男女羞羞视频在线观看,国产精品黄色免费,麻豆91在线视频,美女被羞羞免费软件下载,国产的一级片,亚洲熟色妇,天天操夜夜摸,一区二区三区在线电影

Imagined smells can precede migraines

Updated: 2011-10-17 10:46

(Agencies)

  Comments() Print Mail Large Medium  Small 分享按鈕 0

Hallucinated scents such as a burning or rotten smell, or even the scent of foie gras, can be a part of the "aura" that some people perceive before a migraine attack, although it is rare, according to a US study.

About 30 percent of people with recurrent migraines have sensory disturbances shortly before their headache hits, known as aura, but these are usually visual, such as flashes of light or blind spots. Tingling sensations or numbness, or difficulty speaking or understanding language, may also appear.

But the study, conducted by Matthew Robbins and colleagues at the Montefiore Headache Center in New York, found that a small number of people described smelling scents in conjunction with their headaches.

"It's uncommon, but distinctive," said Robbins, noting that disturbances in the sense of smell, known as olfactory hallucinations, have not been covered in a systematic review of medical literature before.

Researchers reviewed 25 reported cases of patients with headaches, migraines in most cases, and olfactory hallucinations. They also examined records from more than 2,100 patients seen over 30 months. Fourteen people, or just under 0.7 percent, had described smelling scents ahead of their headaches.

"The most common was of the burning or smoke variety," Robbins said.

Some sufferers described a general burning smell. Others said they smelled cigar smoke, wood smoke or burnt popcorn.

"Decomposition" odors, such as garbage or sewage, were the next most common smell reported. A few people described pleasant odours, including the scent of oranges, coffee or, in one case, foie gras.

About 11 percent of the world's population suffers from migraines, so even though olfactory hallucinations are an unusual part of aura, there could still be a fairly large number of people who experience them, Robbins said.

It's not clear why the hallucinated odors are most often unpleasant, or why they are only rarely part of migraine aura.

But aura symptoms are thought to involve a phenomenon called "cortical spreading depression," where a wave of increased electrical activity in nerve cells of the brain is followed by a wave of depressed activity, Robbins said.

That same phenomenon might underlie olfactory hallucinations -- and because the brain's smell centres occupy much less space than its sight centres, that could, in theory, explain why phantom scents are so much less common, he added.

It is also possible that some people with migraines and olfactory hallucinations do not recognise the phenomenon, he added. People know something is wrong when they see zigzag lines, but it is easy to assume a small is actually coming from somewhere.

Since some disorders, such as Parkinson's disease, can cause a person to smell scents that are not present, any such hallucinations without an accompanying headache should be checked out, he warned.

主站蜘蛛池模板: 衡水市| 汶上县| 崇州市| 博兴县| 垣曲县| 彭水| 娄烦县| 淳化县| 仙桃市| 泰宁县| 任丘市| 宣汉县| 卫辉市| 紫云| 恩平市| 策勒县| 景谷| 武定县| 朝阳区| 盐池县| 安仁县| 嘉鱼县| 张家界市| 赤壁市| 东阿县| 延长县| 响水县| 闽清县| 化州市| 申扎县| 黔南| 棋牌| 环江| 泸水县| 汉川市| 湖北省| 克东县| 汤原县| 额敏县| 蒙阴县| 多伦县| 温宿县| 巴彦淖尔市| 临沂市| 丹寨县| 莱芜市| 忻城县| 宁明县| 水城县| 巨鹿县| 新绛县| 奈曼旗| 陆河县| 阿图什市| 镇坪县| 卓尼县| 建德市| 新营市| 东港市| 开远市| 蒙城县| 博乐市| 商都县| 大余县| 乐安县| 泸定县| 宜丰县| 大悟县| 长治市| 贞丰县| 武平县| 宁晋县| 清远市| 南岸区| 万年县| 刚察县| 如皋市| 仁布县| 客服| 黎平县| 乳源| 昭通市|