Infarct of the anterior limb of the right internal capsule causing left motor neglect: case report and cerebral blood flow study

A sixty-nine year old hypertensive man had left motor neglect following an infarct of the anterior limb of the right internal capsule. He also had left auditory extinction on verbal dichotic listening and a sligh constructional apraxia. Regional cerebral blood flow (CBF) was measured at rest with Xenon 133 inhalation and was found to be slightly decreased in a diffuse fashion. Motor activation of the right hand resulted in an increase of CBF in the contralateral superior rolandic area, whereas no such increase was found during motor activation of the left hand. This lack of cortical CBF increase on contralateral motor activation is interpreted as a consequence of the failure of some corticosubcortical connexions involved in motor arousal. The specifically dynamic appearance of regional CBF abnormalities, i.e. during selective activation as opposed to rest measurements, is consistent with the functional character of neglect.     

Functional connectivity between cortical hand motor and language areas during recovery from aphasia

Previous data indicate that in healthy subjects, there is a connectivity between cortical areas for hand movement and language on the left hemisphere. This link is possibly mediated by the so-called mirror neuron system. The present study investigated the functional relationship between linguistic and hand movement processing in patients who were recovering from post-stroke aphasia. The excitability of the right- and left-hand motor cortex during language production in patients who were recovering from post-stroke aphasia and age-matched controls was investigated. As control, phonation was investigated. Hand motor cortex excitability was assessed with Motor Evoked Potentials which were elicited by Transcranial Magnetic Stimulation (TMS). In patients, reading aloud enhanced the excitability of the right hemispheric hand motor cortex, whereas phonation had no effect on hand motor cortex excitability. In the control group, an increased excitability of the left hemispheric hand motor system was found during reading aloud in accordance with previous data. The present data suggest a functional connectivity between regions mediating hand movements and reading. This may indicate that the right hemisphere participates in language processing as far as involved in single word reading in patients recovering from aphasia. The coactivation between cerebral representations of hand movements and language may be used therapeutically for aphasia rehabilitation.     

The groping phenomena in a case of Alzheimer type dementia

We reported a case of senile dementia, Alzheimer type, with groping in response to a visual stimulus ("visual groping"). T.S. was a right-handed woman, 69 years old. In the beginning she displayed "visual groping" of the right hand, besides aphasia, lowered registration and Casteigne's "Motor neglect" of the right upper extremity. As the disease progressed, "visual groping" of the left hand developed, followed by "forced grasping" of the left hand. When the patient was 62 years old, she first showed decreased volition and lowered registration. Later poor finger movement and lessened speech were marked. At the age of 69, she was admitted to our hospital with aphasia and reduced registration. The patient showed preservation in naming and drawing tests. She also displayed a "visual groping" phenomenon of the right hand. This phenomenon was revealed when an examiner displayed something about 50 cm in front of the patient, and then she extended the upper extremity gropingly. We considered this phenomenon as "groping in response to a visual stimulus" of Denny-Brown. At the same time, the motor or praxic disorder of this patient consisted of paucity of movement. When she was told to imitate, her right upper extremity was hardly utilized, although later movements could be realized by her practice. When she was told to pour water from one glass into another, she used her left hand, although she used her right hand for spontaneous actions. So we considered this dyspraxia as a motor neglect of Casteigne.(ABSTRACT TRUNCATED AT 250 WORDS)     

"Alien hand" and loss of bimanual coordination after dominant anterior cerebral artery territory infarction.

Three patients with dominant anterior cerebral artery territory infarction demonstrated a severe disturbance of upper limb motor control with impaired bimanual coordination, the "alien hand" sign, and intermanual conflict, in addition to signs of callosal interruption and a transcortical motor aphasia. Recordings of movement-related potentials in one patient showed an attenuated Bereitschaftspotential and a greater asymmetry of the NS' component of the premotor negativity with left finger than with right finger movement. The impairment of bimanual motor control and associated abnormal motor behaviour of the right hand in these cases are postulated to be due to involvement of the supplementary motor area and related areas of the medial frontal cortex.     

