Internal Capsule Lesions Research Articles

Effects of Magnesium Treatment in a Model of Internal Capsule Lesion in Spontaneously Hypertensive Rats

The study aim was to assess the effects of magnesium sulfate (MgSO(4)) administration on white matter damage in vivo in spontaneously hypertensive rats. The left internal capsule was lesioned by a local injection of endothelin-1 (ET-1; 200 pmol) in adult spontaneously hypertensive rats. MgSO(4) was administered (300 mg/kg SC) 30 minutes before injection of ET-1, plus 200 mg/kg every hour thereafter for 4 hours. Infarct size was measured by T2-weighted magnetic resonance imaging (day 2) and histology (day 11), and functional recovery was assessed on days 3 and 10 by the cylinder and walking-ladder tests. ET-1 application induced a small, localized lesion within the internal capsule. Despite reducing blood pressure, MgSO(4) did not significantly influence infarct volume (by magnetic resonance imaging: median, 2.1 mm(3); interquartile range, 1.3 to 3.8, vs 1.6 mm(3) and 1.2 to 2.1, for the vehicle-treated group; by histology: 0.3 mm(3) and 0.2 to 0.9 vs 0.3 mm(3) and 0.2 to 0.5, respectively). Significant forelimb and hindlimb motor deficits were evident in the vehicle-treated group as late as day 10. These impairments were significantly ameliorated by MgSO(4) in both cylinder (left forelimb use, P<0.01 and both-forelimb use, P<0.03 vs vehicle) and walking-ladder (right hindlimb score, P<0.02 vs vehicle) tests. ET-1-induced internal capsule ischemia in spontaneously hypertensive rats represents a good model of lacunar infarct with small lesion size, minimal adverse effects, and a measurable motor deficit. Despite inducing mild hypotension, MgSO(4) did not significantly influence infarct size but reduced motor deficits, supporting its potential utility for the treatment of lacunar infarct.

Impact of internal capsule lesions on outcome of motor hand function at one year post-stroke

To investigate the association between damage to different levels of the corticofugal tract and long-term hand motor recovery. Prospective cohort study. Seventy-five first-ever middle cerebral artery stroke survivors. Hand motor function was assessed with the Fugl-Meyer Motor Assessment Scale at one year post-stroke. Localization of the corticofugal tract was assessed on axial magnetic resonance imaging slices using a corticofugal mask defining involvement of the motor cortex, corona radiata or internal capsule and combinations of these structures, adjusted for lesion volume. Longitudinal involvement of all 3 levels of the corticofugal tract and partial involvement of the internal capsule were associated with a significant probability of poor motor hand function recovery. The probability of regaining hand function ranged from 54% if the corticofugal tract was only partly affected to 13% if both motor cortex and internal capsule were affected. At one year post-stroke, lesions of the internal capsule were associated with a significantly lower probability of return of isolated hand motor function than lesions of the cortex, subcortex and corona radiata. Since recovery of isolated hand and finger movements is important for regaining a functional upper limb in everyday living, these patients should be identified early post-stroke in order to evaluate specific hand function training.

Experimental Model of Lacunar Infarction in the Gyrencephalic Brain of the Miniature Pig

