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At least 19 recordsLinked to original sources

Left caloric vestibular stimulation ameliorates right hemianesthesia.

BACKGROUND: Left caloric vestibular stimulation (CVS) transiently reduces impairments of right-brain-damaged patients with left unilateral neglect, including left hemianesthesia, contralateral to the side of the lesion (contralesional). Conversely, no effect on right contralesional hemianesthesia in left-brain-damaged patients is seen with right CVS. This discrepancy is unexplained. METHODS: The authors explored the effect of CVS on right- and left-brain-damaged patients with hemianesthesia. One left-brain-damaged patient had an fMRI study during tactile stimulation before and after left CVS. The same fMRI touch study, without CVS, was performed in neurologically unimpaired subjects. RESULTS: A transient remission of right hemianesthesia associated with left brain damage was observed, provided that cold CVS was administered to the left ear. In the left-brain-damaged patient studied with fMRI, left CVS modulated the neural response to right hand tactile stimuli of a portion of the secondary somatosensory area (SII) of the right hemisphere. In neurologically unimpaired subjects, fMRI scans showed that the same part of area SII in the right hemisphere was activated by ipsilateral right-sided touches and to a larger extent than area SII in the left hemisphere by left-sided touches. CONCLUSIONS: Left caloric vestibular stimulation is effective on both left and right hemianesthesia because it modulates the hemisphere that has a more complete representation of, or is capable to attend to, the whole somatosensory surface of the body. These results suggest a hardwired hemispheric asymmetry in hand representation, starting from a somatotopically organized brain region such as area SII.

Adult↗

Hemianesthesia and aphasia. An anatomical and behavioral study.

A 61-year-old right-handed man with a history of lacunar cerebrovascular disease and hypertension had the sudden onset of right-sided numbness and difficulty speaking. Neurologic evaluation revealed a dense right hemianesthesia that included the face, trunk, arm, and leg. Neuropsychological examination documented a conduction aphasia, which resolved nearly completely several months later. Computed tomographic and magnetic resonance imaging studies showed a lesion in the left hemisphere that involved the posterior insula and disrupted thalamocortical connections but entirely spared the thalamus proper. We suggest that the combination of hemianesthesia and aphasia indicates a white matter lesion subjacent to inferior parietal and posterior temporal cortices.

Aphasia↗

Hemianopia, hemianesthesia, and spatial neglect: a study with evoked potentials.

We recorded somatosensory or visual evoked potentials (SEPs, VEPs) to stimuli contralateral and ipsilateral to the lesion in three right-brain-damaged patients with left spatial hemineglect and in three left-brain-damaged patients without evidence of neglect, as assessed by visual exploratory tasks. All patients had contralateral homonymous hemianopia or hemianesthesia. The three neglect patients showed normal SEPs or VEPs to stimuli delivered to the left half-field or to the left hand, without conscious perception and verbal report of the stimulation. By contrast, the three left-brain-damaged patients without neglect showed no recognizable cortical evoked response to contralateral visual or somatosensory stimuli. In all patients, the cortical evoked responses to ipsilateral stimulation were normal. In patients with spatial hemineglect, hemianopia and hemianesthesia may be manifestations of the neglect syndrome (visual and somatosensory hemi-inattention), rather than representing primary sensory deficit. Visual and somatosensory hemi-inattention may be due to defective access to the neural processes subserving conscious perception by information that has undergone early sensory processing.

Aged↗

Hemianesthesia, sensory neglect, and defective access to conscious experience.

We report a patient with an ischemic stroke in the vascular territory of the right middle cerebral artery who had left spatial neglect and left hemianesthesia. The patient showed a dissociation between defective verbal reporting of somatosensory stimuli delivered to the left hand and physiologic evidence from an autonomic index. This indicates that there was processing of undetected stimuli without the patient's awareness, and suggests that the hemianesthesia was due, at least in part, to somesthetic hemi-inattention.

Cerebral Angiography↗

Temporary remission of left hemianesthesia after vestibular stimulation. A sensory neglect phenomenon.