Voluntary activation and cortical activity during a sustained maximal contraction: an fMRI study

Motor fatigue is an exercise-induced reduction in the force-generating capacity. The underlying mechanisms can be separated into factors residing in the periphery or in the central nervous system. We designed an experiment in which we investigated central processes underlying motor fatigue by means of magnetic resonance imaging in combination with the twitch interpolation technique. Subjects performed a sustained maximal abduction (2 min) with the right index finger. Brain activation was recorded with an MR scanner, together with index finger abduction force, EMG of several hand muscles and interpolated twitches. Mean activity per volume was calculated for the primary motor cortex and the secondary motor areas (supplementary motor, premotor, and cingulate areas) as well as mean force and mean rectified EMG amplitude. Results showed a progressive decline in maximal index finger abduction force and EMG of the target muscles combined with an increase in brain activity in the contralateral primary motor cortex and secondary motor areas. Analysis of the twitches superimposed on the sustained contraction revealed that during the contraction the voluntary drive decreased significantly. In conclusion, our data showed that despite an increase in brain activity the voluntary activation decreased. This suggests that, although the CNS increased its input to the relevant motor areas, this increase was insufficient to overcome fatigue-related changes in the voluntary drive.     

Apraxic agraphia with neglect-induced paragraphia

Agraphia may result from the loss or unavailability of the memory of movements necessary to form written letters. For this mechanism to be invoked, it must first be demonstrated that there is no language deficit and that there is no disconnection between language and motor areas. A left-handed patient demonstrated bilateral agraphia and apraxia, but not aphasia, following a right parietal infarction. Preservation of the ability to type with the left hand demonstrated that the right hemisphere was not disconnected from language input. In addition, paragraphic errors while typing were shown to be secondary to left hemispatial neglect.     

Motor neglect of thalamic origin: report on two cases (author's transl)

Two cases of thalamic lesions with motor neglect are presented. The syndrome of motor neglect was complete in those cases with a) underutilization of left limbs, but good utilization upon verbal orders, b) loss of placement reaction, c) weakness of movement when hand was approaching the target, d) weakness of motor reaction to nociceptive stimuli. Those cases confirm that motor neglect exists after thalamic lesions and bring pathologic clues for topographic discussion. Motor neglect seems to be a particular case of partial unilateral neglect throwing some doubt on the hypothesis of a global trouble of hemispheric activation. Prevalence of left motor neglects suggests some linkage between propositional motility and language. One may suppose that in the right hemisphere language is able to have a vicarious action when spontaneous activation is lost; at the opposite, in the left hemisphere language and motility would be too linked to let this dissociation be generally possible.     

Cortical activation during foot movements: II effect of movement rate and side

Cerebral control of foot movements has received limited study. Functional MRI compared slow with rapid foot movement, and right (dominant) with left foot movement. Brain activation during right, as compared with left, foot movement was larger, with higher amplitude task-related motor cortex signal change, and higher laterality index. Brain activation during fast, as compared with slow, foot movement was larger in cortical and cerebellar areas but smaller in deep gray areas. Some principles of cerebral control of hand movement extend to foot, but exceptions found include that dominant foot movement showed greater activation than did nondominant, and faster foot movements activated bilateral deep gray matter structures less than did slower. Results might have utility in trials of restorative therapies.     

The effect of video-guidance on passive movement in patients with cerebral palsy: fMRI study

