最近一項(xiàng)研究發(fā)現(xiàn)嗅覺(jué)受損或可與重癥肌無(wú)力相關(guān)。嗅覺(jué)和味覺(jué)改變是阿爾茲海默病和帕金森病的早期表現(xiàn),，但現(xiàn)在,，來(lái)自賓夕法尼亞大學(xué)的研究顯示嗅覺(jué)受損和重癥肌無(wú)力存在一定的相關(guān)性。該研究結(jié)果發(fā)表在最新一期 PLOS ONE雜志上,。
賓夕法尼亞大學(xué)嗅覺(jué)和味覺(jué)研究中心主任,、高級(jí)研究員Richard Doty博士介紹說(shuō)：“該項(xiàng)研究首次闡述了重癥肌無(wú)力與嗅覺(jué)系統(tǒng)顯著的功能障礙相關(guān)，與阿爾茲海默病和帕金森病伴發(fā)嗅覺(jué)障礙的情況相似,。研究結(jié)果強(qiáng)力證明了重癥肌無(wú)力不僅僅只是單純的外周神經(jīng)系統(tǒng)性疾病,，而且可能與大腦也密切相關(guān)。”
普遍觀念認(rèn)為重癥肌無(wú)力僅僅是外周神經(jīng)系統(tǒng)疾病這,，部分原因是由于在該病患者大腦中沒(méi)有發(fā)現(xiàn)明顯的病理改變.雖有行為學(xué)和生理學(xué)證據(jù)支持重癥肌無(wú)力伴有中樞神經(jīng)系統(tǒng)改變,但由于結(jié)果不具有重復(fù)性而未予重視.例如,有研究發(fā)現(xiàn)重癥肌無(wú)力相關(guān)性語(yǔ)言記憶障礙,但也有研究并不支持.此外,科學(xué)家們持續(xù)報(bào)道重癥肌無(wú)力相關(guān)性中樞神經(jīng)功能障礙,比如視覺(jué),、聽(tīng)覺(jué)損害.另外，重癥肌無(wú)力患者腦電圖檢查也有異常改變,，其腦脊液中還可檢測(cè)出重癥肌無(wú)力相關(guān)抗體,。
為了進(jìn)一步探索中樞神經(jīng)系統(tǒng)在重癥肌無(wú)力中的作用,，Richard Doty博士和他的同事們進(jìn)行了嗅覺(jué)試驗(yàn)，該實(shí)驗(yàn)曾被用于評(píng)估嗅覺(jué)與其它一些神經(jīng)變性性疾病 的潛在聯(lián)系,。Richard Doty博士說(shuō)：“我們的嗅覺(jué)與很多大腦功能都有著直接的聯(lián)系,，嗅覺(jué)可作為其它復(fù)雜大腦神經(jīng)環(huán)路一個(gè)良好模型系統(tǒng)。對(duì)嗅覺(jué)的認(rèn)識(shí)與否,，將會(huì)拓寬對(duì)大腦功能以及起源自大腦的疾病的理解,。
在Richard Doty博士進(jìn)行的研究中，納入了27名重癥肌無(wú)力患者,，27例性別和年齡正常人群匹配對(duì)照者,，11名多發(fā)性肌炎患者。 所有研究對(duì)象均進(jìn)行嗅覺(jué)識(shí)別檢測(cè)(UPSIT)和圖形識(shí)別檢測(cè)試驗(yàn),。研究人員發(fā)現(xiàn)重癥肌無(wú)力患者的嗅覺(jué)識(shí)別檢測(cè)評(píng)分明顯低于同性別年齡對(duì)照組和多發(fā)性肌炎患者,。重癥肌無(wú)力患者中，只有15%患者在進(jìn)行該實(shí)驗(yàn)之前已知存在嗅覺(jué)問(wèn)題,。
Doty博士說(shuō)：“重癥肌無(wú)力患者與正常對(duì)照組比,，存在顯著的嗅覺(jué)功能障礙，這一點(diǎn)不能被任何其它生理或者認(rèn)知功能差異所解釋,。盡管目前我們還在探尋重癥肌無(wú)力患者伴嗅覺(jué)障礙的生理學(xué)基礎(chǔ),，但有一點(diǎn)需要強(qiáng)調(diào)的是：該項(xiàng)研究中發(fā)現(xiàn)的嗅覺(jué)障礙與其它中樞神經(jīng)系統(tǒng)疾病伴發(fā)嗅覺(jué)障礙程度相似，包括阿爾茨海默病和帕金森病,。“
根據(jù)以上研究結(jié)果,，作者認(rèn)為有必要進(jìn)行更大規(guī)模試驗(yàn)探尋重癥肌無(wú)力的中樞神經(jīng)系統(tǒng)病變基礎(chǔ)，如有可能,，嗅覺(jué)檢測(cè)將有助于該病的識(shí)別和進(jìn)展監(jiān)測(cè),。他們還建議臨床醫(yī)師應(yīng)該與重癥肌無(wú)力患者討論嗅覺(jué)障礙情況，警醒患者避免一些環(huán)境災(zāi)害例如食物燒糊,、天然氣泄漏,、火災(zāi)等，甚至包括由于感官減退導(dǎo)致的潛在營(yíng)養(yǎng)問(wèn)題,。（生物谷Bioon.com）
doi: 10.1371/journal.pone.0045544
PMC:
PMID:
Profound olfactory dysfunction in myasthenia gravis
Leon-Sarmiento FE, Bayona EA, Bayona-Prieto J, Osman A, Doty RL.
In this study we demonstrate that myasthenia gravis, an autoimmune disease strongly identified with deficient acetylcholine receptor transmission at the post-synaptic neuromuscular junction, is accompanied by a profound loss of olfactory function. Twenty-seven MG patients, 27 matched healthy controls, and 11 patients with polymiositis, a disease with peripheral neuromuscular symptoms analogous to myasthenia gravis with no known central nervous system involvement, were tested. All were administered the University of Pennsylvania Smell Identification Test (UPSIT) and the Picture Identification Test (PIT), a test analogous in content and form to the UPSIT designed to control for non-olfactory cognitive confounds. The UPSIT scores of the myasthenia gravis patients were markedly lower than those of the age- and sex-matched normal controls [respective means (SDs)?=?20.15 (6.40) & 35.67 (4.95); p<0.0001], as well as those of the polymiositis patients who scored slightly below the normal range [33.30 (1.42); p<0.0001]. The latter finding, along with direct monitoring of the inhalation of the patients during testing, implies that the MG-related olfactory deficit is unlikely due to difficulties sniffing, per se. All PIT scores were within or near the normal range, although subtle deficits were apparent in both the MG and PM patients, conceivably reflecting influences of mild cognitive impairment. No relationships between performance on the UPSIT and thymectomy, time since diagnosis, type of treatment regimen, or the presence or absence of serum anti-nicotinic or muscarinic antibodies were apparent. Our findings suggest that MG influences olfactory function to the same degree as observed in a number of neurodegenerative diseases in which central nervous system cholinergic dysfunction has been documented.
