Loss of sensory discrimination after median nerve injury and activation in the primary somatosensory cortex on functional magnetic resonance imaging

2003 ◽  
Vol 99 (1) ◽  
pp. 100-105 ◽  
Author(s):  
Thomas Hansson ◽  
Tom Brismar
Keyword(s):  
Magnetic Resonance ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Nerve Injury ◽  
Tactile Stimulation ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Sensory Discrimination ◽  
Median Nerve Injury ◽  
Fine Print

Object. The aim of this study was to assess the effects of median nerve injury and regeneration on neuronal activation in the somatosensory cortex by means of functional magnetic resonance (fMR) imaging and somatosensory evoked potentials (SSEPs). Methods. Ten injured male patients (mean age 26 years) were examined 15 to 58 months after a total transection of the median nerve at the wrist that was repaired with epineural sutures. Two-point discrimination was lost in Digit II–III and sensory nerve conduction displayed decreased velocity (−29%) and amplitude (−84%) in the median nerve at the wrist. The fMR images were obtained during tactile stimulation (gentle strokes) performed separately on the volar surface of either Digit II–III or Digit IV–V (eight patients: two were excluded because of movement artifacts). The SSEPs were obtained using electrical stimulation proximal to the median nerve lesion. Conclusions. Patients with loss of sensory discrimination after median nerve damage and regeneration had larger areas of activation in fMR imaging near the contralateral central sulcus during tactile stimulation of the injured compared with the noninjured hand. The increase relative to the unaffected hand was 43% (p < 0.02) for Digit II–III stimulation and 46% (p < 0.02) for Digit IV–V stimulation. The SSEP data showed normal latency and amplitude. The enlarged area of cortical activation may be the result of reorganization, and it may indicate that larger cortical areas are involved in the discriminatory task after a derangement of the peripheral input.

Functional magnetic resonance imaging of somatosensory cortex activity produced by electrical stimulation of the median nerve or tactile stimulation of the index finger

2000 ◽  
Vol 93 (5) ◽  
pp. 774-783 ◽  
Author(s):  
Maxwell Boakye ◽  
Sean C. Huckins ◽  
Nikolaus M. Szeverenyi ◽  
Bobby I. Taskey ◽  
Charles J. Hodge
Keyword(s):  
Electrical Stimulation ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Tactile Stimulation ◽  
Index Finger ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
The Right ◽  
Fine Print ◽  
Stimulation Of

Object. Functional magnetic resonance (fMR) imaging was used to determine patterns of cerebral blood flow changes in the somatosensory cortex that result from median nerve stimulation (MNS).Methods. Ten healthy volunteers underwent stimulation of the right median nerve at frequencies of 5.1 Hz (five volunteers) and 50 Hz (five volunteers). The left median nerve was stimulated at frequencies of 5.1 Hz (two volunteers) and 50 Hz (five volunteers). Tactile stimulation (with a soft brush) of the right index finger was also applied (three volunteers). Functional MR imaging data were transformed into Talairach space coordinates and averaged by group. Results showed significant activation (p < 0.001) in the following regions: primary sensorimotor cortex (SMI), secondary somatosensory cortex (SII), parietal operculum, insula, frontal cortex, supplementary motor area, and posterior parietal cortices (Brodmann's Areas 7 and 40). Further analysis revealed no statistically significant difference (p > 0.05) between volumes of cortical activation in the SMI or SII resulting from electrical stimuli at 5.1 Hz and 50 Hz. There existed no significant differences (p > 0.05) in cortical activity in either the SMI or SII resulting from either left- or right-sided MNS. With the exception of the frontal cortex, areas of cortical activity in response to tactile stimulation were anatomically identical to those regions activated by electrical stimulation. In the SMI and SII, activation resulting from tactile stimulation was not significantly different (p > 0.05) from that resulting from electrical stimulation.Conclusions. Electrical stimulation of the median nerve is a reproducible and effective means of activating multiple somatosensory cortical areas, and fMR imaging can be used to investigate the complex network that exists between these areas.

