Ataxia is not only due to cerebellar lesions, but also due to non-cerebellar lesions such as those in the brain, spinal cord, dorsal root (DR), peripheral nerve. In this article, optic ataxia is excluded and ‘vestibular ataxia’ is briefly referred. Non-cerebellar ataxias are generically called sensory ataxia or posterior column ataxia. However, since non-cerebellar lesions, e.g. frontal lobe lesions, may develop “cerebellar-like ataxia” (Hirayama, 2010). At the same time, non-posterior column lesions, e.g. parietal lobe lesion, can show “posterior column-like ataxia”. From these viewpoints, I here describe various non-cerebellar ataxia in some disorders such as tabes dorsalis and sensory neuropathies and emphasize a role of a peripheral sensory input to the cerebellum via the DR ganglia and spinocerebellar tract for sensory ataxia because there is the International Consensus (2016) that the ataxia in Miller Fisher syndrome is suggested cerebellar-like clinicophysiologically.

Objective: To clarify the clinical and long-term characteristics of multifocal motor neuropathy (MMN). Methods: We retrospectively evaluated data from 8 consecutive MMN patients in Yamaguchi University Hospital from 2005 to 2020. Clinical information including dominant hand, occupations, hobbies, nerve conduction data, protein level in cerebrospinal fluid (CSF), responsiveness to intravenous immunoglobulin (IVIg) therapy as initial therapy as well as maintenance therapy were collected. Results: Unilateral upper limb was initially affected in all patients and a dominant upper extremity was affected in six of them. Seven patients had occupations or hobbies which were associated with overuse of their dominant upper extremity. CSF protein level was normal or slightly elevated. Nerve conduction studies showed conduction blocks in 4 cases. Effectiveness of IVIg treatment as initial therapy was observed in all patients. Maintenance therapy was not needed in 2 patients because of mild symptoms with stable clinical course. Long-term maintenance therapy with immunoglobulin was effective in 5 patients during the follow-up period. Conclusion: Dominant upper extremity was frequently affected and most patients had job or habit associated with its overuse, suggesting that physical overload induces inflammation or demyelination in MMN. IVIg was commonly effective as both introduction and long-term maintenance therapies. Complete remission was achieved after several IVIg treatments in some patients.

A 42 years old female suffered from systemic lupus erythematosus (SLE) about 20 years ago. While steroid was tapered for a steroid-induced psychiatric disorder, she presented with an acute confusional state and was diagnosed with neuropsychiatric SLE (NPSLE). MRI showed acute infarction mainly in the cortex of the right temporal lobe and MRA demonstrated dynamic subacute morphological changes such as stenosis and dilation in several major intracrainal arteries. The right vertebral artery diffusely dilated and subsequently formed an aneurysm in a week. Contrast-enhanced MRI vessel-wall imaging showed a remarkable enhancement of the aneurysm wall, which might indicate an unstable unruptured aneurysm. The prompt introduction of intravenous cyclophosphamide improved both clinical and radiological signs. Our case indicates that intensive immunosuppressive treatments should be considered in NPSLE patients with varying vasospasm and aneurysm, indicating exacerbated disease activity.

A 37-year-old man who had a low grade fever for 5 days admitted to our hospital due to disturbance of consciousness and seizure. Brain MRI showed abnormal hyperintensity in the bilateral temporal lobes, cortical and subcortical lesions on fluid-attenuated inversion recovery image. Treponemal and non-treponemal specific antibodies were positive in serum and cerebrospinal fluid, therefore he was diagnosed as having neurosyphilis. Treatment with intravenous penicillin G and metylpredonisolone improved his clinical symptons, imaging abnormalities and CSF findings. Patients of neurosyphilis with mesiotemporal encephalitis show common features such as young age, HIV-negative, subacute cognitive impairment and seizure, as seen in our case. Early diagnosis of neurosyphilis and appropriate treatment make clinical improvement, however the clinical diagnosis of neurosyphilis is sometime difficult because most patients present with disturbance of consciousness or seizure. The possibility of neurosyphilis should be considered when MRI results indicate temporal abnormalities.

We present varicella-zoster virus (VZV) infection with concomitant lower cranial polyneuropathy in the absence of meningeal symptoms. Physical examination showed involvement of cranial nerves IX and X in Case 1 and of cranial nerves IX, X, and XI in Case 2. Cerebrospinal fluid (CSF) analysis revealed mild lymphocytic pleocytosis, normal protein levels, and absence of VZV-DNA based on polymerase chain reaction (PCR) analysis. Serum anti-VZV antibody testing showed positive results in both cases, which confirmed the diagnosis of VZV infection. VZV infection accompanied by lower cranial polyneuropathy is rare; therefore, it is important to consider VZV reactivation as an etiopathogenetic contributor to pharyngeal palsy and hoarseness. We emphasize the importance of serological analysis for precise diagnosis in VZV infection with multiple lower cranial nerve palsies because the VZV-DNA PCR test may show negative results in patients without meningitis symptoms or in those with normal CSF protein levels.