This study aimed to clarify associations of clinical and neuropsychological features and change in regional cerebral blood flow (rCBF) on ¹²³I-IMP-SPECT in patients with Parkinson’s disease (PD) who developed dementia. Sixty-one PD patients (mean age, 65.9 ± 8.6 years; mean disease duration, 11.0 ± 11.0 years) were recruited and followed-up for two years. Clinical and neuropsychological characteristics, and rCBF from SPECT were compared between PD patients who developed dementia (PDD+) and those who remained undemented (PDD−). Thirty-eight PD patients (62.3%) were diagnosed with PD-MCI at baseline. During follow-up, 22 PD patients (36%) developed dementia (PDD+). Univariate logistic regression models showed that Hoehn and Yahr scale 4 (odds ratio [OR] 5.85; 95% confidence interval [CI] 1.35–30.75]), visual hallucination (OR 5.95; 95%CI 1.67–25.4]), and PD-MCI (OR 6.47; 95%CI 1.57–39.63]) represented a significant risk factor for PDD+. Among neuropsychological parameters, WAIS (Wechsler Adult Intelligence Scale)-III block design (OR 6.55; 95%CI 1.66–29.84), letter number sequencing (OR 7.01; 95%CI 1.65–36.64), digit-symbol coding (OR 3.90; 95%CI 1.13–14.2), Wechsler Memory Scale, revised (WMS-R) visual paired associates II (delayed recall) (OR 4.68; 95%CI 1.36–17.36), Logical memory I (immediate recall) (OR 8.30; 95%CI 1.37–90.89), Logical memory II (delayed recall) (OR 6.61; 95%CI 1.35–44.33), Visual reproduction I (immediate recall) (OR 7.67; 95%CI 2.11–31.40), and Visual reproduction II (delayed recall) (OR 5.64; 95%CI 1.62–21.47) were significant risk factors. Decreased rCBF assessed using the general linear model (two-sample t-test) by SPM8 was observed in the left precuneus (0, −66, 16), right cuneus (6, −76, 30), and left angular gyrus (−46, −74, 32) in PDD+ compared with PDD− patients. Collectively, we have here shown that clinical and neuropsychological characteristics as well as changes to rCBF in PD patients who converted to PDD+. These features should be carefully monitored to detect the development of dementia in PD patients.

A 55-year-old woman suffered from diplopia and occipital pain after shoveling snow. She was diagnosed with the right vertebral artery dissecting aneurysm at the level of the axial vertebra and repeatedly had cerebral infarctions in the posterior circulation. She had subluxation of the atlantoaxial vertebra as an underlying disease. Right vertebral angiogram with the head rotated to the left showed the right vertebral artery occlusion and left vertebral angiogram with the head rotated to the right showed stenosis at the C1–C2 level, leading to the diagnosis of Bow hunter’s stroke. After wearing a cervical collar and taking 100 ‍mg of aspirin, she had no recurrence of cerebral infarction and later underwent C1–C2 posterior fusion to prevent the recurrence of cerebral infarction. She finished taking aspirin 6 months after the surgery, and there has been no recurrence of cerebral infarction. We report here a case of Bow hunter’s stroke, a rare disease, with good clinical outcomes after C1–C2 posterior fusion.

Herein, we present the case of a 76-year-old man diagnosed with an iliopsoas abscess 3 months prior and consequently administered metronidazole. The patient visited our facility complaining of difficulty in speaking and feeling unsteady when walking. Neurological findings showed dysarthria, nystagmus, and bilateral cerebellar ataxia. Head MRI-FLAIR demonstrated symmetrical hyperintensities in the bilateral cerebellar dentate nuclei, red nucleus, periaqueductal of the midbrain, periventricular third ventricle, and the corpus callosum. Although Wernicke’s encephalopathy was among the differential diagnoses based on the imaging findings, the thiamine level was normal and improvement in symptoms and hyperintensity on FLAIR within 5 days of discontinuing metronidazole led to the diagnosis of metronidazole-induced encephalopathy. Although there were many similarities in the imaging findings of metronidazole-induced encephalopathy and Wernicke’s encephalopathy, Metronidazole-induced encephalopathy should be initially considered when midbrain red nucleus lesions are observed.

A 26-year-old woman presented with a seven-month history of weakness in her left upper limb, progressing to difficulty lifting her arms within a few weeks. Her symptoms progressed with fluctuations. For the past three months, she has been unable to stand due to weakness in her proximal lower limbs. Nerve conduction studies did not show any definite conduction block or abnormal sensory conduction, but motor conduction studies showed a slight prolongation of the terminal latency and a decrease in the frequency of the F-wave. A magnetic fatigue test indicated a proximal conduction block. Her symptoms were rapidly resolved with intravenous immunoglobulin treatment, leading to a diagnosis of chronic immune-mediated neuropathy, met both criteria for multifocal motor neuropathy (MMN) and motor chronic inflammatory demyelinating polyneuropathy (CIDP). Our case highlights the utility of the magnetic fatigue test in detecting conduction blocks and its role in differentiating between MMN and motor CIDP.