Thalamic stimulation and functional magnetic resonance imaging: localization of cortical and subcortical activation with implanted electrodes

1999 ◽  
Vol 90 (3) ◽  
pp. 583-590 ◽  
Author(s):  
Ali R. Rezai ◽  
Andres M. Lozano ◽  
Adrian P. Crawley ◽  
Michael L. G. Joy ◽  
Karen D. Davis ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Somatosensory Cortex ◽  
Clinical Effects ◽  
Functional Magnetic Resonance ◽  
Electrode Implantation ◽  
Content Type ◽  
Functional Mr Imaging ◽  
Fine Print ◽  
Deep Brain

✓ The utility of functional magnetic resonance (fMR) imaging in patients with implanted thalamic electrodes has not yet been determined. The aim of this study was to establish the safety of performing fMR imaging in patients with thalamic deep brain stimulators and to determine the value of fMR imaging in detecting cortical and subcortical activity during stimulation.Functional MR imaging was performed in three patients suffering from chronic pain and two patients with essential tremor. Two of the three patients with pain had undergone electrode implantation in the thalamic sensory ventralis caudalis (Vc) nucleus and the other had undergone electrode implantation in both the Vc and the periventricular gray (PVG) matter. Patients with tremor underwent electrode implantation in the ventralis intermedius (Vim) nucleus. Functional MR imaging was performed during stimulation by using a pulse generator connected to a transcutaneous extension lead. Clinically, Vc stimulation evoked paresthesias in the contralateral body, PVG stimulation evoked a sensation of diffuse internal body warmth, and Vim stimulation caused tremor arrest.Functional images were acquired using a 1.5-tesla MR imaging system. The Vc stimulation at intensities provoking paresthesias resulted in activation of the primary somatosensory cortex (SI). Stimulation at subthreshold intensities failed to activate the SI. Additional stimulation-coupled activation was observed in the thalamus, the secondary somatosensory cortex (SII), and the insula. In contrast, stimulation of the PVG electrode did not evoke paresthesias or activate the SI, but resulted in medial thalamic and cingulate cortex activation. Stimulation in the Vim resulted in thalamic, basal ganglia, and SI activation.An evaluation of the safety of the procedure indicated that significant current could be induced within the electrode if a faulty connecting cable (defective insulation) came in contact with the patient. Simple precautions, such as inspection of wires for fraying and prevention of their contact with the patient, enabled the procedure to be conducted safely. Clinical safety was further corroborated by performing 86 MR studies in patients in whom electrodes had been implanted with no adverse clinical effects.This is the first report of the use of fMR imaging during stimulation with implanted thalamic electrodes. The authors' findings demonstrate that fMR imaging can safely detect the activation of cortical and subcortical neuronal pathways during stimulation and that stimulation does not interfere with imaging. This approach offers great potential for understanding the mechanisms of action of deep brain stimulation and those underlying pain and tremor generation.

scholarly journals Proximal Median Neuropathy Following Anterior Shoulder Dislocation: The Use of Magnetic Resonance Neurography

2020 ◽  
Vol 11 (1) ◽  
pp. 75-79
Author(s):  
Matthew Silsby ◽  
Alasdair Robertson ◽  
Con Yiannikas
Keyword(s):  
Differential Diagnosis ◽  
Magnetic Resonance ◽  
Median Nerve ◽  
Nerve Injury ◽  
Shoulder Dislocation ◽  
Peripheral Nerve Injury ◽  
Anterior Shoulder Dislocation ◽  
Magnetic Resonance Neurography ◽  
Median Nerve Injury ◽  
Median Neuropathy

Proximal median nerve injury is an uncommon consequence of anterior shoulder dislocation, especially occurring in isolation of other upper limb peripheral nerve injury. We report the case of an 82-year-old woman with a median nerve injury as detected by clinical and neurophysiological examination following a fall and anterior shoulder dislocation. Magnetic resonance neurography confirmed the diagnosis, but also detected asymptomatic brachial plexus and ulnar nerve involvement. Management was non-operative and there has been some improvement over several months. Our case expands the differential diagnosis for proximal median neuropathy and discusses the utility of neurography in cases of neural injury.

