Olfactory dysfunction in early Parkinson’s disease is associated with short latency afferent inhibition reflecting central cholinergic dysfunction

Publication date: Available online 18 March 2017
Source:Clinical Neurophysiology
Author(s): Eungseok Oh, Jinse Park, Jinyoung Youn, Ji Sun Kim, Suyeon Park, Wooyoung Jang
ObjectiveOur study aimed to determine whether the short latency afferent inhibition (SAI) response could be associated with the severity of olfactory dysfunction in PD patients.MethodsA total of 71 PD patients and 20 controls were enrolled. All PD patients were classified into 3 groups by the severity of the olfactory deficit. Single-pulse transmagnetic stimulation (TMS) parameters and SAI were assessed.ResultsThe integrated SAI in the PD with anosmia and PD with hyposomia groups was significantly less inhibited than that in the PD with normosmia and control groups [64.79 {Interquartile range(IQR): 59.96, 71.33}, 84.79 {IQR: 75.03, 90.63} versus 36.72 {IQR: 32.28, 48.33}, 42.15 {IQR: 34.60, 44.96}, respectively]. In PD subjects, the severity of olfactory dysfunction also showed a significant negative correlation with the SAI response (r = -0.829, p < 0.001).ConclusionsConsidering that the SAI response partly reflects central cholinergic dysfunction and that our study shows a relationship between the SAI response and the severity of olfactory dysfunction in PD, our findings indicate that cholinergic dysfunction could possibly contribute to the pathogenesis of olfactory dysfunction in early PD.SignificanceSAI could be a useful marker to detect severe olfactory dysfunction in PD.



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