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We aimed to assess whether allelic variants of dopamine receptor, glutamate receptor, and serotonin transporter genes are associated with the appearance of impulse control and related behaviors (ICRB) in Parkinson's disease (PD) with dopamine replacement therapy (DRT). We surveyed ICRB in consecutive Korean patients with PD who were treated with stable DRT using modified Minnesota Impulsive Disorders Interview over a period of 4 months. In the 404 patients who completed the interview and the 559 Korean healthy normal controls, genotyping was performed for variants of the DRD3 p.S9G, DRD2 Taq1A, GRIN2B c.366C>G, c.2664C>T and c.-200T>G, and the promoter region of the serotonin transporter gene (5-HTTLPR). Behavioral abnormalities suggestive of ICRB including compulsive buying, gambling, sexual behavior and eating, and punding, were present in 14.4% of the patients. Variants of DRD2 and 5-HTTLPR were not associated with the risk of developing ICRB. However, the AA genotype of DRD3 p.S9G and the CC genotype of GRIN2B c.366C>G were more frequent in patients with ICRB than in nonaffected patients (odds ratio [OR] = 2.21, P = 0.0094; and 2.14, P = 0.0087, after adjusting for age and sex). After controlling for clinical variables in the multivariate analysis, carriage of either AA genotype of DRD3 or CC genotype of GRIN2B was identified as an independent risk factor for ICRB (adjusted OR: 2.57, P = 0.0087). Variants of DRD3 p.S9G and GRIN2B c.366C>G may be associated with the appearance of ICRB in PD.

Asymmetry of the multifidus muscles as seen in MRI was a useful finding to assess patients who had unilateral lumbosacral radiculopathy with HIVD. This may reflect the denervation of multifidus muscles in lumbosacral radiculopathy.

Defective visual information processing from both central and peripheral pathways is one of the suggested mechanisms of visual hallucination in Parkinson's disease (PD). To investigate the role of retinal thinning for visual hallucination in PD, we conducted a case-control study using spectral domain optical coherence tomography. We examined a representative sample of 61 patients with PD and 30 healthy controls who had no history of ophthalmic diseases. General ophthalmologic examinations and optical coherence tomography scans were performed in each participant. Total macular thickness and the thickness of each retinal layer on horizontal scans through the fovea were compared between the groups. In a comparison between patients with PD and healthy controls, there was significant parafoveal inner nuclear layer thinning, whereas other retinal layers, including the retinal nerve fiber layer, as well as total macular thicknesses were not different. In terms of visual hallucinations among the PD subgroups, only retinal nerve fiber layer thickness differed significantly, whereas total macular thickness and the thickness of other retinal layers did not differ. The retinal nerve fiber layer was thinnest in the group that had hallucinations without dementia, followed by the group that had hallucinations with dementia, and the group that had no hallucinations and no dementia. General ophthalmologic examinations did not reveal any significant correlation with hallucinations. There were no significant correlations between retinal thicknesses and duration or severity of PD and medication dosages. The results indicate that retinal nerve fiber layer thinning may be related to visual hallucination in nondemented patients with PD. Replication studies as well as further studies to elucidate the mechanism of thinning are warranted.