Sources of error in comparing functional magnetic resonance imaging and invasive electrophysiological recordings

2000 ◽  
Vol 93 (2) ◽  
pp. 214-223 ◽  
Author(s):  
Derek L. G. Hill ◽  
Andrew D. Castellano Smith ◽  
Andrew Simmons ◽  
Calvin R. Maurer ◽  
Timothy C. S. Cox ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Healthy Volunteers ◽  
Hand Movement ◽  
Epileptogenic Zone ◽  
Imaging Data ◽  
Functional Magnetic Resonance ◽  
Reliable Technique ◽  
Content Type ◽  
The Brain ◽  
Fine Print

Object. Several authors have recently reported studies in which they aim to validate functional magnetic resonance (fMR) imaging against the accepted gold standard of invasive electrophysiological monitoring. The authors have conducted a similar study, and in this paper they identify and quantify two characteristics of these data that can make such a comparison problematic.Methods. Eight patients in whom surgery for epilepsy was performed and five healthy volunteers underwent fMR imaging to localize the part of the sensorimotor cortex responsible for hand movement. In the patient group subdural electrode mats were subsequently implanted to identify eloquent regions of the brain and the epileptogenic zone. The fMR imaging data were processed to correct for motion during the study and then registered with a postimplantation computerized tomography (CT) scan on which the electrodes were visible. The motion during imaging in the two groups studied, and the deformation of the brain between the preoperative images and postoperative scans were measured.The patients who underwent epilepsy surgery moved significantly more during fMR imaging experiments than healthy volunteers performing the same motor task. This motion had a particularly increased out-of-plane component and was significantly more correlated with the stimulus than in the volunteers. This motion was especially increased when the patients were performing a task on the side affected by the lesion. The additional motion is hard to correct and substantially degrades the quality of the resulting fMR images, making it a much less reliable technique for use in these patients than in others. Also, the authors found that after electrode implantation, the brain surface can shift more than 10 mm relative to the skull compared with its preoperative location, substantially degrading the accuracy of the comparison of electrophysiological measurements made in the deformed brain and fMR studies obtained preoperatively.Conclusions. These two findings indicate that studies of this sort are currently of limited use for validating fMR imaging and should be interpreted with care. Additional image analysis research is necessary to solve the problems caused by patients' motion and brain deformation.

Clinical application of functional magnetic resonance imaging in presurgical identification of the central sulcus

1998 ◽  
Vol 88 (5) ◽  
pp. 863-869 ◽  
Author(s):  
Jesús Pujol ◽  
Gerardo Conesa ◽  
Joan Deus ◽  
Luis López-Obarrio ◽  
Fabián Isamat ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Three Dimensional ◽  
Functional Magnetic Resonance ◽  
Central Sulcus ◽  
Clinical Context ◽  
Content Type ◽  
Sensorimotor Region ◽  
Specific Factors ◽  
Eloquent Cortex ◽  
Fine Print

Object. The authors sought to evaluate the advantages and limitations of functional magnetic resonance (fMR) imaging when it was used regularly in the clinical context to identify the central sulcus. Methods. A 1.5-tesla MR system comprising a spoiled gradient recalled acquisition in the steady-state functional sequence and a cross-hand cancellation analysis method were used to evaluate 50 surgical candidates with centrally located space-occupying lesions in the brain. Three-dimensional (3-D) models of the patient's head and brain showing the relative position of the tumor and the eloquent cortex were obtained in each case. A selective and reproducible focal activation was found, indicating the probable central sulcus position in 41 patients (82%). Direct cortical stimulation confirmed the fMR findings in 100% of 22 intraoperatively assessed patients. Failure to identify the central sulcus occurred in 18% of cases and was mainly a consequence of intrinsic damage in the primary sensorimotor region that resulted in severe hand paresis. Conclusions. Although specific factors were identified that contributed to reduced sensitivity of fMR imaging in the clinical context, the present study supports functional assessment and 3-D representation of specific surgical situations as generally feasible in common practice.

Discordance between functional magnetic resonance imaging during silent speech tasks and intraoperative speech arrest

2005 ◽  
Vol 103 (2) ◽  
pp. 267-274 ◽  
Author(s):  
Nicole Petrovich ◽  
Andrei I. Holodny ◽  
Viviane Tabar ◽  
Denise D. Correa ◽  
Joy Hirsch ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Inferior Frontal Gyrus ◽  
Hemispheric Dominance ◽  
Cortical Mapping ◽  
Precentral Gyrus ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Neurosurgical Planning ◽  
Silent Speech ◽  
Fine Print