Here we present the case of a 23-year-old female with a history of onychomycosis and oral thrush since childhood. She presented with a gradual onset of headache, and cerebrospinal fluid (CSF) analysis on admission revealed an elevated mononuclear cell count. Hydrocephalus was observed on brain MRI. Candida albicans (C. albicans) was detected in the CSF, and antifungal treatment was initiated to diagnose of Candida meningitis. Due to an insufficient therapeutic response, intraventricular administration of liposomal amphotericin B initiated; however, the lesions persisted. Subsequently, the patient experienced repeated occlusions of the ventriculoperitoneal shunt tube, ultimately dying from a bacterial shunt infection. Autopsy findings revealed diffuse fungal proliferation on the surface of the brainstem and ventricular walls. Genetic testing confirmed a diagnosis of CARD9 deficiency. Although CARD9 deficiency is a rare disease, genetic testing should be considered when primary immunodeficiency is suspected.

A 32-year-old male presented with unilateral orbital-temporal pulsatile headache, followed by fever in the 38°C range and nausea. The patient experienced two episodes of transient dysarthria and tinnitus, each lasting several minutes. MRI revealed swelling of the left cerebral cortex, enhancement of the leptomeninges, dilation of the left middle cerebral artery, and subcortical FLAIR hypointensity. The clinical presentation and MRI findings raised suspicions of myelin oligodendrocyte glycoprotein (MOG) antibody-associated cortical encephalitis. After two courses of steroid pulse therapy, the patient’s headache subsided, and there was a significant improvement in the swelling of the left cerebral cortex. Subsequently, serum MOG antibody positivity was confirmed. While unilateral cortical FLAIR hyperintensity and increased blood flow can be observed in various diseases, MOG antibody-associated cortical encephalitis is notably characterized by subcortical FLAIR hypointensity, a finding more frequently observed in this condition compared to other diseases. In this case, the findings were useful for early diagnosis and intervention.

Herpes simplex virus (HSV) infections necessitate careful management of urinary dysfunction and retention, which are underestimated conditions. Here, we present a rare case of HSV encephalomyeloradiculitis in a 76-year-old man, whose initial symptoms included urinary dysfunction and retention that alone lasted for approximately 1 week. Unlike in meningoencephalitis, high fever and headache were absent; however, the patient subsequently developed cauda equina syndrome and consciousness disturbance. Gadolinium-enhanced spinal MRI suggested enhanced cauda equina at the L2/3 level. Upon admission, he was treated for meningoencephalitis with acyclovir and steroid pulse therapy. Subsequent cerebrospinal fluid analysis result was positive for HSV DNA. A ‍brain MRI conducted 1 week after admission displayed high-intensity lesions in the white matter of the right temporal lobe, confirming HSV encephalomyeloradiculitis. These treatments were highly effective and gradually improved the patient’s condition. He was discharged 1 month after hospitalization, and the urinary catheter was removed 2 weeks later. HSV infections can cause life-threatening encephalomyeloradiculitis. Therefore, both neurologists and urologists must pay attention to their occurrence and characteristics in clinical settings.

A 76-year-old woman with a 2-year history of Parkinson’s disease presented with dropped head, which had developed rapidly after she had been prescribed donepezil hydrochloride (DNP) at 3 ‍mg/day. After one month of medication, the extent of the head drop reached 90°. Examination revealed hypertrophy of the left sternocleidomastoid muscle, but no weakness of the extensor muscles in the cervical region. Surface electromyography demonstrated co-‍contraction of the sternocleidomastoid and splenius capitus muscles during head flexion and extension. DNP was withdrawn, resulting in immediate amelioration of the head drop, and complete resolution was achieved after two months. Although head drop is often seen in patients with Parkinson’s disease, few previous reports have documented DNP as a causative factor. If patients with Parkinson’s disease develop head drop, it is important to investigate any history of DNP medication.

We report a case of numb chin syndrome caused by a small cortical infarction in the postcentral gyrus. A 67-year-old man suddenly developed numbness in his right lower lip and the chin. There were no apparent abnormal neurological symptoms other than numbness. MRI revealed a fresh small infarction in the left postcentral gyrus, which corresponds with the somatosensory area of the lower lip and the chin drawn by Penfield and Rasmussen. MRA showed no significant stenosis in the main trunk of the cerebral arteries. A soft plaque with irregular wall was detected in the left carotid bifurcation on carotid ultrasonography. Based on these findings, we diagnosed him with arteriogenic cerebral embolism, and started antiplatelet therapy. A small infarction in the postcentral gyrus can cause numbness in the lower lip and the chin, which can be considered numb chin syndrome. Numb chin syndrome due to thalamic infarction has been reported previously. The present case is the first numb chin syndrome caused by a small cortical infarction in the postcentral gyrus.