1/9. Involuntary masturbation as a manifestation of stroke-related alien hand syndrome.alien hand syndrome is a perplexing and uncommon clinical diagnosis. We report an unusual manifestation of alien hand syndrome in a 73-yr-old man with a right anterior cerebral artery infarct affecting the right medial frontal cortex and the anterior portion of the corpus callosum. We conclude that alien hand syndrome should be considered in patients who present with a feeling of alienation of one or both upper limbs accompanied by complex purposeful involuntary movement.- - - - - - - - - - ranking = 1keywords = alien hand syndrome, hand syndrome, alien hand, alien, hand (Clic here for more details about this article) |
2/9. Interhemispheric reorganization of motor hand function to the primary motor cortex predicted with functional magnetic resonance imaging and transcranial magnetic stimulation.The objective of this study was presurgical assessment of reorganization of motor hand function in an 11-year-old girl with intractable epilepsy and a right-sided hemiplegia resulting from an extensive perinatal left hemispheric stroke. Prior to a left functional hemispherectomy, functional magnetic resonance imaging (MRI) showed that both nonparetic and paretic motor hand function predominantly activated the right primary motor cortex, whereas no activation was found in the left hemisphere. transcranial magnetic stimulation of the right central area yielded responses in both the nonparetic and the paretic hand, whereas no responses were obtained after stimulation of the affected hemisphere. Both techniques indicated that motor function was mediated by corticospinal fibers originating from the undamaged (primary) motor cortex and predicted no further loss of motor hand function after surgery. Indeed, subsequent functional hemispherectomy induced no new sensorimotor deficits. Functional MRI was repeated 22 months after surgery and matched preoperative sensorimotor functional MRI findings, confirming reorganization of the primary motor cortex. No additional reorganization was introduced by surgery.- - - - - - - - - - ranking = 5.0210898886069E-5keywords = hand (Clic here for more details about this article) |
3/9. Hyperfamiliarity for unknown faces after left lateral temporo-occipital venous infarction: a double dissociation with prosopagnosia.Right hemisphere dominance in face processing is well established and unilateral right inferior temporo-occipital damage can result in prosopagnosia. Here, we describe a 21-year-old right-handed woman with acute impairment in face recognition that selectively concerned unfamiliar faces, following a focal left lateral temporo-occipital venous infarct. She was severely impaired in discerning that unknown people seen in everyday life were unfamiliar, although she had no difficulty recognizing familiar people. Thus, she had no prosopagnosia, but abnormal 'hyperfamiliarity' for unknown faces. Her difficulty was not accompanied by delusions or deficits in discrimination, identification or memory for faces. Standard neuropsychological testing showed that her recognition of familiar faces was entirely normal. By contrast, her sense of personally knowing faces was severely impaired when unknown faces evoked weak signals of familiarity based on spurious cues, to the extent that she would misattribute fame to faces that were unknown but to which she had been incidentally exposed on a prior occasion. Priming experiments also revealed that, unlike normal subjects, she made familiarity judgements without accessing semantic identity representations. Moreover, in face recognition tests, she generally showed bias in that she relied more on right-hemisphere strategies to identify global traits and less on left-hemisphere processes compared with healthy subjects. This case provides novel evidence for a differential contribution of the two hemispheres to face recognition. Hyperfamiliarity for unknown faces might arise from an imbalance between reciprocal hemispheric functions in face recognition, with relative hypoactivation of left hemisphere processes but hyperactivation of right-hemisphere processes for retrieving stored associations about people, linking seen faces to representations of affective and personal relevance. Hence, abnormal bias in attributing some personal meaning to unknown faces could be evoked by spurious signals of familiarity based on irrelevant affective associations in the right hemisphere.- - - - - - - - - - ranking = 6.2763623607586E-6keywords = hand (Clic here for more details about this article) |
4/9. Deterioration of pre-existing hemiparesis brought about by subsequent ipsilateral lacunar infarction.Mechanisms of post-stroke recovery are still poorly understood. Recent evidence suggests that cortical reorganisation in the unaffected hemisphere plays an important role. A 59 year old man developed a small lacunar infarct in the left corona radiata, which then caused marked deterioration in a pre-existing left hemiparesis that had resulted from an earlier right putaminal haemorrhage. Functional magnetic resonance imaging showed that the paretic left hand grip activated the ipsilateral left motor areas, but not the right hemispheric motor areas. This suggests that partial recovery of the left hemiparesis had been brought about by cortical reorganisation of the left hemisphere and intensification of the uncrossed corticospinal tract. The subsequent small infarct may have damaged the uncrossed tract, thereby causing the pre-existing hemiparesis to deteriorate even further.- - - - - - - - - - ranking = 6.2763623607586E-6keywords = hand (Clic here for more details about this article) |