Lacunar infarction accounts for 25% of ischemic strokes, but the pathological characteristics have not been investigated systematically. A new experimental model of lacunar infarction in the miniature pig was developed to investigate the pathophysiological changes in the corticospinal tract from the acute to chronic phases. Thirty-five miniature pigs underwent transcranial surgery for permanent anterior choroidal artery occlusion. Animals recovered for 24 hours (n=7), 2 (n=5), 3 (n=2), 4 (n=2), 6 (n=1), 7 (n=7), 8 (n=2), and 9 days (n=1), 2 weeks (n=2), 4 weeks (n=3), and more than 4 weeks (n=3). Neurology, electrophysiology, histology, and MRI were performed. Seven additional miniature pigs underwent transient anterior choroidal artery occlusion to study muscle motor-evoked potentials and evaluate corticospinal tract function during transient anterior choroidal artery occlusion. The protocol had a 91.4% success rate in induction of internal capsule infarction 286+/-153 mm(3) (mean+/-SD). Motor-evoked potentials revealed the presence of penumbral tissue in the internal capsule after 6 to 15 minutes anterior choroidal artery occlusion. Total neurological deficit scores of 15.0 (95% CI, 13.5 to 16.4) and 3.4 (0.3 to 6.4) were recorded for permanent anterior choroidal artery occlusion and sham groups, respectively (P<0.001, maximum score 25) with motor deficit scores of 3.4 (95% CI, 2.9 to 4.0) and 0.0 (CI, 0.0 to 0.0), respectively (P<0.001, maximum score 9). Histology revealed that the internal capsule lesion expands gradually from acute to chronic phases. This new model of lacunar infarction induces a reproducible infarct in subcortical white matter with a measurable functional deficit and evidence of penumbral tissue acutely.

Motor Strokes

The purpose of this research was to investigate the impact of lesion location on motor excitability and motor performance. We studied patients with pure motor strokes in 4 different brain areas: motor cortex lesions (n=7), striatocapsular lesions (n=13), lacunar lesions of the internal capsule (n=13), and paramedian pontine lesions (n=10). Motor performance tests included the 9-hole-peg test and grip strength recordings. Motor excitability was determined by transcranial magnetic stimulation. Motor thresholds, stimulus-response curves, silent periods, motor cortical inhibition, and facilitation were investigated. The 4 groups were clinically similar but showed major differences in motor excitability. Only motor cortex lesions had a loss of intracortical inhibition in the affected hemisphere. In the internal capsule lesion group and the pontine lesion group, stimulus-response curves were depressed on the affected side. All of the subcortical lesions showed a prolongation of the silent period in the paretic side. Motor thresholds were predominantly elevated in the lesioned hemisphere of patients with internal capsule or pontine lesions. Motor performance was correlated with silent period duration in internal capsule lesions and with motor thresholds in internal capsule and pontine lesions. Motor cortex lesions exhibited deficient inhibitory properties. In contrast, subcortical lesions displayed an enhancement of inhibition. Internal capsule and pontine lesions affecting the corticospinal tract on different levels particularly impaired neuronal recruitment. Our results suggest that the lesion location determines a specific pattern of motor excitability changes.

Early movement impairments in a patient recovering from optic ataxia

Since Balint’s first description, optic ataxia has been considered as a pure visuomotor impairment produced by a lesion of the posterior parietal cortex. Beyond general agreement on the parietal involvement in visually guided behaviour, the exact role of the dorsal posterior parietal cortex in the temporal aspects of visuomotor control remains unclear. Recent evidence has indicated a specific involvement of the parietal cortex in the on-line visual guidance of movement. Here, we report the motor performance of, GT, a patient recovering from an optic ataxia due to a right focal lesion of the dorsal posterior parietal cortex. When asked to reach and grasp, with his left contralesional hand, different sized objects, located at different positions from his body, GT showed an apparently complete recovery from optic ataxia. However, the early kinematic aspects of GTs prehension movement were not normally tuned either by intrinsic or extrinsic visual properties of objects. At variance with both an age-matched control group and a neurological patient with a right internal capsule lesion and no sign of optic ataxia, GTs latencies to peak wrist acceleration and peak velocity were not modulated by object location. A similar defective pattern was present in GTs grasping component where, despite the sparing of the classical scaling of grip aperture, object size did not modulate the peak velocity of grip aperture. These results constitute evidence that the posterior region of the dorsal parietal cortex, besides playing a role in the on-line control of movement execution may also be involved in the programming of early kinematics parameters.