In patients with cerebral palsy (CP), neuroimaging studies have demonstrated that passive movement and action–observation tasks have in common to share neuronal activation in all or part of areas involved in motor system. Action observation with simultaneous congruent passive movements may have additional effects in the recruitment of brain motor areas. The aim of this functional magnetic resonance imaging (fMRI) study was to examine brain activation in patients with unilateral CP during passive movement with and without simultaneous observation of simple hand movement. Eighteen patients with unilateral CP (fourteen male, mean age 14 years and 2 months) participated in the study. Using fMRI block design, brain activation following passive simple opening–closing hand movement of either the paretic or nonparetic hand with and without simultaneous observation of a similar movement performed by either the left or right hand of an actor was compared. Passive movement of the paretic hand performed simultaneously to the observation of congruent movement activated more “higher motor areas” including contralesional pre-supplementary motor area, superior frontal gyrus (extending to premotor cortex), and superior and inferior parietal regions than nonvideo-guided passive movement of the paretic hand. Passive movement of the paretic hand recruited more ipsilesional sensorimotor areas compared to passive movement of the nonparetic hand. Our study showed that the combination of observation of congruent hand movement simultaneously to passive movement of the paretic hand recruits more motor areas, giving neuronal substrate to propose video-guided passive movement of paretic hand in CP rehabilitation.     

Hand motor cortical area reorganization following cerebral infarction evaluated with functional MRI, near infrared spectroscopic imaging, and transcranial magnetic stimulation]

A 60-year-old, right-handed man suffered from left hemiparesis with upper limb dominance. CT and MRI revealed cerebral infarction of the entire right middle cerebral artery territory. His hemiparesis recovered excellently and residual neurological deficits 6 years later were left hand weakness(grasping power 9 kg vs. 35 kg in the right) and clumsiness. Functional MRI was performed. During right(normal) hand grasping, activation was seen in the left sensorimotor cortex and supplementary motor area. During left(paretic) hand grasping, activation was seen in the left (ipsilateral) sensorimotor cortex, right parietal cortex, and bilateral supplementary motor areas. Near infrared spectroscopic imaging showed similar results. During right hand grasping, left sensorimotor cortex was activated, and during left hand grasping, bilateral sensorimotor cortices were activated with ipsilateral predominance. Transcranial magnetic stimulation of the left motor hand area evoked right hand movement and stimulation of a point near that area evoked ipsilateral left hand muscle movement. Thus, the findings of the three techniques consistently suggest that the recovery of left hemiparesis of this patient was promoted by motor cortical area reorganization including the ipsilateral motor cortex.     

Motor reorganization in multiple sclerosis

OBJECTIVE: To assess intra-hemispheric and interhemispheric reorganization of motor activation in multiple sclerosis (MS). Motor reorganization may contribute to minimizing motor deficits after demyelination in MS. METHODS: We used surface-based analysis to study functional organization for motor function in ten healthy controls and in 15 MS subjects. RESULTS AND DISCUSSION: In MS subjects, activation in the right hemisphere (ipsilateral to the hand moved) was significantly increased compared with control subjects. We interpreted this increase as interhemispheric reorganization of motor activation. The increases in right hemisphere activation were the greatest in the pre-motor cortex (Brodmann area 6) and the cognitive areas. Within the left hemisphere, contralateral to the right hand, total motor activation was not increased and the centroid of activation was not displaced when MS subjects were compared with controls. However, we found that MS subjects with high MS plaque loads showed an anterior shift of the focus of motor activation with right hand movement when compared with the low MS plaque load subjects (p<0.05). Furthermore, there was more activation in pre-motor cortex (Brodmann area 6) in the high plaque load group and less activation in sensory areas (Brodmann areas 1, 2 and 3). CONCLUSION: Functional magnetic resonance imaging (fMRI) provides evidence that both interhemispheric and intra-hemispheric motor reorganization occur in MS.     

Anatomical Functional Changes in a Patient Presenting a Complex Malformation of Cortical Development

The authors describe a case of right fronto‐parietal micropoligyria associated with small schizencephaly clefts and the presence of a frontal open‐lip schizencephaly with corpus callosum agenesis. A functional magnetic resonance imaging (fMRI) study was performed to evaluate the possible reorganization of cortical functions in a patient presentinga complex malformation pattern and to investigate which cortical areas were activated during left finger movements. An fMRI study was performed during the execution of a repetitive index finger‐to‐thumb opposition movement with the right hand and the left hand in 2 separate sessions. Movement of the right hand induced a normal motor activation pattern involving the contralateral left sensory‐motor cortex. Movement of the left hand produced significant activation of brain cortex. This fMRI study highlights the compensatory role of the ipsilateral cortical pathways in hand movements in the case of a complex brain malformation that involves the main motor activation areas.     

