subjects, Bisiach et al. (1998) suggested that the representation of space is distorted--i.e., dilated towards the left side. If perception of the velocity of a moving stimulus is due to a calculation of the distance covered per unit time in representational space, then a stimulus with uniform linear motion should be perceived as decelerating when moving leftwards in the visual field of a subject with left unilateral neglect. We investigated the perception of acceleration in a patient with left unilateral neglect and spatial distortion (revealed as relative left overextension in a line extension task) using a task in which the stimuli were right and left moving targets with variable acceleration. The patient's ability to perceive acceleration was much lower (higher acceleration threshold) for leftward movements than rightward movements. Fourteen months later unilateral neglect had improved, and the relative left overextension and decreasing acceleration threshold for leftward movements were reduced. By contrast, alterations in the perception of acceleration for leftward movements were not found in a patient with left unilateral neglect and left underextension and in a patient with right brain damage and left hemianopia. These findings in one patient with left spatial unilateral neglect and a relative left overextension in a line extension task are consistent with the hypothesis that representational space is distorted, with a disproportionate leftward expansion, that affects perception of movement.- - - - - - - - - - ranking = 0.1keywords = motion (Clic here for more details about this article) |
9/37. Negative emotions and anosognosia.patients with anosognosia fail to acknowledge, or feel distressed by, their disability. Given the recent suggestion that right (frontal) systems are selectively involved in negative emotions, it might be claimed that anosognosia results from a disruption in negative emotions. This is not consistent with the finding that some anosognosic patients exhibit substantial fluctuations in emotion, including the experience of negative emotions such as sadness. The present study investigates a patient (IW) with a right convexity lesion and anosognosia. He reported being frequently overcome by powerful emotions, especially sadness. IW was assessed on a self-report emotion questionnaire, where his reports were typically of higher levels of emotion than the control group. He was also assessed on the more indirect measure of Affective Story Recall. Here his pattern of emotional experience was similar to that of two control groups, one of which consisted of non-anosognosic patients with hemiparesis. His performance on Story Recall was notable in that he directed his emotions to a different 'object' to that of controls (other vs. self, respectively). These findings are not consistent with any claim that anosognosia results from an absence of negative emotions.- - - - - - - - - - ranking = 1.4keywords = motion (Clic here for more details about this article) |
10/37. Specific retinotopically based magnocellular impairment in a patient with medial visual dorsal stream damage.We report here retinotopically based magnocellular deficits in a patient with a unilateral parieto-occipital lesion. We applied convergent methodologies to study his dorsal stream processing, using psychophysics as well as structural and functional imaging. Using standard perimetry we found deficits involving the periphery of the left inferior quadrant abutting the horizontal meridian, suggesting damage of dorsal retinotopic representations beyond V1. Retinotopic damage was much more extensive when probed with frequency-doubling based contrast sensitivity measurements, which isolate processing within the magnocellular pathway: sensitivity losses now encroached on the visual central representation and did not respect the horizontal meridian, suggesting further damage to dorsal stream retinotopic areas that contain full hemi-field representations, such as human V3A or V6. Functional imaging revealed normal responses of human MT to motion contrast. Taken together, these findings are consistent with a recent proposal of two distinct magnocellular dorsal stream pathways: a latero-dorsal pathway passing to MT and concerned with the processing of coherent motion, and a medio-dorsal pathway that routes information from V3A to the human homologue of V6. Anatomical evidence was consistent with sparing of the latero-dorsal pathway in our patient, and was corroborated by his normal performance in speed, direction discrimination and motion coherence tasks with 2D and 3D objects. His pattern of dysfunction suggests damage only to the medio-dorsal pathway, an inference that is consistent with structural imaging data, which revealed a lesion encompassing the right parieto-occipital sulcus.- - - - - - - - - - ranking = 0.3keywords = motion (Clic here for more details about this article) |
| | Next -> |