Evaluation of acute ischemic stroke using quantitative EEG: A comparison with conventional EEG and CT scan

The sensitivity of quantitative electroencephalogram (EEG) was compared with that of conventional EEG in patients with acute ischaemic stroke. In addition, a correlation between quantitative EEG data and computerized tomography (CT) scan findings was carried out for all the areas of lesion in order to reassess the actual role of EEG in the evaluation of stroke. Sixty-five patients were tested with conventional and quantitative EEG within 24 h from the onset of neurological symptoms, whereas CT scan was performed within 4 days from the onset of stroke. EEG was recorded from 19 electrodes placed upon the scalp according to the International 10-20 System. Spectral analysis was carried out on 30 artefact-free 4-sec epochs. For each channel absolute and relative power were calculated for the delta, theta, alpha and beta frequency bands and such data were successively represented in colour-coded maps. Ten patients with extensive lesions documented by CT scan were excluded. The results indicated that conventional EEG revealed abnormalities in 40 of 55 cases, while EEG mapping showed abnormalities in 46 of 55 cases: it showed focal abnormalities in five cases and nonfocal abnormalities in one of six cases which had appeared to be normal according to visual inspection of EEG. In a further 11 cases, where the conventional EEG revealed abnormalities in one hemisphere, the quantitative EEG and maps allowed to further localize abnormal activity in a more localized way. The sensitivity of both methods was higher for frontocentral, temporal and parieto-occipital cortical-subcortical infarctions than for basal ganglia and internal capsule lesions; however, quantitative EEG was more efficient for all areas of lesion in detecting cases that had appeared normal by visual inspection and was clearly superior in revealing focal abnormalities. When we considered the electrode related to which the maximum power of the delta frequency band is recorded, a fairly close correlation was found between the localization of the maximum delta power and the position of lesions documented by CT scan for all areas of lesion excepting those located in the striatocapsular area.

Acute Cerebrovascular Accident and Lower Urinary Tract Dysfunction: A Prospective Correlation of the Site of Brain Injury with Urodynamic Findings

Purpose We evaluated the effects of an acute cerebrovascular accident on the lower urinary tract and correlated the site of cerebrovascular accident with findings on urodynamic study. Materials and Methods A total of 45 men and 15 women underwent a complete urodynamic study with electromyography within 72 hours of a cerebrovascular accident. Patients were divided into 5 different groups based on urodynamic findings. Results The majority of cortical and internal capsule lesions resulted in detrusor hyperreflexia. A total of 28 patients (47 percent) had urinary retention, mainly due to detrusor areflexia (75 percent). Of 20 patients with hemorrhagic infarcts 17 (85 percent) had areflexia, compared to only 4 of 40 (10 percent) with ischemic infarcts. All 6 patients with cerebellar infarction had detrusor areflexia. Conclusions Our results confirm many previously reported findings. In addition, there was a specific correlation of cerebellar and hemorrhagic infarctions with detrusor areflexia.

Tonic “Seizures” in a patient with brainstem demyelination: MRI study of brain and spinal cord

Tonic seizures are a poorly understood manifestation of demyelinating disease, first reported in 4 patients with multiple sclerosis. We describe a patient with tonic extension of the left limbs caused by a right-sided brainstem lesion as the first manifestation of demyelinating disease. A 19-year-old man was referred with a 4-month history of spontaneous attacks of mild paresthesias of the left arm and leg, followed by 15–45 s of rigid extension of the left limbs, occurring up to 25 times per day. Two months after onset, an MRI scan revealed areas of T 2 abnormality in the lateral right cerebral peduncle and deep frontal white matter. The EEG was normal, including during hyperventilation which induced a typical episode. All attacks were successfully suppressed by carbamazepine, phenytoin, and valproate monotherapy. Serologic testing for toxoplasmosis, cytomegalovirus, Epstein-Barr virus, Lyme disease, and HIV was negative. Cerebrospinal fluid oligoclonal bands were absent but cerebrospinal fluid immunoglobulin G was mildly elevated (4.2 mg/dl). Over the next 30 months, serial MRIs revealed a normal spinal cord and persistence of the midbrain lesion, with resolution of some of the white matter lesions but reappearance of others. At 46 months, the midbrain lesion resolved on MRI, and the spasms no longer occurred spontaneously, nor could they be elicited by hyperventilation. While two previous reports have shown internal capsule lesions to underlie the tonic spasms in demyelinating disease, this is the first report in which a brainstem lesion has been causative.

