Motor Organization in Schizencephaly: Outcomes of Transcranial Magnetic Stimulation and Diffusion Tensor Imaging of Motor Tract Projections Correlate with the Different Domains of Hand Function.

OBJECTIVE: Schizencephaly is a rare congenital malformation that causes motor impairment. To determine the treatment strategy, each domain of the motor functions should be appropriately evaluated. We correlated a color map of diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS) with the hand function test (HFT) to identify the type of hand function that each test (DTI and TMS) reflects. Further, we attempted to demonstrate the motor neuron organization in schizencephaly. METHOD: This retrospective study was conducted on 12 patients with schizencephaly. TMS was conducted in the first dorsal interosseous (FDI), biceps (BB), and deltoid muscles of the upper extremity, and contralateral MEP (cMEP) and ipsilateral MEP (iMEP) were recorded. The HFT included the grip strength, box and block (B&B), and 9-hole peg test. The schizencephalic cleft was confirmed using magnetic resonance imaging, and the corticospinal tract (CST) was identified using the color map of DTI. The symmetry indices for the peduncle and CST at pons level were calculated as the ratios of the cross-sectional area of the less-affected side and that of the more-affected side. RESULT: In the more-affected hemisphere TMS, no iMEP was obtained. In the less-affected hemisphere TMS, the iMEP response was detected in 9 patients and cMEP in all patients, which was similar to the pattern observed in unilateral lesion. Paretic hand grip strength was strongly correlated with the presence of iMEP (p = 0.044). The symmetry index of the color map of DTI was significantly correlated with the B&B (p = 0.008, R 2 = 0.416), whereas the symmetry index of the peduncle was not correlated with all HFTs. CONCLUSION: In patients with schizencephaly, the iMEP response rate is correlated with the hand function related to strength, while the symmetricity of the CST by the color map of DTI is correlated with the hand function associated with dexterity. Additionally, we suggest the possible motor organization pattern of schizencephaly following interhemispheric competition.

Relationship between ataxia and inferior cerebellar peduncle injury in patients with cerebral infarct.

INTRODUCTION: The inferior cerebellar peduncle (ICP) is a major neural tract in the cerebellum and is involved in coordination of movement and proprioceptive; therefore, ICP injury can be accompanied by poor coordination of movement, including ataxia. In this study, using diffusion tensor tractography (DTT), we investigated the relationship between ataxia and ICP injury in patients with cerebral infarct. METHODS: We recruited 14 stroke patients with ataxia after the onset of stroke and 12 normal subjects. The Score of Assessment and Rating of Ataxia (SARA) was used to evaluate ataxia. The values of fractional anisotropy (FA), apparent diffusion coefficient, and fiber number (FN) of the ICP were measured for the diffusion tensor imaging parameters. RESULTS: Significant differences were observed in the FA and FN values of the ICP in the affected hemisphere between the patient and control groups (P < .05). In addition, the FN value of the ICP in the affected hemisphere showed a negative correlation with SARA (r = -0.538, P < .05). However, parameters of the ICP in the unaffected hemisphere or the FN value in the unaffected hemisphere showed no correlation with SARA (P > .05). CONCLUSION: We found that the ataxia severity was closely related to the severity of ICP injury in patients with cerebral infarct. Our results suggest that evaluation of the ICP using DTT would be useful for patients with ataxia after cerebral infarct.

Rare presentation of an isolated bilateral cerebral peduncular infarction: A case report and review of the literature.

RATIONALE: Due to the rarity of bilateral cerebral peduncular infarction (BCPI), its symptoms and prognosis are not clear. It is necessary to collect cases of pure cerebral peduncular infarction, explore the etiology and anatomy of midbrain infarction in depth, and develop meaningful tools for explaining clinical symptoms and predicting prognosis of patients. PATIENT CONCERNS: We here provide a case of isolated BCPI with uncommon symptoms of ataxia, dysarthria, sensory disturbance, normal muscular strength, and full eye movements. DIAGNOSES: Diffusion weighted images and apparent diffusion coefficient map of our patient revealed acute and isolated bilateral peduncle cerebrum infarction. INTERVENTIONS: Drugs that could improve circulation and antiplatelet were used in therapy. OUTCOMES: The infarct size was enlarged and new infarction was identified in the splenium of the corpus callosum and pons. The patient developed progressed disorder of consciousness and died at the eleventh day. LESSONS: We inferred that the symptoms of ataxia, dysarthria, sensory disturbance, and mild paresis of the extremities could be prominent features of patients with pure cerebral peduncular infarction. We hypothesize that pure BCPI is also related to severe basilar artery stenosis or occlusion and there is no collateral circulation from PCA. This may explain the corresponding distribution of cerebral peduncular infarction and its poor prognosis. For these reasons, exploring etiology and anatomy of midbrain infarction in depth would have clinical value for predicting symptoms and prognosis.

Jacques Jean Lhermitte and the syndrome of peduncular hallucinosis.

Jacques Jean Lhermitte (1877-1959) was among the most accomplished neurologists of the 20th century. In addition to working as a clinician and instructor, he authored more than 800 papers and 16 books on neurology, neuropathology, psychiatry, and mystical phenomena. In addition to the well-known "Lhermitte's sign," an electrical shock-like sensation caused by spinal cord irritation in demyelinating disease, Lhermitte was a pioneer in the study of the relationship between the physical substance of the brain and the experience of the mind. A fascinating example of this is the syndrome of peduncular hallucinosis, characterized by vivid visual hallucinations occurring in fully lucid patients. This syndrome, which was initially described as the result of a midbrain insult, also may occur with injury to the thalamus or pons. It has been reported as a presenting symptom of various tumors and as a complication of neurosurgical procedures. Here, the authors review the life of Lhermitte and provide a historical review of the syndrome of peduncular hallucinosis.