In three right-brain damaged patients with contralesional neglect vestibular stimulation induced a temporary remission of left hemianesthesia, in addition to the well-known transient recovery of extrapersonal and personal neglect. These findings indicate that in neglect patients attentional factors may play an important role in producing apparently "primary" sensory deficits, which may be interpreted in terms of defective access to conscious processing.

Aged↗

Conversion disorder presenting as hemiplegia and hemianesthesia with loss of neurologic reflexes: a case report.

Conversion disorders can present with a variety of sensorimotor signs and symptoms. We present the case of a young woman who presented with sudden onset hemiplegia and hemianesthesia including unilateral loss of deep tendon reflexes, Babinski reflex, and loss of rectal tone with bladder incontinence. The loss of rectal tone, loss of deep tendon reflexes, and a flaccid Babinski reflex are unusual signs in conversion disorders. A thorough medical workup including x-rays, CT scans, and magnetic resonance imaging revealed no organic causes for the neurologic deficits. Before the onset of symptoms, the patient was emotionally upset during an argument, which may have provided the psychologic stressor necessary for a conversion disorder. The young woman gradually regained full neurologic function over the next 14 hours. Conversion disorders should be considered when the neurologic findings do not correspond to known anatomic or physiologic pathways, although a thorough medical investigation must be performed to search for organic causes.

Adult↗

Covert processing of information in hemianesthesia: a case report.

A 69-year-old patient with a cortical lesion of the primary sensory area showed a surprising sensorimotor control of the anesthetized arm. This observation suggested the existence of residual capacities of somesthetic information processing. This hypothesis was tested using a forced choice procedure on four tasks involving discrimination between different characteristics of the tactual-kinaesthetic stimulus. Whereas the patient was unable to identify the direction of movement or to discriminate between different letters, she could detect the occurrence of the stimulation or its dynamic quality significantly well. These results are discussed in reference to an anatomo-functional organization analogous to the one underlying the processing of visual information.

Aged↗

Modulation of neglect hemianesthesia by transcutaneous electrical stimulation.

The effects of transcutaneous electrical stimulation on deficits of tactile perception contralateral to a hemispheric lesion were investigated in 10 right brain-damaged patients and in four left brain-damaged patients. The somatosensory deficit recovered, transiently and in part, after stimulation of the side of the neck contralateral to the side of the lesion, in all 10 patients with lesions in the right hemisphere, both with (six cases) and without (four cases) left visuo-spatial hemineglect, and in one left brain-damaged patient with right hemineglect. In three left brain-damaged patients without hemineglect, the treatment had no detectable effects. In one right brain-damaged patient, the stimulation of the side of the neck ipsilateral to the side of the lesion temporarily worsened the somatosensory deficit. These effects of transcutaneous electrical stimulation are similar to those of vestibular stimulation. The suggestion is made that these treatments modulate, through afferent sensory pathways, higher-order spatial representations of the body, which are pathologically distorted toward the side of the lesion. The modulatory effect is direction-specific: the defective internal representation of the contralesional side may be either partly restored, improving the disorder of tactile perception, or further impoverished, worsening the deficit. The possible neural basis of this modulation is discussed.

Adult↗

[Neurophysiologic study of 2 cases of hemianesthesia as a result of subcortical lesions. Results of recording far-field somatosensory evoked potentials].

The volume-conducted responses of the lemniscal pathways to median nerve stimulation at wrist may be recorded on the scalp (far-field potentials). These positive far-field SEPs components are widely distributed on the scalp and their peaking latencies vary between 9 and 15 milliseconds. In normal adults a maximum of 4 far-field potentials (P9, P11, P13 and P14) may be individualized; two of them (P9 and P14) are constant. These SEPs were studied in two patients with lateralized somatosensory loss; one with a cervico-medullary traumatic lesion, the other with a thalamic infarct. These observations allow the following conclusions 1) the P9 component takes origin in the proximal part of the brachial plexus roots; 2) the P14 potential has a brainstem origin; 3) the contralateral N20 potential is generated in (or close to) the primary somato-sensory cortex (SI). Thus it is possible with a single channel to record the activity of the somatosensory pathways from dorsal roots up the parietal cortex.

