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Diffusion MRI improves detection of abnormalities in white matter tracts in cerebral palsy (CP). Relationships between diffusion measurements and hand function are largely unexplored. We aimed first to assess microstructure of corticofugal fibers, and second to explore associations between tract injury as assessed by quantitative analysis of diffusion MRI and hand function in children with unilateral CP. Methods: In this cross-sectional study, 15 children with unilateral CP (6 boys, median age 12.4 years, min 7.2, max 17) and 24 controls were included (9 boys, median age 12.7 years, min 8.8, max 17.3). Hand function was assessed with the Box and Blocks (B&B) test. Magnetic resonance diffusion data ( b value = 1,000 s/mm 2 , 45 directions) were collected on a 1.5-T scanner. Fractional anisotropy (FA), mean diffusivity (MD), and tensor eigenvalues were measured bilaterally in the cerebral peduncle (ROI1), the posterior limb of the internal capsule (PLIC, ROI2), and corticofugal fibers connecting these regions. Results: In children with CP, FA in both ROIs and the partial tract corresponding to the affected hand was significantly lower compared to controls. This was caused by an increase in diffusivity perpendicular to the tract. After controlling for age, mean FA contralateral to the affected hand correlated with B&B scores, which was independent of lesion type or number of voxels in the partial tract, cerebral peduncle, or PLIC. Conclusions: FA in corticofugal fibers is a sensitive marker of damage to the motor system and correlates with hand function in CP. Using FA may improve early prediction of outcome. Neurology ® 2011;77:775–783

To investigate the potential relationship between insulin resistance (IR) and white matter (WM) microstructure using diffusion tensor imaging in cognitively healthy middle-aged and older adults.Diffusion tensor imaging was acquired from 127 individuals (age range 41-86 years). IR was evaluated by the homeostasis model assessment of IR (HOMA-IR). Participants were divided into 2 groups based on HOMA-IR values: "high HOMA-IR" (≥2.5, n = 27) and "low HOMA-IR" (2.5, n = 100). Cross-sectional voxel-based comparisons were performed using Tract-Based Spatial Statistics and anatomically defined regions of interest analysis.The high HOMA-IR group demonstrated decreased axial diffusivity broadly throughout the cerebral WM in areas such as the corpus callosum, corona radiata, cerebral peduncle, posterior thalamic radiation, and right superior longitudinal fasciculus, and WM underlying the frontal, parietal, and temporal lobes, as well as decreased fractional anisotropy in the body and genu of corpus callosum and parts of the superior and anterior corona radiata, compared with the low HOMA-IR group, independent of age, WM signal abnormality volume, and antihypertensive medication status. These regions additionally demonstrated linear associations between diffusion measures and HOMA-IR across all subjects, with higher HOMA-IR values being correlated with lower axial diffusivity.In generally healthy adults, greater IR is associated with alterations in WM tissue integrity. These cross-sectional findings suggest that IR contributes to WM microstructural alterations in middle-aged and older adults.

Background and purpose: Although dysarthria is a frequent symptom in cerebral ischemia, there is little information on its anatomic specificity, spectrum of associated clinical characteristics, and etiologic mechanisms. Methods: An investigation of 68 consecutive patients with sudden onset of dysarthria due to a single infarction confirmed by MRI or CT was conducted. Results: Dysarthria was associated with a classic lacunar stroke syndrome in 52.9% of patients. Isolated dysarthria and dysarthria–central facial and lingual paresis occurred in 2.9% (n = 2) and 10.3% (n = 7), respectively. Dysarthria–clumsy hand syndrome was observed in 11.7% (n = 8) of patients and associated with pure motor hemiparesis and/or ataxic hemiparesis in 27.9% (n = 19). The lesions were due to small-vessel disease in 52.9% (n = 36), to cardioembolism in 11.8% (n = 8), and to large-vessel disease in only 4.4% (n = 3) of cases. Infarctions were located in the lower part of the primary motor cortex (5.9%; n = 4), middle part of the centrum semiovale (23.5%; n = 16), genu and ventral part of the dorsal segment of the internal capsule (8.8%; n = 6), cerebral peduncle (1.5%; n = 1), base of the pons (30.9%; n = 21), and ventral pontomedullary junction (1.5%; n = 1). Isolated cerebellar infarctions affected the rostral paravermal region in the superior cerebellar artery territory. Conclusions: Extracerebellar infarcts causing dysarthria were located in all patients along the course of the pyramidal tract. This finding correlates with the frequent occurrence of associated pyramidal tract signs in 90.7% (n = 62) of patients. Isolated cerebellar infarcts leading to dysarthria were in all cases located in the territory of the superior cerebellar artery.

