Objective

To investigate the potential therapeutic benefits and tolerability of inhibitory transcranial direct current stimulation (tDCS) on the remediation of visual hallucinations in Charles Bonnet syndrome (CBS).

Design

Randomized, double-masked, placebo-controlled crossover trial.

Participants

Sixteen individuals diagnosed with CBS secondary to visual impairment caused by eye disease experiencing recurrent visual hallucinations.

Intervention

All participants received 4 consecutive days of active and placebo cathodal stimulation (current density: 0.29 mA/cm²) to the visual cortex (Oz) over 2 defined treatment weeks, separated by a 4-week washout period.

Main Outcome Measures

Ratings of visual hallucination frequency and duration following active and placebo stimulation, accounting for treatment order, using a 2 × 2 repeated-measures model. Secondary outcomes included impact ratings of visual hallucinations and electrophysiological measures.

Results

When compared with placebo treatment, active inhibitory stimulation of visual cortex resulted in a significant reduction in the frequency of visual hallucinations measured by the North East Visual Hallucinations Interview, with a moderate-to-large effect size. Impact measures of visual hallucinations improved in both placebo and active conditions, suggesting support and education for CBS may have therapeutic benefits. Participants who demonstrated greater occipital excitability on electroencephalography assessment at the start of treatment were more likely to report a positive treatment response. Stimulation was found to be tolerable in all participants, with no significant adverse effects reported, including no deterioration in preexisting visual impairment.

Conclusions

Findings indicate that inhibitory tDCS of visual cortex may reduce the frequency of visual hallucinations in people with CBS, particularly individuals who demonstrate greater occipital excitability prior to stimulation. tDCS may offer a feasible intervention option for CBS with no significant side effects, warranting larger-scale clinical trials to further characterize its efficacy.

中文翻译：

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经颅直流电刺激治疗 Charles Bonnet 综合征视幻觉

客观的

研究抑制性经颅直流电刺激 (tDCS) 治疗 Charles Bonnet 综合征 (CBS) 视幻觉的潜在治疗益处和耐受性。

设计

随机、双盲、安慰剂对照交叉试验。

参加者

16 名被诊断患有 CBS 的继发于眼病引起的视力障碍的人，他们经历了反复出现的幻视。

干涉

所有参与者在 2 个定义的治疗周内接受连续 4 天的活性和安慰剂阴极刺激（电流密度：0.29 mA/cm ²）到视觉皮层 (Oz)，间隔为 4 周的清除期。

主要观察指标

使用 2 × 2 重复测量模型对主动刺激和安慰剂刺激后的幻视频率和持续时间进行评级，考虑治疗顺序。次要结果包括视觉幻觉和电生理测量的影响评级。

结果

与安慰剂治疗相比，视觉皮层的主动抑制性刺激导致东北视觉幻觉访谈测量的视觉幻觉频率显着降低，效果大小为中等至较大。视觉幻觉的影响措施在安慰剂和主动条件下都有所改善，表明对 CBS 的支持和教育可能具有治疗益处。在治疗开始时脑电图评估中表现出更高枕骨兴奋性的参与者更有可能报告积极的治疗反应。发现所有参与者都可以忍受刺激，没有报告明显的不良反应，包括先前存在的视力障碍没有恶化。

结论

研究结果表明，视觉皮层的抑制性 tDCS 可能会降低 CBS 患者出现幻视的频率，尤其是那些在刺激前表现出更强枕叶兴奋性的个体。tDCS 可能为 CBS 提供一种可行的干预选择，没有明显的副作用，需要更大规模的临床试验来进一步表征其功效。