Galvanic vestibular stimulation (GVS) activates the vestibular afferents, and these changes in vestibular input exert a strong influence on the subject's posture or standing balance. In patients with Parkinson's disease (PD), vestibular dysfunction might contribute to postural instability and gait disorders. Current intensity was increased to 0.7 mA, and the current was applied to the patients for 20 minutes. To perform a sham stimulation, the current intensity was increased as described and then decreased to 0 mA over the course of 10 seconds. The patient's status was recorded continuously for 20 minutes with the patient in the supine position. Three out of 5 patients diagnosed with PD with postural instability and/or abnormal axial posture showed a reduction in postural instability after GVS. The score for item 12 of the revised Unified Parkinson's Disease Rating Scale part 3 was decreased in these patients. The mechanism of postural instability is complex and not completely understood. In 2 out of the 5 patients, postural instability was not changed in response to GVS. Nonetheless, the GVS-induced change in postural instability for 3 patients in our study suggests that GVS might be a therapeutic option for postural instability.

Danon disease, an X-linked dominant cardioskeletal myopathy, is caused by primary deficiency of lysosome-associated membrane protein-2 (LAMP-2). To clarify the clinicopathological features and management, we performed the first nationwide, questionnaire-based survey on Danon disease in Japan. A total of 39 patients (17 males, 22 females) from 20 families were identified in the analysis. All patients had cardiomyopathy. Of the 21 patients who died, 20 (95%) died of cardiac failure or sudden cardiac arrest. Most patients had hypertrophic cardiomyopathy. Wolf–Parkinson–White syndrome was present at a comparatively high incidence (54% in males, 22% in females). Only one female patient received a heart transplant, which is the most effective therapy. Histopathologically, all male patients showed autophagic vacuoles with sarcolemmal features in muscle. Half of the probands showed de novo mutations. Male patients showed completely absent LAMP-2 expression in muscle. In contrast, female patients showed decreased LAMP-2 expression, which is suggested to reflect LAMP-2 haploinsufficiency due to a heterozygous null mutation. In conclusion, Danon disease is an extremely rare muscular disorder in Japan. Cardiomyopathy is the most significant prognostic factor and the main cause of death. Our findings suggest that the present survey can extend our understanding of the clinical features of this rare disease.

Othello syndrome (OS) is a type of paranoid delusional jealousy, characterized by the false absolute certainty of the infidelity of a partner. Because OS has infrequently occurred in patients with PD, the characteristics of OS in PD remain unclear. We reviewed the clinical characteristics of this syndrome in PD. We reviewed 67 patients who had PD with OS. OS was more common in men (45 patients) than in women (22 patients), and it frequently occurred in middle-aged patients. Until the onset of OS, the duration of PD (range, 2 to 19.8 years) and the duration of treatment with PD medications (range, 2 months to 18.5 years) varied. At the onset of OS, cognition was preserved in most patients. 42 of 47 patients had other psychiatric disorders in addition to OS, and 5 patients had isolated OS. Persecutory or other paranoid delusions developed in 34 patients with OS. OS was associated with PD medication in 25 of 26 patients, especially in patients used the dopamine agonists. The dose of the PD medication associated with OS was decreased or these drugs were withdrawn to facilitate the treatment of OS. In most patients, OS disappeared or the severity of OS was reduced. OS is infrequent in patients with PD, but is likely to be easily detected because OS is commonly accompanied by persistent paranoid and sexual delusions. When clinicians encounter such patients, the withdrawal or reduction of dopamine agonists should be attempted, and if necessary, additional treatment with clozapine is recommended.