Reduced power and phase-locking values were accompanied by thalamus, putamen, and hippocampus atrophy in Parkinson's disease with mild cognitive impairment: an event-related oscillation study.

Parkinson's disease (PD) is a multifaceted neurodegenerative disorder accompanied by mild cognitive impairment (MCI) as a crucial nonmotor manifestation. Event-related oscillations (EROs) are suggested to reflect cognitive status associated with subcortical structures in neurodegenerative conditions. In this study, 36 individuals with PD-MCI and 32 PD-CN were compared with 60 healthy control (HC) participants using visual EROs by measures of event-related spectral perturbation and inter-trial coherence, along with subcortical gray matter volumes based on the FIRST algorithm. Cross-correlations among electrophysiological, neuropsychological, and structural parameters were investigated exploratively. Both PD-MCI and PD-CN patients had diminished delta and alpha phase-locking than HC, however, electrophysiological abnormalities were more pronounced in PD-MCI over frontal, central, parietal, and temporal locations in almost all frequency bands, accompanied by bilateral thalamus, hippocampus, and right putamen atrophy. PD-CN had lower hippocampal volumes than HC, without exhibiting any subcortical differences from PD-MCI. Lastly, EROs showed low-to-high correlations with structural and neuropsychological measures. These findings may highlight the complex interplay between electrophysiological, neuropsychological, and structural parameters in detected abnormalities of PD-CN and PD-MCI.

Functional magnetic resonance imaging of the effects of low-frequency transcutaneous electrical nerve stimulation on central pain modulation: a double-blind, placebo-controlled trial.

OBJECTIVES: Transcutaneous electrical nerve stimulation (TENS) is an analgesic current that is used in many acute and chronic painful states. The aim of this study was to investigate central pain modulation by low-frequency TENS. METHODS: Twenty patients diagnosed with subacromial impingement syndrome of the shoulder were enrolled in the study. Patients were randomized into 2 groups: low-frequency TENS and sham TENS. Painful stimuli were delivered during which functional magnetic resonance imaging scans were performed, both before and after treatment. Ten central regions of interest that were reported to have a role in pain perception were chosen and analyzed bilaterally on functional magnetic resonance images. Perceived pain intensity during painful stimuli was evaluated using visual analog scale (VAS). RESULTS: In the low-frequency TENS group, there was a statistically significant decrease in the perceived pain intensity and pain-specific activation of the contralateral primary sensory cortex, bilateral caudal anterior cingulate cortex, and of the ipsilateral supplementary motor area. There was a statistically significant correlation between the change of VAS value and the change of activity in the contralateral thalamus, prefrontal cortex, and the ipsilateral posterior parietal cortex. In the sham TENS group, there was no significant change in VAS value and activity of regions of interest. DISCUSSION: We suggest that a 1-session low-frequency TENS may induce analgesic effect through modulation of discriminative, affective, and motor aspects of central pain perception.

Unilateral acute retinal necrosis in a multiple sclerosis patient treated with high-dose systemic steroids.

A 50-year-old man with multiple sclerosis developed unilateral acute retinal necrosis following a long-term systemic corticosteroid administration for treatment of an attack of paraparesis. The patient was treated with systemic acyclovir, aspirin, oral steroids and topical cyclopentolate and prednisolone acetate for almost 3 months. Pars plana vitrectomy and 360° endolaser photocoagulation posterior to necrotic retinal areas were performed a week after the initial diagnosis. Varicella zoster DNA was confirmed by PCR analysis in the vitreous sample. Two months later, pars plana vitrectomy with silicone oil injection was performed successfully to treat complicated retinal detachment. Careful peripheral fundus examination is essential when acute unexplained visual loss is noted in patients receiving systemic corticosteroids to exclude acute retinal necrosis syndrome.