Object. The goal of this study was to investigate discordance between the location of speech arrest during awake cortical mapping, a common intraoperative indicator of hemispheric dominance, and silent speech functional magnetic resonance (fMR) imaging maps of frontal language function. Methods. Twenty-one cases were reviewed retrospectively. Images of silent speech fMR imaging activation were coregistered to anatomical MR images obtained for neuronavigation. These were compared with the intraoperative cortical photographs and the behavioral results of electrocorticography during awake craniotomy. An fMR imaging control study of three healthy volunteers was then conducted to characterize the differences between silent and vocalized speech fMR imaging protocols used for neurosurgical planning. Conclusions. Results of fMR imaging showed consistent and predominant activation of the inferior frontal gyrus (IFG) during silent speech tasks. During intraoperative mapping, however, 16 patients arrested in the precentral gyrus (PRG), well posterior to the fMR imaging activity. Of those 16, 14 arrested only in the PRG and not in the IFG as silent speech fMR imaging predicted. The control fMR imaging study showed that vocalized speech fMR imaging shifts the location of the fMR imaging prediction to include the motor strip and may be more appropriate for neurosurgical planning.

Localization of human frontal eye fields: anatomical and functional findings of functional magnetic resonance imaging and intracerebral electrical stimulation

2001 ◽  
Vol 95 (5) ◽  
pp. 804-815 ◽  
Author(s):  
Elie Lobel ◽  
Philippe Kahane ◽  
Ute Leonards ◽  
Marie-Hélène Grosbras ◽  
Stéphane Lehéricy ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Magnetic Resonance ◽  
3 Tesla ◽  
Frontal Eye Fields ◽  
Precentral Gyrus ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Cortical Areas ◽  
Fine Print

Object. The goal of this study was to investigate the anatomical localization and functional role of human frontal eye fields (FEFs) by comparing findings from two independently conducted studies. Methods. In the first study, 3-tesla functional magnetic resonance (fMR) imaging was performed in 14 healthy volunteers divided into two groups: the first group executed self-paced voluntary saccades in complete darkness and the second group repeated newly learned or familiar sequences of saccades. In the second study, intracerebral electrical stimulation (IES) was performed in 38 patients with epilepsy prior to surgery, and frontal regions where stimulation induced versive eye movements were identified. These studies showed that two distinct oculomotor areas (OMAs) could be individualized in the region classically corresponding to the FEFs. One OMA was consistently located at the intersection of the superior frontal sulcus with the fundus of the superior portion of the precentral sulcus, and was the OMA in which saccadic eye movements could be the most easily elicited by electrical stimulation. The second OMA was located more laterally, close to the surface of the precentral gyrus. The fMR imaging study and the IES study demonstrated anatomical and stereotactic agreement in the identification of these cortical areas. Conclusions. These findings indicate that infracentimetric localization of cortical areas can be achieved by measuring the vascular signal with the aid of 3-tesla fMR imaging and that neuroimaging and electrophysiological recording can be used together to obtain a better understanding of the human cortical functional anatomy.

Functional magnetic resonance imaging of sensory and motor cortex: comparison with electrophysiological localization

1995 ◽  
Vol 83 (2) ◽  
pp. 262-270 ◽  
Author(s):  
Aina Puce ◽  
R. Todd Constable ◽  
Marie L. Luby ◽  
Gregory McCarthy ◽  
Anna C. Nobre ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Magnetic Resonance ◽  
Motor Cortex ◽  
Mr Imaging ◽  
Sensorimotor Cortex ◽  
Functional Magnetic Resonance ◽  
Planar Imaging ◽  
Content Type ◽  
Functional Mr Imaging ◽  
Fine Print

✓ Functional magnetic resonance (MR) imaging was performed using a 1.5-tesla MR system to localize sensorimotor cortex. Six neurologically normal subjects were studied by means of axial gradient-echo images with a motor task and one or more sensory tasks: 1) electrical stimulation of the median nerve; 2) continuous brushing over the thenar region; and 3) pulsed flow of compressed air over the palm and digits. An increased MR signal was observed in or near the central sulcus, consistent with the location of primary sensory and motor cortex. Four patients were studied using echo planar imaging sequences and motor and sensory tasks. Three patients had focal refractory seizures secondary to a lesion impinging on sensorimotor cortex. Activation seen on functional MR imaging was coextensive with the location of the sensorimotor area determined by evoked potentials and electrical stimulation. Functional MR imaging provides a useful noninvasive method of localization and functional assessment of sensorimotor cortex.

