Bilateral Cerebellar Dysfunction Research Articles

Catch-Up Saccades in Vestibular Hypofunction: A Contribution of the Cerebellum?

Long-term deficits of the vestibulo-ocular reflex (VOR) elicited by head rotation can be partially compensated by catch-up saccades (CuS). These saccades are initially visually guided, but their latency can greatly decrease resulting in short latency CuS (SL-CuS). It is still unclear what triggers these CuS and what are the underlying neural circuits. In this study, we aimed at evaluating the impact of cerebellar pathology on CuS by comparing their characteristics between two groups of patients with bilateral vestibular hypofunction, with or without additional cerebellar dysfunction. We recruited 12 patients with both bilateral vestibular hypofunction and cerebellar dysfunction (BVH-CD group) and 12 patients with isolated bilateral vestibular hypofunction (BVH group). Both groups were matched for age and residual VOR gain. Subjects underwent video head impulse test recording of the horizontal semicircular canals responses as well as recording of visually guided saccades in the step, gap, and overlap paradigms. Latency and gain of the different saccades were calculated. The mean age for BVH-CD and BVH was, respectively, 67.8 and 67.2 years, and the mean residual VOR gain was, respectively, 0.24 and 0.26. The mean latency of the first catch-up saccade was significantly longer for the BVH-CD group than that for the BVH group (204 ms vs 145 ms, p < 0.05). There was no significant difference in the latency of visually guided saccades between the two groups, for none of the three paradigms. The gain of covert saccades tended to be lower in the BVH-CD group than in BVH group (t test; p = 0.06). The mean gain of the 12° or 20° visually guided saccades were not different in both groups. Our results suggest that the cerebellum plays a role in the generation of compensatory SL-CuS observed in BVH patients.

Wernekink commissure syndrome secondary to a rare ‘V’-shaped pure midbrain infarction: a case report and review of the literature

Purpose: Wernekink commissure syndrome is a typical but extremely rare mesencephalic syndrome, and generally presents with bilateral cerebellar dysfunction, diverse oculomotor disorders and occasionally delayed-onset palatal myoclonus or tremor. However, it has been reported infrequently.Methods: We report a case of a 55-year-old man who suffered an acute paramedian midbrain infarction presenting with bilateral cerebellar ataxia, bilateral anterior internuclear ophthalmoplegia and unilateral pseudoabducens palsy, which is confirmed as Wernekink commissure syndrome by magnetic resonance imaging (MRI). We summarized the clinical data of this entity and performed a literature review of 20 previous reports of patients with this syndrome.Results: In combination with previous reports, we found that the most common symptom was bilateral cerebellar ataxia (100%) and other frequent symptoms were oculomotor disorders (81%), delayed palatal myoclonus or tremor (33%) and consciousness dysfunction (33%). Lesions on brain MRI of all patients affected the area of caudal paramedian midbrain (CPM).Conclusion: Bilateral cerebellar ataxia and lesions involved in the area of CPM on MRI are the major features of Wernekink commissure syndrome and should be the necessary conditions of diagnostic criteria. The simultaneous occurrence of bilateral cerebellar ataxia and oculomotor disorders is significant for localization diagnosis. Consciousness dysfunction is also a relatively frequent symptom of this syndrome. Moreover, pseudoabducens palsy might be attributed to a midbrain lesion. Clinicians should be familiar with and early to recognize this unique syndrome to avoid misdiagnosis.

Caudal paramedian midbrain infarction: a clinical study of imaging, clinical features and stroke mechanisms.

Caudal paramedian midbrain infarction (CPMI) is an extremely rare form of ischemic stroke and related clinical studies are scarce. Our aim is to investigate the clinical features, neuroradiological findings and stroke etiology of CPMI. We conducted a retrospective study of 12 patients with CPMI, confirmed by diffusion-weighted MRI from 6820 cerebral infarction patients at our stroke center from January 2012 to August 2018. Experienced neurologists evaluated the clinical manifestations, neuroimaging findings and stroke mechanisms. Twelve patients (11 men, 1 woman) aged 42-81years old met the study inclusion criteria. Seven patients had a unilateral infarction (two right-sided, five left-sided) and five had bilateral infarctions. Sagittal image showed a backward oblique sign in the lower level of the midbrain. Significantly, the bilateral CPMIs presented with a characteristic "V-shaped" appearance in the axial MRI. All patients presented with bilateral cerebellar dysfunction which included dysarthric speech, truncal or gait ataxia and four-limb ataxia. In addition, diplopia and internuclear ophthalmoplegia were frequently encountered in CPMI. Five (41.7%) patients were classified with large artery atherosclerosis, four (33.3%) with small vessel disease, two (16.7%) with cardiogenic embolism, and one (8.3%) with undetermined etiology. CPMI is a rare cerebrovascular disease that destroys the Wernekink commissure, medial longitudinal fasciculi and other adjacent structures. It is characterized by bilateral cerebellar ataxia and eye movement disorders, mainly internuclear ophthalmoplegia. A distinct "V-shaped" radiological feature can be seen in bilateral CPMI patients. The primary mechanisms of unilateral CPMI involve small vessel disease. The underlying stroke mechanisms of bilateral CPMI are either large artery atherosclerosis disease or cardiac embolism.

Wernekink commissure syndrome: a rare midbrain syndrome

Wernekink commissure syndrome is a rare midbrain syndrome, which selectively destroys the Wernekink commissure involving the decussation of superior cerebellar peduncle in midbrain. This syndrome may display a clinical picture: bilateral cerebellar ataxia, eye movement disorders, and palatal tremor. We present two cases of the Wernekink commissure syndrome with acute onset of bilateral cerebellar dysfunction confirmed by magnetic resonance imaging. One patient presented internuclear ophthalmoplegia, but neither showed palatal tremor. It is notable that the bilateral cerebellar dysfunction may be ascribed to midbrain lesion involving the Wernekink commissure, and it may be the sole manifestation of the midbrain lesion.