Regional cerebral blood flow correlates of aphasia outcome in cerebral hemorrhage and cerebral infarction

The relationship between recovery from aphasia and regional cerebral blood flow (CBF) was compared in 87 patients, 44 with cerebral hemorrhage and 43 with non-embolic cerebral infarction. CBF values correlated poorly with aphasia outcome in patients with cerebral hemorrhage whereas a tight correlation was demonstrated in patients with non-embolic cerebral infarction. A marked variability of CBF values in the acute and subacute stage might account for the poor correlation between CBF and aphasia outcome in patients with cerebral hemorrhage. On the other hand, a sharp discrimination was achieved between those with a good recovery from aphasia and those with a poor recovery by the dimensions of the hematoma on CT. In non-embolic cerebral infarction, a relative frontal ischemia was associated with motor aphasia while a relative temporal ischemia was associated with sensory aphasia. This dichotomy was not demonstrated in the regional CBF values in patients with cerebral hemorrhage.     

Bilateral motor resonance evoked by observation of a one-hand movement: role of the primary motor cortex

In humans, observation of movement performed by others evokes a subliminal motor resonant response, probably mediated by the mirror neurone system, which reproduces the motor commands needed to execute the observed movement with good spatial and temporal fidelity. Motor properties of the resonant response were here investigated with the ultimate goal of understanding the principles operating in the transformation from observation to internal reproduction of movement. Motor resonance was measured as the modulation of excitability of spinal motoneurones, evoked by the observation of a cyclic flexion-extension of one hand. The first two experiments showed that the observation of a one-hand movement always evoked a bimanual resonant response independent of which hand was observed and that these bilateral responses were consistently phase-linked. H-reflexes simultaneously recorded in right and left flexor carpi radialis muscles were always modulated 'in-phase' with each other. The goal of the third experiment was to define the role of primary motor cortex in the bilateral resonant response. Bilateral H-reflexes were recorded during a temporary inactivation induced by transcranial magnetic stimulation over the left cortical hand motor area of observers. The finding that such cortical depression abolished the H-reflex modulation of only the right flexor carpi radialis motoneurones, leaving it unchanged on the left side, suggested that both primary motor areas were activated by the premotor cortex and transmit the resonant activation through crossed corticospinal pathways. The data provide further evidence that the subliminal activation of motor pathways induced by movement observation is organized according to general rules shared with the control of voluntary movement.     

Motor imagery in normal subjects and in asymmetrical Parkinson's disease: a PET study

OBJECTIVE: To investigate, using PET and H2(15)O, brain activation abnormalities of patients with PD during motor imagery. To determine whether motor imagery activation patterns depend on the hand used to complete the task. BACKGROUND: Previous work in PD has shown that bradykinesia is associated with slowness of motor imagery. METHODS: The PET study was performed in eight patients with PD with predominantly right-sided akinesia, and in eight age-matched control subjects, all right-handed. Regional cerebral blood flow was measured by PET and H2(15)O while subjects imagined a predetermined unimanual externally cued sequential movement with a joystick with either the left or the right hand, and during a rest condition. RESULTS: In normal subjects, the prefrontal cortex, supplementary motor area (SMA), superior parietal lobe, inferior frontal gyrus, and cerebellum were activated during motor imagery with either the left or the right hand. Contralateral primary motor cortex activation was noted only when the task was imagined with the right (dominant) hand, whereas activation of the dorsolateral prefrontal cortex was observed only during imagery with the left hand. In patients with PD, motor imagery with the right ("akinetic") hand was characterized by lack of activation of the contralateral primary sensorimotor cortex and the cerebellum, persistent activation of the SMA, and bilateral activation of the superior parietal cortex. Motor imagery with the left ("non-akinetic") hand was also abnormal, with lack of activation of the SMA compared with controls. CONCLUSIONS: In patients with PD with predominantly right-sided akinesia, brain activation during motor imagery is abnormal and may appear even with the less affected hand. In normal subjects, brain activation during motor imagery depends on the hand used in the imagined movement.     