Patterns of lateral sensory cortical activation determined using functional magnetic resonance imaging

1998 ◽  
Vol 89 (5) ◽  
pp. 769-779 ◽  
Author(s):  
Charles J. Hodge ◽  
Sean C. Huckins ◽  
Nikolaus M. Szeverenyi ◽  
Michael M. Fonte ◽  
Jacob G. Dubroff ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Imaging Techniques ◽  
Cortical Activation ◽  
The Other ◽  
Functional Magnetic Resonance ◽  
Cortical Function ◽  
Content Type ◽  
And Cluster Analysis ◽  
Student’S T ◽  
Fine Print

Object. Functional magnetic resonance (fMR) imaging was performed in human volunteers to determine the lateral perisylvian cortical areas activated by innocuous cutaneous stimulation. Methods. Eight volunteers who underwent 53 separate experiments form the basis of this report. Eight contiguous coronal slices were obtained using echoplanar fMR imaging techniques while participants were at rest and while somatosensory activation stimuli consisting of vibration or air puffs were delivered to various body areas. The data were analyzed using Student's t-test and cluster analysis to determine significant differences between the resting and activated states. The findings were as follows: the areas in the lateral cortex activated by the sitmuli were the primary sensory cortex (SI), the second somatosensory area (SII), the insula, the superior parietal lobule, and the retroinsular parietal operculum (RIPO). Somatotopy was demonstrable in SI but not in the other areas identified. There was a surprisingly low correlation between the amount of cortex activated in the various areas, which could mean separate inputs and functions for the areas identified. The highest correlation was found between activity in SII and RIPO (0.69). Conclusions. The authors maintain that fMR imaging can be used to identify multiple lateral somatosensory areas in humans. Somatotopy is demonstrated in SI but not in the other lateral cortical sensory areas. The correlations between the amounts of cortex activated in the different lateral sensory areas are low. Recognition of the multiple lateral sensory areas is important both for understanding sensory cortical function and for safe interpretation of studies designed to identify the central sulcus by activating SI.

Patterns of functional magnetic resonance imaging activation in association with structural lesions in the rolandic region: a classification system

2001 ◽  
Vol 94 (6) ◽  
pp. 946-954 ◽  
Author(s):  
Alexandre C. Carpentier ◽  
R. Todd Constable ◽  
Michael J. Schlosser ◽  
Alain de Lotbinière ◽  
Joseph M. Piepmeier ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Motor Cortex ◽  
Motor Skills ◽  
Classification Scheme ◽  
Surgical Intervention ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Rolandic Region ◽  
Fine Print

Object. Functional magnetic resonance (fMR) imaging of the motor cortex is a potentially powerful tool in the preoperative planning of surgical procedures in and around the rolandic region. Little is known about the patterns of fMR imaging activation associated with various pathological lesions in that region or their relation to motor skills before surgical intervention. Methods. Twenty-two control volunteers and 44 patients whose pathologies included arteriovenous malformations (AVMs; 16 patients), congenital cortical abnormalities (11 patients), and tumors (17 patients) were studied using fMR imaging and a hand motor task paradigm. Activation maps were constructed for each participant, and changes in position or amplitude of the motor activation on the lesion side were compared with the activation pattern obtained in the contralateral hemisphere. A classification scheme of plasticity (Grades 1–6) based on interhemispheric pixel asymmetry and displacement of activation was used to compare maps between patients, and relative to hand motor dexterity and/or weakness. There was 89.4% interobserver agreement on classification of patterns of fMR imaging activation. Displacement of activation by mass effect was more likely with tumors. Cortical malformations offer a much higher functional reorganization than AVMs or tumors. High-grade plasticity is recruited to compensate for severe motor impairment. Conclusions. Pattern modification of fMR imaging activation can be systematized in a classification of motor cortex plasticity. This classification has shown good correlation among grading, brain lesions, and motor skills. This proposal of a classification scheme, in addition to facilitating data collection and processing from different institutions, is well suited for comparing risks associated with surgical intervention and patterns of functional recovery in relation to preoperative fMR imaging categorization. Such studies are underway at the authors' institution.

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