Differences of cortical activation pattern between cortical and corona radiata infarct.

The aim of this study was to elucidate the differences of cortical activation pattern between patients with cortex (CO) infarct and those with corona radiata (CR) infarct. Twenty chronic patients with cerebral infarct and 11 normal subjects were recruited. The patients were classified into two groups according to infarct location: CO and CR group. After functional MRI was performed during the motor task of hand grasp-release movements, the hand motor function was assessed. The CO group tended to be activated on the contralateral primary sensori-motor cortex, whereas the CR group largely showed activation of the bilateral primary sensori-motor cortex. Namely, there was significantly more lateralized activation pattern of primary sensori-motor cortex in the CO group than in the CR group. Additionally, the CO group had better hand motor function than the CR group. Our results suggest that the motor recovery mechanism vary according to the lesion location between CO and CR infarct, indicating that the adaptive cortical reorganization proceeds under different patterns according to the lesion location.

Degeneration speed of corticospinal tract in patients with cerebral infarct.

OBJECTIVES: Diffusion tensor image tractography (DTT) could be useful for exploring the state of the corticospinal tract (CST) at the level of the subcortical white matter. The purpose of this study was to demonstrate the speed of degeneration of the CST in patients with cerebral infarct, using DTT. DESIGN: Two patients with middle cerebral artery territory infarct were recruited for this study. DTT was performed 5 times with an interval of 7 days, starting at 2 days after onset, using a 1.5-T system with a synergy-L Sensitivity Encoding head coil. The termination criteria used were fractional anisotrophy < 0.3, 0.2, 0.1, respectively, and an angle change > 45 degrees . RESULTS: Detection of CST degeneration began at the 9 day DTT in both patients. The most rapid CST degeneration was noted for 7 days at 16 days from onset. We did not detect any tract in the affected hemisphere of both patients at the 23-day DTT. CONCLUSIONS: We demonstrated that CST degeneration begins before 9 days from onset and progresses rapidly in patients with middle cerebral artery territory infarct. It seems that the CST degeneration began earlier than expected.

Cortical activation changes induced by visual biofeedback tracking training in chronic stroke patients.

OBJECTIVES: We tried to examine whether visual biofeedback tracking training (VBTT) can improve both the gait performance and cortical activation pattern in chronic stroke patients. DESIGN: We enrolled 10 chronic hemiparetic patients with stroke(mean age 46.3 +/- 5.19 years). The patients were randomly assigned to the training group (5 patients) or the control group (5 patients). VBTT was to follow the PC-generated sine waves with the knee joint electrogoniometer, and the two sine waves should appear as close to overlapping as possible on the PC monitor. The training was performed for 39 minutes/day, 5 days/week, for 4 weeks. Pre-training and post-training accuracy of tracking, functional status of gait, and functional MRI (fMRI) were measured. fMRI was performed at 1.5 T in parallel with timed knee flexion-extension movements at a fixed rate. RESULTS: The accuracy of the tracking performance, walking speed, and motor scale for gait improved in the training group. Primary sensorimotor cortex (SM1) cortical activation shifted significantly from the unaffected to the affected hemisphere in the training group. CONCLUSIONS: We demonstrated that cortical activation changes occurred with gait function improvement in chronic stroke patients throughout the 4-week VBTT program. It seems that the cortical reorganization was induced by VBTT.

Motor recovery via the peri-infarct area in patients with corona radiata infarct.

OBJECTIVES: Diffusion tensor image tracography (DTT) could be useful for exploration of the state of the corticospinal tract at the subcortical white matter level. We investigated the neural pathway associated with motor recovery in the patients with corona radiata infarct (CR) using DTT. DESIGN: Three hemiparetic patients who showed severe weakness of the affected upper extremity at stroke onset, were recruited. DTT was performed twice (subacute and chronic stage) using 1.5-T system. Three-dimensional reconstructions of the fiber tracts were obtained with FA <0.2, angle >45 degrees as termination criteria. RESULTS: In all patients, the motor function of the affected upper extremity has recovered to be functional state at second DTT scanning. The motor tracts of the affected hemisphere were observed to pass along the posterior portion of the CR infarct on both the first and second DTT. CONCLUSIONS: It seems that the motor function of the affected upper extremity of the patients recovered via the posterior portion of infarct. This finding may reflect functional reorganization of the motor pathway following damage to the corticospinal tract.

Peri-infarct reorganization of motor function in patients with pontine infarct.

OBJECTIVES: Combined functional MRI (fMRI) and diffusion tensor tractography (DTT) imaging provides a powerful vehicle for the investigation of motor recovery mechanisms. Using this combined method, we investigated the motor recovery mechanism in patients with pontine infarct. DESIGN: We evaluated six healthy control subjects and two patients with pontine infarct at 6 months from onset. fMRI was performed at 1.5 T with timed hand grasp-release movements. For DTT, we used each of the 32 noncollinear diffusion-sensitizing gradients. Three-dimensional reconstructions of the fiber tracts were obtained with FA <0.3, angle >45 degrees as termination criteria. RESULTS: fMRI data revealed activation only in the contralateral primary sensorimotor cortex during movement of either hand. DTI findings from controls and the unaffected hemisphere of the patients showed that the corticospinal tract descended through the known corticospinal tract pathway. However, the tracts of the affected hemisphere in the patients were observed to pass along peri-infarct areas (patient 1: lateral, patient 2: posterior) in the pons. CONCLUSIONS: It seems that the peri-infarct areas compensate for corticospinal tract damage at the pons; this may be one mechanism of motor recovery for patients with pontine infarct.