Severe seizures as a side effect of deep brain stimulation in the dorsal peduncular cortex in a rat model of depression.

Deep brain stimulation (DBS) has shown to have antidepressant effects in both human trials and animal studies. However, the optimal target and the underlying therapeutic mechanisms remain to be determined. In this study, we investigated if high frequency (HF) DBS in the dorsal peduncular cortex (DPC) alleviates depressive-like behavior in an experimental model of depression. Surprisingly, HF DBS in the DPC caused acute induction of seizures in ~40% of animals stimulated with clinically relevant stimulation parameters. Reducing the stimulation's amplitude by 50% did not alter seizure occurrence. Electroencephalographic (EEG) recordings showed seizures up to Racine stage IV lasting up to 4 min after cessation of stimulation. We conclude that HF DBS in the DPC is not suitable for mood-related experiments in rats but could be a potential model for seizure induction.

Asymmetry of Cerebral Peduncles for Predicting Motor Function Restoration in Young Patients Before Hemispherectomy.

OBJECTIVE: Hemispherectomy has been used successfully for patients with medically intractable epilepsy. However, it is difficult to predict postoperative motor function. The aim of the present study was to analyze whether the preoperative asymmetry of cerebral peduncles could be used to predict motor function restoration before hemispherectomy for young patients with medically intractable epilepsy. METHODS: The clinical record and magnetic resonance imaging data of 53 patients were analyzed retrospectively. The correlation between preoperative cerebral peduncle asymmetry ratio (pCPAR) and pre- and postoperative changes in motor function was evaluated, as well as the influencing factors for pCPAR, such as duration and etiology factors. The restoration of motor function was defined as changes in pre- and postoperative hemiparesis. RESULTS: The pCPARs of patients with improved and unchanged hemiparesis were significantly greater than that of worsened patients. Patients with a pCPAR of more than 1.5 had an obvious restorative capacity of motor function of the intact hemisphere, and these patients had a lower risk of worsening hemiparesis. The duration in the improved/unchanged and worsened groups was 5.84 ± 3.85 years and 2.67 ± 2.03 years, respectively. Furthermore, there were more patients with no-progressive pathology in the group in whom pCPAR was more than 1.5. CONCLUSIONS: pCPAR is a useful and objective indicator for predicting the restoration of motor function in pediatric patients with medically intractable epilepsy before hemispherectomy. Most patients with nonprogressive pathology and a duration of more than 5 years presented with greater pCPARs, exhibited better restoration of motor function, and had less risk of worsening hemiparesis.

Utility of Fractional Anisotropy in Cerebral Peduncle for Stroke Outcome Prediction: Comparison of Hemorrhagic and Ischemic Strokes.

BACKGROUND: Diffusion-tensor fractional anisotropy (FA) has been used for predicting stroke outcome. However, most previous studies focused on patients with either hemorrhagic or ischemic stroke. The aim of this study was to assess the correlation between FA and outcome for patients with hemorrhagic stroke and those with ischemic stroke, and then compare their correlation patterns. METHODS: This study sampled 40 hemorrhagic and 40 ischemic stroke patients from our previously published reports. Diffusion-tensor images were obtained on days 14-21, and FA images were generated, after which the ratio of FA within the cerebral peduncles of the affected and unaffected hemispheres (rFA) was calculated. Outcome was assessed using Brunnstrom stage (BRS), motor component of the functional independence measure (FIM-motor), and total length of hospital stay (LOS) at discharge from our affiliated rehabilitation hospital. The data were then compared between the hemorrhage and the infarct groups. Correlation analyses between rFA and outcome assessments were performed separately for both groups and then were compared between the groups. RESULTS: The hemorrhage group exhibited significantly more severe BRS, longer LOS, and lower rFA than the infarct group. The correlations between rFA and outcome measures were all statistically significant for both the hemorrhage and the infarct groups. The correlation patterns for BRS and LOS were very similar between the hemorrhage and the infarct groups. However, such similarity was not evident for FIM-motor. CONCLUSIONS: FA in the cerebral peduncles may be used to predict extremity functions and LOS for both types of stroke.

White matter integrity of the cerebellar peduncles as a mediator of effects of prenatal alcohol exposure on eyeblink conditioning.

Fetal alcohol spectrum disorders (FASD) are characterized by a range of neurodevelopmental deficits that result from prenatal exposure to alcohol. These can include cognitive, behavioural, and neurological impairment, as well as structural and functional brain damage. Eyeblink conditioning (EBC) is among the most sensitive endpoints affected in FASD. The cerebellar peduncles, large bundles of myelinated nerve fibers that connect the cerebellum to the brainstem, constitute the principal white matter element of the EBC circuit. Diffusion tensor imaging (DTI) is used to assess white matter integrity in fibre pathways linking brain regions. DTI scans of 54 children with FASD and 23 healthy controls, mean age 10.1 ± 1.0 years, from the Cape Town Longitudinal Cohort were processed using voxelwise group comparisons. Prenatal alcohol exposure was related to lower fractional anisotropy (FA) bilaterally in the superior cerebellar peduncles and higher mean diffusivity (MD) in the left middle peduncle, effects that remained significant after controlling for potential confounding variables. Lower FA and higher MD in these regions were associated with poorer EBC performance. Moreover, effects of alcohol exposure on EBC decreased significantly after inclusion of these DTI measures in regression models, suggesting that these white matter deficits partially mediate the relation of prenatal alcohol exposure to EBC. The associations of greater alcohol consumption with these DTI measures are largely attributable to greater radial diffusivity, possibly indicating poorer myelination. Thus, these data suggest that fetal alcohol-related deficits in EBC are attributable, in part, to poorer myelination in key regions of the cerebellar peduncles.