Manganelli Fiore, Vitale Carmine, Santangelo Gabriella, Pisciotta Chiara, Iodice Rosa, Cozzolino Autilia, Dubbioso Raffaele, Picillo Marina, Barone Paolo, Santoro Lucio
Department of Neurological Sciences, University Federico II of Naples, Naples, Italy.
Brain. 2009 Sep;132(Pt 9):2350-5. doi: 10.1093/brain/awp166. Epub 2009 Jul 7.
Visual hallucinations (VHs) represent a frequent and disturbing complication of Parkinson's disease. Evidence suggests that VH can be related to central cholinergic dysfunction. Short-latency afferent inhibition (SAI) technique gives the opportunity to test an inhibitory cholinergic circuit in the human cerebral motor cortex. This inhibition of motor-evoked potentials can be observed when transcranial magnetic stimulation is delivered with a delay ranging from 2 to 8 ms, after a peripheral nerve afferent input has reached the somatosensory cortex. We applied SAI technique in 10 non-demented patients with Parkinson's disease with VHs, in 12 non-demented patients with Parkinson's disease without VHs (NVH-pts) and in 11 age-matched normal controls. All patients with Parkinson's disease underwent a battery of neuropsychological tests to assess frontal and visuospatial functions, memory and attention. SAI was significantly reduced in patients with VHs compared with controls and patients without VHs. Neuropsychological examination showed a mild cognitive impairment in 16 out of 22 patients with Parkinson's disease. In addition, we found that in our patients with VHs, performance of some tasks evaluating visuospatial functions and attentional/frontal lobe functions was significantly more impaired than in patients without VHs. SAI abnormalities, presence of VH and neuropsychological results strongly support the hypothesis of cholinergic dysfunction in some patients with Parkinson's disease, who will probably develop a dementia. A follow-up study of our patients is required to verify whether SAI abnormalities can predict a future severe cognitive decline. Moreover, SAI can also be very useful to follow-up the efficacy of anti-cholinesterase therapies.
视幻觉（VHs）是帕金森病常见且令人困扰的并发症。有证据表明，视幻觉可能与中枢胆碱能功能障碍有关。短潜伏期传入抑制（SAI）技术为检测人类大脑运动皮层中的胆碱能抑制回路提供了机会。当在周围神经传入输入到达体感皮层后，以2至8毫秒的延迟进行经颅磁刺激时，可观察到运动诱发电位的这种抑制。我们对10例患有视幻觉的非痴呆帕金森病患者、12例无视幻觉的非痴呆帕金森病患者（NVH患者）以及11名年龄匹配的正常对照者应用了SAI技术。所有帕金森病患者均接受了一系列神经心理学测试，以评估额叶和视觉空间功能、记忆和注意力。与对照组和无视幻觉的患者相比，有视幻觉的患者SAI显著降低。神经心理学检查显示，22例帕金森病患者中有16例存在轻度认知障碍。此外，我们发现，在我们患有视幻觉的患者中，一些评估视觉空间功能和注意力/额叶功能的任务表现比无视幻觉的患者明显受损更严重。SAI异常、视幻觉的存在以及神经心理学结果有力地支持了一些帕金森病患者存在胆碱能功能障碍的假说，这些患者可能会发展为痴呆。需要对我们的患者进行随访研究，以验证SAI异常是否能预测未来严重的认知衰退。此外，SAI对于随访抗胆碱酯酶疗法的疗效也可能非常有用。
