Okada Yukihiro, Murata Miho, Toda Tatsushi
Division of Neurology, Kobe University Graduate School of Medicine, Chuoku, Kobe, Japan.
Department of Neurology, National Center Hospital of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
Kobe J Med Sci. 2015 Apr 27;61(5):E144-54.
The effects of levodopa on articulatory dysfunction in patients with Parkinson's disease remain inconclusive. This study aimed to investigate the effects of levodopa on isolated vowel articulation and motor performance in patients with moderate to severe Parkinson's disease, excluding speech fluctuations caused by dyskinesia.
21 patients (14 males and 7 females) and 21 age- and sex- matched healthy subjects were enrolled. Together with motor assessment, the patients phonated five Japanese isolated vowels (/a/, /i/, /u/, /e/, and /o/) 20 times before and 1 h after levodopa treatment. We made the frequency analysis of each vowel and measured the first and second formants. From these formants we constructed the pentagonal vowel space area which should be the good indicator for articulatory dysfunction of vowels. In control subjects, only speech samples were analyzed. To investigate the sequential relationship between plasma levodopa concentrations, motor performances, and acoustic measurements after treatment, entire drug cycle tests were performed in 4 patients.
The pentagonal vowel space area was significantly expanded together with motor amelioration after levodopa treatment, although the enlargement is not enough for the space area of control subjects. Drug cycle tests revealed that sequential increases or decreases in plasma levodopa levels after treatment correlated well with expansion or decrease of the vowel space areas and improvement or deterioration of motor manifestations.
Levodopa expanded the vowel space area and ameliorated motor performance, suggesting that dysfunctions in vowel articulation and motor performance in patients with Parkinson's disease are based on dopaminergic pathology.
左旋多巴对帕金森病患者发音功能障碍的影响尚无定论。本研究旨在探讨左旋多巴对中重度帕金森病患者孤立元音发音及运动表现的影响，排除异动症引起的言语波动。
招募21例患者（14例男性和7例女性）及21名年龄和性别匹配的健康受试者。在运动评估的同时，患者在左旋多巴治疗前和治疗后1小时分别对五个日语孤立元音（/a/、/i/、/u/、/e/和/o/）进行20次发声。我们对每个元音进行频率分析并测量第一和第二共振峰。根据这些共振峰构建五边形元音空间面积，该面积应是元音发音功能障碍的良好指标。在对照受试者中，仅对语音样本进行分析。为了研究治疗后血浆左旋多巴浓度、运动表现和声学测量之间的顺序关系，对4例患者进行了完整的药物周期测试。
左旋多巴治疗后，五边形元音空间面积随运动改善而显著扩大，尽管扩大程度不足以达到对照受试者的空间面积。药物周期测试显示，治疗后血浆左旋多巴水平的顺序升高或降低与元音空间面积的扩大或缩小以及运动表现的改善或恶化密切相关。
左旋多巴扩大了元音空间面积并改善了运动表现，提示帕金森病患者的元音发音功能障碍和运动表现基于多巴胺能病理改变。