Adult↗

Delayed-onset cerebral arterial gas embolism in a commercial airline mechanic.

A commercial airline mechanic was evaluated for right-sided hemianesthesia. Thorough diagnostic testing failed to identify a definitive etiology, and the mechanic was assessed as having symptoms of a left internal capsule lesion, likely from an ischemic event. On day 12 after symptom onset, he consulted a diving medicine specialist for clearance to continue recreational scuba diving. A thorough history revealed that the patient worked regularly in a compressed air environment of commercial aircraft and had experienced a rapid decompression approximately 48 h prior to onset of the hemianesthesia. The specialist considered pulmonary barotrauma-induced cerebral arterial gas embolism as a possible diagnosis. On day 13 he was treated with hyperbaric oxygen using Treatment Table VI, which produced immediate relief. Following three additional hyperbaric oxygen treatments in the next 11 d, he reported nearly total resolution of his symptoms. This occurrence is believed to be the second report of a cerebral arterial gas embolism in an aircraft mechanic or maintenance crewman and suggests that the latency between time of depressurization and the development of symptoms from a pulmonary barotrauma-induced cerebral arterial gas embolism may extend longer than previously believed.

Adult↗

[The thalamic syndrome of Déjérine-Roussy. Prolegomenon].

Predicted by Dejerine and Long in 1898 and formally described by Dejerine and Roussy in 1906, the "thalamic syndrome" corrected the wrong hypothesis of a capsular "sensory cross roads" suggested by Charcot after 1873 and supported in France during 25 years. Both established the "persistent frank organic hemianesthesia" (sensory-sensitive for Charcot, pure sensitive for Dejerine), namely that a sensory deficit, still severe after regression of the early hemiplegia, could be due to focal brain damage. At that time such a clinical concept was hardly acceptable because it opposed the classic greek philosophical idea that sensation and movement should not be separated. Moreover, intelligence was at that time looked as a four-stage process including sensation, imagination, intellect and memory. The very first step began with the "sensus communis", an anteroom-like where all the sensations simultaneously perceived were coordinated to ensure mind unity. This "sensus communis" was given many subcortical seats during the following centuries, such as the trigone (Herophilus), the ventricles (Founders of the Church, Soemmering), the pineal body (Descartes), the striate bodies (Willis) and, finally, the thalamus (Todd and Carpenter's "English theory"). The description by Meynert in 1871 of a transcapsular direct "sensory bundle" and the cases reported by Türck in 1859 of a sensory-sensitive hemianesthesia after a posterior capsular lesion (in fact, thalamo-capsulostriate) led Charcot to develop his theory after 1873. Owing to the new staining methods of Weigert and Marchi introduced around 1885, Dejerine showed in 1895 the route of the medial lemniscus and his arrival in the thalamus, which led him to postulate in 1898 a "thalamic syndrome" and later to demonstrate it.

England↗

Thalamic pain syndrome of Dejérine-Roussy. Differentiation of four subtypes assisted by somatosensory evoked potentials data.

In 30 patients with a thalamic vascular lesion and clinical somatosensory disturbances in the opposite hemibody without hemiplegia, four nosological groups were identified: group 1 had no central pain but complete hemianesthesia and loss of cortical somatosensory evoked potentials (SEPs) on the affected side (analgic thalamic syndrome). Group 2 had central pain, severe hypoesthesia, and loss of cortical SEPs. Group 3 had central pain and hypoesthesia, with cortical SEPs present, although reduced or delayed on the affected side. Group 4 had central pain with preserved touch and joint sensations and normal SEPs (pure algetic thalamic syndrome). Clinical signs and SEP titration of the actual involvement of lemniscal pathways in these four groups of patients with thalamic syndrome are discussed in relation to current pathophysiology of central pain.

Adult↗