Brain Fludeoxyglucose F 18 Positron Emission Tomography Hypometabolism in Magnetic Resonance Imaging–Negative X-Linked Adrenoleukodystrophy

A38-YEAR-OLD MAN presented with progressive gait difficulties and urinary and erectile dysfunction of 10 years’ duration. Clinical examination showed right-sided predominant spastic paraparesis, bilateral Babinski signs, hyperreflexia, impaired vibration sensitivity in the distal legs, slight cerebellar dysfunction, and normal cognition. Brain (Figure) and spinal magnetic resonance imaging (MRI) findings were normal, as were copper and vitamins B12 and E levels and results of electromyography and a lumbar puncture. Differential diagnoses included primary lateral sclerosis (although the impaired vibration sensitivity and cerebellar dysfunction were atypical), familial spastic paraparesis, and hereditary leukodystrophy. Brain fludeoxyglucose F 18 positron emission tomography (FDG-PET) showed bilateral hypometabolism (confirmed by z scores between �3 and �4 SDs) in the paramedian frontal, anterior parietal, temporal polar, and cerebellar lobes, making primary lateral sclerosis unlikely. Predominant hypometabolism in the left lower limb motor cortex and both cerebellar lobes corresponded well with the right-sided predominance of the spastic paraparesis and the bilateral cerebellar dysfunction in our pa

Caudal paramedian midbrain syndrome

Caudal midbrain lesions involving the entire decussation of the superior cerebellar peduncles have a distinctive clinical picture: bilateral cerebellar ataxia, eye-movement disorders, and palatal myoclonus. Occasionally, unilateral lesions may produce a similar neurologic picture. To define the clinical and radiologic picture of patients with unilateral lower midbrain ischemic lesions of the decussation of the brachium conjunctivum. Five patients with MRI evidence of unilateral paramedian caudal midbrain infarction were investigated, after the acute stage. All patients had bilateral cerebellar dysfunction characterized by dysarthric speech, truncal and gait ataxia, and dysmetric movements of the limbs, which were more pronounced on one side. Ocular movement abnormalities were observed in three cases. A constant MRI finding was a bilateral inferior olivary degeneration, but only one patient displayed a delayed palatal tremor. A single strategically placed unilateral lesion can cause bilateral dysfunction. In addition, a bilateral cerebellar syndrome can occur with unilateral lesions in the lower midbrain with a wide range of other clinical features.

Impaired rhythm generation in essential tremor

It has been suggested that the cerebellum plays a role in the event-based timing of synchronized repetitive movements. We hypothesized that regularity of rhythmic movements in essential tremor (ET) is impaired, since several lines of evidence suggest the involvement of the cerebellum in the pathomechanism of ET. To test this assumption, we examined the regularity and the maximum frequency of auditory paced repetitive movements at slow and fast stimulus rate in 34 ET patients. Variability of rhythmic finger tapping and alternating hand movements, defined by the standard deviation of movement offset before or after the pacing signal, was significantly higher compared to healthy controls. Timing of rhythmic movements of the two hands was disturbed to the same degree. Our results suggest a severe deficit of event-based rhythm generation on both sides in ET, supporting the presumed bilateral cerebellar dysfunction in this disorder.

Acute transient cerebellar dysfunction and stuttering following mild closed head injury

A wide range of pathologies can cause cerebellar dysfunction but there have been few reports of transient dysfunction after mild head injury. There are none describing stuttering as an acute symptom after such injuries. We report a 12-year-old boy who presented with headache, stuttering speech and truncal and bilateral peripheral cerebellar dysfunction after falling prone from his skateboard. Computed tomographic brain imaging showed normal results. All clinical symptoms and signs had resolved within 24 h obviating further investigation. A follow up clinical interview and examination 4 weeks later revealed no recurrence of cerebellar or speech dysfunction. This is the first reported case of acute transient cerebellar dysfunction and stuttering after mild closed head injury. Neurogenic causes for stuttering are increasingly being recognised.

Grip-load force coordination in cerebellar patients.

The study examined the anticipatory grip force modulations to load force changes during a drawer-opening task. An impact force was induced by a mechanical stop which abruptly arrested movement of the pulling hand. In performing this task, normal subjects generated a typical grip force profile characterized by an initial force impulse related to drawer movement onset, followed by a ramp-like grip force increase prior to the impending load perturbation. Finally, a reactive response was triggered by the impact. In patients with bilateral cerebellar dysfunction, the drawer-opening task was performed with an alternative control strategy. During pulling, grip force was increased to a high (overestimated) default level. The latter suggests that cerebellar patients were unable to adjust and to scale precisely the grip force according to the load force. In addition, the latency between impact and reactive activity was prolonged in the patients, suggesting an impaired cerebellar transmission of the long-latency responses. In conclusion, these data demonstrate the involvement of cerebellar circuits in both proactive and reactive mechanisms in view of predictable load perturbations during manipulative behavior.

Bilateral cerebellar dysfunctions in a unilateral meso-diencephalic lesion.

The clinical syndrome of a 65-year-old patient with a slit-shaped right-sided meso-diencephalic lesion was analysed. A cerebellar syndrome with limb-kinetic ataxia, intention tremor and hypotonicity in all extremities as well as ataxic dysarthria was found. The disruption of the two cerebello-(rubro)-thalamic pathways probably explained the signs of bilateral cerebellar dysfunction. The uncrossed ascending limb of the right, and the crossed one of the left brachium conjunctivum may have been damaged by the unilateral lesion extending between caudal midbrain and dorsal thalamus.