脳血管障害に伴うｃｒｏｓｓｅｄ ｃｅｒｅｂｅｌｌａｒ ａｔｒｏｐｈｙ

A neuroradiological study of crossed cerebellar atrophy (CCA) was performed using X-ray CT in 103 patients suffering from unilateral supratentorial cerebrovascular diseases. CCA was demonstrated in 9 (8.7%) of 103 patients. No difference between the occurrence of CCA in cerebral hemorrhage and that in cerebral infarction was found. CCA was seen in the chronic stage of cerebrovascular disease more than 3 years since stroke occurrence, and was found to be present more frequently and to a greater extent 7 years later. No correlation between the site of bleeding and the occurrence of CCA was found. Trans-synaptic degeneration of the corticopontocerebellar tract was considered in CCA following putaminal and combined hemorrhage involving an internal capsule lesion. However, in thalamic hemorrhage, retrograde degeneration within the cerebellorubrothalamic tract was presumed. CCA following cerebral infarction was seen in patients with massive lesions in the territory of the middle cerebral artery. Multivariate analysis showed that lesions of the parietal and frontal lobes appeared to greatly contribute to the development of CCA. As the degeneration and atrophy in the thalamus on the side of the lesion appeared early and frequently, it was suggested that retrograde degeneration of the cerebellorubrothalamic tract participated, in addition to anterograde corticopontocerebellar tract degeneration, in CCA following middle cerebral artery infarction. It is likely that CCA is caused by both transsynaptic degeneration of the corticopontocerebellar tract and the cerebellorubrothalamic tract.

Persistent Word Fluency Deficit in Patients with Dominant Hemisphere Striato-Capsular Lesions: Further Evidence for a Subcortical Role in Language?

The language abilities of a group of five patients with chronic dominant hemisphere striato-capsular lesions and/or deep white matter lesions and whose performance was within normal limits according to the criterion of a standard aphasia examination were described. When compared with an age and sex matched control group, the group of subjects with dominant hemisphere striato-capsular lesions had significantly lower aphasia quotients and word fluency scores on the Western Aphasia Battery and produced significantly more content units in a picture description task than the control group. The performance of the group with basal ganglia and internal capsule lesions was not significantly different from the control group in other tests of language function (e.g., Boston Naming Test, Neurosensory Center Comprehensive Examination for Aphasia). The results of the current study were discussed in relation to their implications for theories of the role of the subcortical structures in language or language related func...

Analysis of voiding disorders in patientswith cerebrovascular accidents

Urodynamic evaluation was undertaken in 33 patients (15 males and 18 females, age range 48-90 years) with voiding problems following cerebrovascular accidents. In the majority of these patients (26) cystometry revealed involuntary contractions of the bladder. The critical volume for involuntary bladder contractions was approximately 200 mL. The majority of patients with cerebral cortex and/or internal capsule lesions had uninhibited relaxation of the sphincter during involuntary bladder contractions, while all of the patients with lesions only in the basal ganglia or thalamus had normal sphincter function. The remaining 7 patients had poor bladder contractions. Correlation of bladder dysfunction with the area of brain injury was not conclusive, but was suggestive of directions to be taken in future research.

一側性大脳障害例の頭振り後眼振について

The head-shaking test (HST) and the caloric test were used in the examination of 31 patients with unilateral internal capsule vascular lesions demonstrated by CT scan.Monophasic, biphasic and triphasic types of HSAN were observed in 13 patients (42%). In subtype A (3 patients, 10%) the first phase of nystagmus was to the side contralateral to that of the lesion, and in subtype B (10 patients, 32%) it was to the same side. The DP type of HSAN, which becomes slightly weaker and continues for at least 30 seconds, was observed in 14 patients (45%), 12 subtype A (39%) and 2 patients subtype B (6%). The first phase inhibited type of HSAN was seen in 1 patient subtype B (3%). No HSAN was observed in 3 patients (10%).Slow-phase velocity (SPV) could be determined in 30 patients; in 16 the caloric test caused DP nystagmus to the side of the lesion and in 14 to the contralateral side. There was no relationship between the direction or the SPV of the first nystagmus in the monophasic, biphasic or triphasic type of HSAN and the direction or the value of DP (%) in the caloric nystagmus. There was also no relationship between the direction of the DP type of HSAN and the direction or the value of DP (%) in the caloric nystagmus.Our results suggest that HSAN in patients with unilateral internal capsule lesions is due to a tonic imbalance, caused by the lesion, of the cortico-fugal tonic fibers ipsilaterally to the vestibulo-ocular system with eyes open in darkness.