5/9. Cognitive and motor functioning in a patient with selective infarction of the left basal ganglia: evidence for decreased non-routine response selection and performance.Focal damage to the basal ganglia is relatively rare, and little is known about the cognitive effects of damage to specific basal ganglia structures. A 28-year-old, highly educated male (patient RI) sustained a unilateral left ischemic infarction involving primarily the putamen and secondarily the head of the caudate and the anterior internal capsule. Two detailed neuropsychological assessments, at 3 and 16 months post-infarction, revealed that a majority of cognitive abilities were spared. RI's general intelligence, simple attention, concept formation, cognitive flexibility, and explicit memory were unaffected. Select cognitive abilities were affected, and these appeared to be related to direct involvement of the putamen and/or to indirect disruption of circuits between the basal ganglia and frontal lobes. Consistent with involvement of the left putamen, RI showed micrographia with his right hand. Interestingly, his micrographia was context-dependent, appearing only when verbal expression was involved (e.g., present when writing spontaneously, but not when copying sentences or when drawing). Evidence of disruption to frontal systems included variably decreased sustained attention, mildly decreased ability to generate words and to generate ideas, and significantly impaired abstraction ability in both verbal and visual modalities. Although there are several possible interpretations for these findings, this pattern of cognitive and motor functioning is consistent with neuroimaging research suggesting that the frontal/subcortical circuit between the putamen and frontal motor areas plays a role in non-routine response selection and performance.- - - - - - - - - - ranking = 6.2763623607586E-6keywords = hand (Clic here for more details about this article) |
6/9. Ipsilateral hemiparesis caused by a corona radiata infarct after a previous stroke on the opposite side.Ipsilateral hemiparesis after a supratentorial stroke is rare. However, the role of the reorganization of the unaffected hemisphere in recovery after a stroke is poorly understood. Two patients developed ipsilateral hemiparesis after a left corona radiata infarct. Both of these patients had previously experienced contralateral hemiparesis after a right-sided supratentorial stroke. Functional magnetic resonance imaging demonstrated bilateral motor area activation during paretic left hand movement. This finding suggests that the ipsilateral hemiparesis was caused by a new stroke in the ipsilateral motor system that was functionally reorganized after the previous stroke.- - - - - - - - - - ranking = 6.2763623607586E-6keywords = hand (Clic here for more details about this article) |
7/9. motor cortex excitability after thalamic infarction.transcranial magnetic stimulation was used to map hand muscle representations in the motor cortex of a patient in whom infarction of the sensory thalamus deprived the sensorimotor cortex of sensory input. The threshold for activation of the motor cortex on the affected side was higher and the cortical representational maps of individual muscles were less well defined than those on the normal side. It is concluded that electrophysiological changes in cortical organisation can be demonstrated following withdrawal of, or imbalance in sensory afferent activity to the cerebral cortex in humans.- - - - - - - - - - ranking = 6.2763623607586E-6keywords = hand (Clic here for more details about this article) |
8/9. Novel representation of astasia associated with posterior cingulate infarction.BACKGROUND AND PURPOSE: The representation elicited in the cingulate motor area has been demonstrated in animals, but remains unclear in humans. In particular, the representation and pathogenic mechanisms of the posterior cingulate cortex are poorly understood, especially in humans. We describe a case of posterior cingulate infarction associated with contralateral astasia. CASE DESCRIPTION: A 67-year-old right-handed man with a 10-year history of hypertension suddenly presented with right-sided pulsion on attempting to stand or sit. On the following day, he could not maintain a sitting position. The patient immediately fell to the floor because of instability, characterized by marked right-sided pulsion despite no muscle weakness, sensorial deficits, or cerebellar ataxia. Magnetic resolution imaging of the brain showed abnormal intensity in the posterior parts of the cingulate, with no other clinically significant lesions. CONCLUSIONS: Because the cingulate motor area is connected to the vestibulocerebellar system through the thalamic nuclei, disruption of this connection by posterior cingulate infarction may result in astasia.- - - - - - - - - - ranking = 6.2763623607586E-6keywords = hand (Clic here for more details about this article) |
9/9. Peri-infarct reorganization in a patient with corona radiata infarct: a combined study of functional MRI and diffusion tensor image tractography.PURPOSE: We investigated the motor recovery mechanism of a stroke patient using functional MRI (fMRI) and diffusion tensor image tractography (DTT). methods: A 60 year-old woman with right corona radiata infarct presented with complete paralysis of the left upper extremity. The motor function of the affected upper extremity recovered slowly for 6 months to a point of nearly normal function. The motor function of the patient was evaluated by fMRI and DTT at 6 months from the onset. FMRI was performed at 1.5 T with timed hand grasp-release movements. DTT was performed using 1.5 T with a synergy-L Sensitivity Encoding head coil. Three dimensional reconstructions of the fiber tracts were obtained with FA < 0.3, angle > 45 degrees as termination criteria. RESULTS: The contralateral primary sensorimotor cortex (SM1) was activated during both affected (left) and unaffected hand movements. DTT showed that the tracts originated from either SM1; the tracts then descended along the known pathway of the corticospinal tract, with the exception that the tract of the affected (right) hemisphere descended along the posterior portion of the infarcted corona radiata. CONCLUSIONS: It seems that the motor function of the affected upper extremity was reorganized to the posterior portion of the infarcted corona radiata. This finding may reflect functional reorganization of the motor pathway following corticospinal tract damage. This appears to be one motor recovery mechanism of subcortical infarct.- - - - - - - - - - ranking = 1.2552724721517E-5keywords = hand (Clic here for more details about this article) |