Stable ratio of ipsilateral to contralateral sensory motor cortex activity despite varying effort and peripheral nerve block.

BACKGROUND: Ipsilateral sensory motor cortex (SMC) activation can occur during hand movements following cerebral injury. We studied the effect of increasing task difficulty and temporary peripheral paralysis on patterns of motor system activation.METHODS: Six healthy subjects completed a functional MRI paradigm of right finger abduction with four stages; light resistance, strong resistance, imagined movement and attempted abduction after ulnar nerve blockade. Activation maps compared images acquired during rest and task, while region of interest analysis measured numbers of activated pixels.RESULTS: All subjects showed some ipsilateral SMC activation. Across all subjects and all tasks involving hand movement, contralateral activation was proportional to ipsilateral activation (2.1:1; r=0.86).CONCLUSIONS: The relationship between ipsilateral and contralateral SMC activation remained stable despite differing effort or hand paralysis. The contralateral and ipsilateral SMC appear to act in a coordinated fashion during unilateral hand movements.     

Motor representation in patients rapidly recovering after stroke: a functional magnetic resonance imaging and transcranial magnetic stimulation study

OBJECTIVE: Neuroimaging studies have suggested an evolution of the brain activation pattern in the course of motor recovery after stroke. Initially poor motor performance is correlated with an recruitment of the uninjured hemisphere that continuously vanished until a nearly normal (contralateral) activation pattern is achieved and motor performance is good. Here we were interested in the early brain activation pattern in patients who showed a good and rapid recovery after stroke. METHODS: Ten patients with first-ever ischemic stroke affecting motor areas had to perform self-paced simple or more complex movements with the affected or the unaffected hand during functional magnetic resonance imaging (fMRI). The location and number of activated voxels above threshold were determined. To study possible changes in the cortical motor output map the amplitude of the motor evoked potentials (MEP) and the extent of the excitable area were determined using transcranial magnetic stimulation (TMS). RESULTS: The pattern of activation observed with movements of the affected and the unaffected hand was similar. In the simple motor task significant (P<0.05) increases were found in the primary motor cortex ipsilateral to the movement, the supplementary motor area and the cerebellar hemisphere contralateral to the movement during performance with the affected hand compared to movements with the unaffected hand. When comparing simple with more complex movements performed with either the affected or the unaffected hand, a further tendency to increased activation in motor areas was observed. The amplitude of MEPs obtained from the affected hemisphere was smaller and the extent of cortical output maps was decreased compared to the unaffected hemisphere; but none of the patients showed MEPs at the affected hand when the ipsilateral unaffected motor cortex was stimulated. CONCLUSIONS: Despite a rapid and nearly complete motor recovery the brain activation pattern was associated with increased activity in (bilateral) motor areas as revealed with fMRI. TMS revealed impaired motor output properties, but failed to demonstrate ipsilateral motor pathways. Successful recovery in our patients may therefore rely on the increased bilateral activation of existing motor networks spared by the injury.     

Dorsal premotor activity and connectivity relate to action selection performance after stroke