Subcortical neglect: quantitation, anatomy, and recovery.

Fifteen patients with right hemispheric subcortical infarcts localized by CT or MRI were evaluated with a neglect testing battery. Trimodal extinction was present in one case, visual extinction in three, tactile in three, and auditory in six. Although frequent (10 cases), hemispatial neglect was rarely severe (3 cases). Three cases recovered completely. Large posterior internal capsule lesions were associated with more frequent impairment on a cancellation test. The probable mechanism of hemispatial neglect was attentional in one case and intentional in six. Visual and auditory extinction is explained by striatonigral mechanisms. Although subcortical structures participate in attentional and intentional behavior, cortical structures can substitute for their functions.

P-148 - Learning deficits following internal capsule lesion in rats and possible involvement of monoamines

P-148 - Learning deficits following internal capsule lesion in rats and possible involvement of monoamines

Quantification of lesion-induced dopaminergic supersensitivity using the rotational model in the house

A dual lesion technique was used to determine the degree of supersensitivity resulting from nigrostriatal lesions in C57BL/6J mice. Internal capsule lesions encroaching on globus pallidus resulted in reliable ipsilateral rotation both to apomorphine and amphetamine. Dose-response curves to apomorphine were determined before and 21 days after 6-hydroxydopamine lesion of the contralateral nigrostriatal pathway. A 31.5-fold shift to the left was observed following the nigrostriatal lesion, with no change in slope. The extent and placement of the internal capsule lesion, as well as the magnitude of supersensitization correspond closely to those previously reported in the rat.

Aphagia and adipsia following unilateral and bilaterally asymmetrical lesions in rats

Abstract Unilateral direct current lesions centered in the internal capsule produced as long as 18 days of aphagia relative to dry meal and as long as 33 days of adipsia. These lesions interrupted fibers from the frontal neocortex and fibers from the globus pallidus. In contrast, unilateral lesions in the hypothalamus produced no more than one day of aphagia or adipsia. Unilateral lesions in the midbrain reticular formation produced as long as 3 days of aphagia and 2 days of adipsia. These anatomical correlates were also demonstrated using the conventional bilaterally symmetrical lesions. Bilaterally asymmetrical lesions (an internal capsule lesion combined with a contralateral midbrain reticular formation lesion), produced as long as 117 days of aphagia and adipsia. Double unilateral control lesions were no more effective than single unilateral lesions.

Psychological Aspects of Rehabilitation

The Wechsler-Bellvue Adult Intelligence Scale was performed to thirty-four hemiplegic patients who were diagnosed as cerebrovascular lesion of internal capsule and ten healthy persons as control. Distributions of age, sex and grade of education of both groups were not statistically significant. The results were as follows:1) The scores of hemiplegic group was lower than that of control group, especially the difference was statistically significant in total verbal scale, total performance scale, information, arithmetic, similarities, digit span and picture arrangement.2) Mean score of total verbal scale of right hemiplegics was lower than that of left hemiplegics, but the difference was not statistically significant except that of arithmetic and digit span.3) Comparing the differences between verbal and performance scale score of performance scale was lower than that of verbal scale and the difference was statistically significant in left hemiplegic and control group, but in right hemiplegic group the difference of them was not significant because of reduction of the score of verbal scale.4) No definite relationship was proved between each scores and the presence of conscious disturbance or the time examined.