Motor recovery mechanism of diffuse axonal injury: a combined study of transcranial magnetic stimulation and functional MRI.

PURPOSE: The purpose of this study was to investigate the motor recovery mechanism following diffuse axonal injury (DAI) using transcranial magnetic stimulation (TMS) and functional MRI (fMRI). METHODS: Twenty-six hands of 13 control subjects and 14 affected hands of 8 patients (two hemiparetics and six quadriparetics) were evaluated. All the patients were initially diagnosed with DAI and were evaluated after they had reached their maximal motor recovery. fMRI was performed at 1.5 T using a hand grasp-release movement paradigm and TMS was applied with a round coil over the vertex. RESULTS: fMRI revealed that both normal subjects and patients with DAI showed increased contralateral primary sensori-motor cortex activation during affected hand movement. The motor evoked potentials (MEPs) of the patient group was slightly delayed in latency and significantly increased in duration and turns. The relative MEP amplitude, phase, and excitatory threshold were not significantly different between the groups. CONCLUSIONS: These findings may indicate the heterogeneity of the axons in the recovery process of the corticospinal tract. It seems that the motor recovery in patients who had suffered DAI was attributable to the recovery of the corticospinal tract.

Changes in plasma concentrations of risperidone and 9-hydroxyrisperidone and the associated clinical effects during the switch from oral risperidone to extended-release paliperidone tablets in patients with schizophrenia.

This study aimed to investigate changes in plasma concentrations of risperidone and 9-hydroxy-risperidone (9-OHR) and the associated clinical effects when switching from oral risperidone to extended-release (ER) paliperidone in patients with schizophrenia. This study included 25 patients with schizophrenia. Following a one-week screening period with a stable dose of risperidone, a six-week open-label switch study from risperidone to extended-release paliperidone (paliperidone ER) was conducted. Efficacy and safety assessments were performed on Day 1 and at Weeks 1, 2, 4, and 6. Plasma levels of the active fractions of oral risperidone and paliperidone ER were measured on Day 1 and at Week 1, respectively. Plasma levels of the active moiety (risperidone plus 9-OHR) while taking risperidone (mean dose: 4.0 mg) were significantly higher than plasma levels of 9-OHR while taking 6 mg of paliperidone ER. For 12 subjects taking only 3 mg of risperidone, plasma concentrations of the active moiety of risperidone were also significantly higher than those of 9-OHR while taking 6 mg of paliperidone ER. The amount of reduction in plasma levels was correlated with a temporal deterioration of clinical symptoms. These findings suggest that for patients with schizophrenia taking 3 mg or more of risperidone, an initial switching dose of 6 mg of paliperidone ER may be relatively low in terms of subsequent plasma concentrations and the associated clinical response.

Preservation of the integrity of the corticospinal tract in a patient with medulla infarct.

Diffusion tensor tractography allows the visualization of the corticospinal tract (CST). In the current study, we attempted to demonstrate the preservation of the integrity of the CST within an infarct in a hemiparetic patient with a medulla infarct. A 76-yr-old male patient showed severe paralysis of the left extremities at stroke onset. Over the 4 mos following onset, motor functions of the affected extremities rapidly recovered to a normal state. On the diffusion tensor tractography taken at 1 wk after onset, the tract of the both hemispheres descended through the known CST pathway. Notably, the tract of the affected (right) hemisphere descended through the anterior portion of the infarct in the medulla. The motor-evoked potential obtained from the affected (left) hand muscle had the characteristics of the CST. In conclusion, we demonstrated that the integrity of CST had been spared in the anterior portion of the medulla infarct by using diffusion tensor tractography and transcranial magnetic stimulation.

Demonstration of recovery of a severely damaged corticospinal tract: a diffusion tensor tractography and transcranial magnetic stimulation follow-up study.

We demonstrated the recovery of a severely damaged corticospinal tract (CST) in a 45-year-old female patient with intracerebral hemorrhage using diffusion tensor tractography and transcranial magnetic stimulation. Two longitudinal evaluations were conducted. There was no evidence of a CST in the affected hemisphere on the first evaluation. However, we observed evidence of a CST on the second evaluation. It seems that the affected motor function was recovered through the recovery of the damaged CST.

Cortical reorganization of hand motor function to primary sensory cortex in hemiparetic patients with a primary motor cortex infarct.

OBJECTIVE: To show cortical reorganization in hemiparetic patients with a primary motor cortex (M1) infarct including the precentral knob by using functional magnetic resonance imaging (fMRI). DESIGN: Case-control. SETTING: Outpatient clinics in the rehabilitation department of a university hospital. PARTICIPANTS: Two stroke patients and 20 control subjects. INTERVENTIONS: By using fMRI, we evaluated the hand motor function of 2 hemiparetic stroke patients, who had made some recovery from complete paralysis of the affected hand, and 20 control subjects. MAIN OUTCOME MEASURES: fMRI was performed by using the blood oxygen level-dependent technique at 1.5 T with a standard head coil. The motor task paradigm consisted of hand grasp-release movements. RESULTS: The contralateral primary sensorimotor cortex was activated by the hand movements of the control subjects and of the unaffected side of the 2 patients. Only the contralateral (infarct side) primary sensory cortex (S1) was activated by the movements of the affected hand of the 2 patients, a result that was not observed in the control subjects or with the unaffected hand in the stroke patients. CONCLUSIONS: The hand motor function associated with the infarcted M1 in our patients was reorganized into the S1. These results suggest cortical reorganization in patients with an M1 infarct.