Compensatory activation in dorsal premotor cortex (PMd) during movement execution has often been reported after stroke. However, the role of PMd in the planning of skilled movement after stroke has not been well studied. The current study investigated the behavioral and neural response to the addition of action selection (AS) demands, a motor planning process that engages PMd in controls, to movement after stroke. Ten individuals with chronic, left hemisphere stroke and 16 age‐matched controls made a joystick movement with the right hand under two conditions. In the AS condition, participants moved right or left based on an abstract, visual rule; in the execution only condition, participants moved in the same direction on every trial. Despite a similar behavioral response to the AS condition (increase in reaction time), brain activation differed between the two groups: the control group showed increased activation in left inferior parietal lobule (IPL) while the stroke group showed increased activation in several right/contralesional regions including right IPL. Variability in behavioral performance between participants was significantly related to variability in brain activation. Individuals post‐stroke with relatively poorer AS task performance showed greater magnitude of activation in left PMd and dorsolateral prefrontal cortex (DLPFC), increased left primary motor cortex‐PMd connectivity, and decreased left PMd‐DLPFC connectivity. Changes in the premotor‐prefrontal component of the motor network during complex movement conditions may negatively impact the performance and learning of skilled movement and may be a prime target for rehabilitation protocols aimed at improving the function of residual brain circuits after stroke. Hum Brain Mapp 37:1816–1830, 2016. © 2016 Wiley Periodicals, Inc .     

Cyclic time course of motor excitability modulation during the observation of a cyclic hand movement

The observation of a sinusoidal flexion-extension of the wrist was utilized to determine the continuous time course and phase relation between observed movement and its effects on the observer's motor pathways. While observing movements performed by others, the observers' cortical motor areas and spinal circuits were activated, reflecting the specific temporal and muscular pattern of the actual movement (motor resonance). H-reflexes and motor-evoked potentials (MEPs) were elicited, respectively, by electrical stimulation of the median nerve and magnetic stimulation of the appropriate cortical area, in the right forearm muscle Flexor Carpi Radialis (FCR) of subjects who were observing a 1-Hz cyclic oscillation of the right prone hand executed by a different person. Observation elicited a parallel cyclic excitability modulation of the observer's H-reflex and MEP responses with identical period as the observed movement. Modulation was phase advanced, as is muscle activation with respect to the real movement. The same results were obtained when the observed hand oscillation was executed with different frequency (1.6 Hz) and when the hands of mover and observer were supine. No motor resonance was elicited by observing the oscillation of a metal platform. The excitability modulation of MEPs simultaneously monitored in both antagonists of the observer's forearm (FCR and Extensor Carpi Radialis, ECR) was in almost perfect phase opposition, reflecting their natural reciprocal activation during the execution of a hand oscillation. These findings suggest that during observation, motor pathways are modulated subliminally reproducing with high temporal fidelity the motor commands needed to execute the observed movement.     

Slowly progressive apraxia: a MRI and positron tomography in 4 cases

Four right-handed patients (69, 58 and 68 year-old men; 85 year-old woman) complained of motor difficulties with their left hand (3 cases), or both hands predominant on the left side (1 case). Continuous (1 case) or intermittent (2 cases) myoclonus was noted in the left arm. These disorders gradually progressed for 3 to 10 years. Clinical examination disclosed absence of motor, sensory (except in 1 case), or visual deficit. There were no cerebellar signs, no parkinsonian features (except for mild rigidity in 1 case), and no oculomotor abnormality. On the other hand, neuropsychological examination showed evidence of visuo-constructive apraxia in all cases, dressing apraxia in 3/4 cases and writing impairment in 3/4 cases. There was no amnesia, no aphasia and no intellectual impairment. MRI showed atrophy of the parietal areas, predominant on the right side. A positron emission tomography study was performed in all cases, and twice in 1 case. Cortical energy metabolism was measured using either 18 F-fluorodeoxyglucose or 15 O-Oxygen, to calculate the cerebral metabolic rate of glucose (CMRglu) or oxygen (CMRO2) respectively. Cortical metabolism was significantly decreased in the whole cortex of the right hemisphere in 3 cases, and was also reduced in the cortex of the left hemisphere, significantly in 1/3 studied planes. Moreover, regional metabolic indices (CMRO2 or CMRglu/cortex) showed a significant decrease in both the right and left posterior associative areas (temporo-parieto-occipital cortex), predominantly marked on the right side in 3 cases, indicating bilateral cortical dysfunction. At follow-up, one patient became progressively demented, another had visuo-spatial disorders indicating a lesion of both parietal areas. The relationships of our cases with the slowly progressive apraxia syndrome and with corticobasal degeneration are discussed.