Article abstract— A 33-year-old man developed a complete third nerve palsy in the setting of acute bacterial endocarditis. MRI revealed an ischemic stroke in the cerebral peduncle involving the third nerve fascicle. Subsequently, he was observed to have paradoxic elevation of the eyelid on adduction and downgaze. To the authors’ knowledge, this is the first demonstration of oculomotor synkinesis after an acquired, ischemic CNS lesion.

A 71-year-old man had acute onset of ataxia, dysarthria, and visual blurring, which progressed in a stuttering fashion to a locked-in syndrome. Only pupillary reflexes and extraocular movements (both vertical and lateral) were ultimately preserved. MRI showed bilateral infarctions of the cerebral …

A 32-year-old woman with acute lymphocytic leukemia had abrupt onset of headache, decreased sensorium, and dilated left pupil. Lumbar punctures with intrathecal methotrexate had been done 4 and 7 days before her collapse. When she awakened from emergency evacuation of a subdural hematoma, there was ipsilateral hemiplegia and MRI showed a cerebral peduncle lesion (figure). Now, 32 months later, hemiparesis …

Ten patients became locked-in after head and neck trauma. Five had a prompt onset due to either direct trauma or secondary infarction of the brainstem. A delay of 6 to 48 hours in four other patients was probably the interval between vertebral artery damage and vertebrobasilar arterial occlusion. The last patient sustained ischemia and compression of the cerebral peduncles from tentorial herniation.

Corneal reflex latencies were studied in 53 patients with cerebral lesions. Five distinct types of abnormality were identified in 30 of these patients. The findings suggest that the lower postcentral region has an excitatory influence upon interneurons of the lateral reticular formation of the lower brainstem mediating the trigeminofacial connections of the corneal reflex. This influence descends by way of postcentral corticobulbar fibers that pass through the cerebral peduncle and pyramidal tract.

Peduncular hallucinations are associated with intrinsic lesions of the midbrain. We report transient peduncular hallucinations due to extrinsic compression of the midbrain by a cystic craniopharyngioma. The peduncular hallucinations resolved promptly after drainage of the cyst.

Three patients with medial ventral cerebellar peduncular hemorrhages presented with a characteristic syndrome. This included (1) ipsilateral ataxia, (2) lower motor neuron type facial weakness, and (3) ipsilateral gaze paresis. The gaze paresis could not be overcome with a doll's head maneuver. The findings are explained by compression of the facial colliculus, with involvement of the sixth nerve nucleus and the middle cerebellar peduncle. Two patients were hypertensive; one was normotensive, and no etiology was identified with angiography. Of 40 patients with cerebellar hemorrhage seen at our institution, only those with medial cerebellar peduncular hematomas demonstrated this clinical triad, and we have not seen this clinical triad in other pathologic conditions. The diagnosis of a small medial cerebellar peduncular hemorrhage was established by CT. In two patients, repeat CT showed complete hematoma resolution. The patients shared a favorable prognosis.

A 28-year-old man had a chronic locked-in syndrome following tentorial herniation caused by an epidural hematoma. Postmortem examination revealed bilateral corticospinal tract degeneration caudal to the midbrain, with infarction of the right internal capsule just rostral to the cerebral peduncle and pressure necrosis of the pyramidal portion of the left cerebral peduncle.