本帖最後由 lsc0019 於 2009-9-15 23:27 編輯
作者：Pauline Anderson
出處：WebMD醫學新聞
August 27, 2009 —一篇族群基礎研究認為，原發性顫抖症(essential tremor，ET)的年長病患，發生失智症的比率是那些沒有ET者的將近兩倍。此外，研究也顯示，ET與發生失智風險增加大約60%有關。
第一作者、紐約市哥倫比亞大學的Elan D. Louis醫師向Medscape Psychiatry表示，這些研究結果指出，ET病患的失智症發生率遠超過在老年病患預期會發生的比率。
Louis醫師表示，研究發現也認為，醫師應和他們的ET病患討論認知議題以及可能的治療選項。
Louis醫師表示，這些結果有助於確認這些病患是否實際上有認知問題，而不只是一般老化。醫師應瞭解，這的確會發生，他們應提供治療給病患。
本研究發表於8月25日的神經學(Neurology)期刊。
【一般狀況】
ET在80歲以上病患常見，影響約10%至20%的此類人口。根據該研究，ET病患曾有輕微認知缺損的報告。
此外，西班牙的一篇單一族群基礎研究，也報告過ET和失智症之間的關係。不過，研究者指出，還沒有其他研究確認過。
為了確認原本的ET是否與失智症的盛行率和發生率有關，研究者針對納入「Washington/Hamilton Heights and Inwood Aging Project」這項計畫的2,285名65歲以上白人、黑人、西班牙病患進行研究，這些研究對象的平均年紀是77.6歲。
評估這些研究對象一開始的神經症狀和憂鬱症狀，18個月後再評估一次。為了確認有無出現ET，研究者使用多種手寫測試以及由一名神經科醫師進行獨立分析。
研究者不知道顫抖狀況，使用醫療病歷、檢驗、神經生理檢查、神經檢查等判定失智診斷。排除巴金森氏症(Parkinson's disease，PD)病患。
【ET與MCI之間沒有關聯】
2,285名研究對象中，124名(5.4%)有ET。229名(10.0%)病患有失智，452名(19.8%)病患有輕微認知不良(mild cognitive impairment，MCI)。
124名ET病患中，31名(25.0%)病患有失智，2161名控制組病患中，198名(9.2%)病患有失智。校正模式中，ET與失智症有關，勝算比為3.31 (95%信心區間[CI]) 2.15 – 5.09；P < .01)。校正年紀、教育、種族之後，勝算比為1.84 (95% CI，1.13 – 2.98；P = .01)。
排除MCI案例之後，校正勝算比為1.84，排除憂鬱病患之後，校正勝算比為2.10。校正藥物與APOE-e4基因狀態之後，此關聯依舊成立。
作者們也進行了一個前瞻性分析。排除原本就有失智的病患後，剩下93名ET病患以及1,963名控制組，校正分析發現，在平均3.8年的追蹤之後，ET病患有失智的風險增加超過1.5倍。
Louis醫師表示，一般認為PD病患有一種神經退化狀況，而且會讓你有另一個狀況，我認為ET也是一樣。
不過，ET與發生MCI的風險增加無關，這發現似乎相當令人驚訝，因為許多MCI病患最後有發生失智。根據作者，還不清楚何以研究並未發現ET與MCI的關係。
【追上PD的研究】
此研究反映出之前有關PD與失智的研究。Louis醫師表示，現在，有關ET的研究就像30或40年前的PD研究，當時病患前來就醫並表示他們有認知問題，而醫師往往是告知「你只是老化」。這對處理這些疾病來說，有點掉以輕心，並未試圖儘可能地處理這些可能是與疾病有關的問題。
他表示，今日，清楚地瞭解到有認知問題且PD與失智有關。不過，與ET的關聯還不清楚。Louis醫師表示，專家不願意提出ET和認知缺損，包括失智之間的關聯。他表示，許多人相信，因為ET和失智是老年人常見的問題，老年人有這兩種狀況並不令人意外。
Louis醫師表示，仍有些神經科醫師和動作異常專家堅信現在已經過時的看法：ET只是動作系統的一種疾病。
【需嚴肅面對這些發現】
明尼蘇達州梅約診所神經科教授David Knopman醫師表示，該研究表現出一個很有趣且須嚴肅面對的新觀察。
不過，他表示，他不知道為何ET病患的失智風險增加。關於這為何會發生，我現在無法正確得知。目前沒有明確的生物學解釋，但並不表示這不是真的。
他指出，該研究並未包括也有ET的年輕病患。他們並未探討中年時的ET有無預測價值，我擔心這對研究可能會造成影響。
Louis醫師宣告他接受國家健康研究中心與巴金森氏症基金會的研究支持。Nicole Schupf 醫師擔任Elan Pharmaceuticals藥廠的文獻回顧顧問，也接受國家健康研究中心和阿滋海默氏症協會的研究支持。Sujata P. Thawani醫師宣告沒有相關財務關係。
Essential Tremor May Raise Dementia Risk
By Pauline Anderson
Medscape Medical News
August 27, 2009 — Older patients with essential tremor (ET) are almost twice as likely to have dementia compared with their counterparts without ET, a population-based study suggests. In addition, the research also shows that ET is associated with about a 60% increased risk of developing dementia.
These results indicate that the prevalence of dementia among patients with ET is "above and beyond" what is expected by chance in aging patients, lead author Elan D. Louis, MD, from Columbia University, New York City, told Medscape Psychiatry.
The study findings also suggest that physicians should discuss cognitive issues and possibly treatment options with their ET patients, said Dr. Louis.
"These results are helpful in validating that these patients are indeed having a cognitive problem — that it's not just usual aging. Doctors should be aware that this can occur and that it can open the door for treating patients," said Dr. Louis.
The study is published in the August 25 issue of Neurology.
Common Condition
ET is common among those older than 80 years, affecting between 10% and 20% of this population. According to the study, mild cognitive deficits have been reported in patients with ET.
In addition, an association between ET and dementia has been reported in a single population-based study in Spain. However, the researchers note, this has not been confirmed elsewhere.
To determine whether baseline ET is linked with prevalent and incident dementia, the investigators studied 2285 white, black, and Hispanic patients aged 65 years and older enrolled in the Washington/Hamilton Heights and Inwood Aging Project. The mean age of the participants in this sample was 77.6 years.
Participants were assessed for depressive and neurological symptoms at baseline, and again every 18 months. To determine the presence of ET, the researchers used various handwriting tests and independent analyses by a neurologist.
To arrive at a diagnosis of dementia, investigators, who were blinded to tremor ratings, used medical charts, laboratory studies, neuropsychological tests, and neurological examinations. Patients with Parkinson's disease (PD) were excluded.
No Link Between ET and MCI
Of the 2285 study subjects, 124 (5.4%) had ET. There were 229 (10.0%) patients with dementia and 452 (19.8%) with mild cognitive impairment (MCI).
Of the 124 patients with ET, 31 (25.0%) had dementia compared with 198 (9.2%) of 2161 control patients. In an unadjusted model, ET was associated with dementia with an odds ratio of 3.31 (95% confidence interval [CI], 2.15 – 5.09; P < .01). After adjusting for age, education, and ethnicity, the odds ratio was 1.84 (95% CI, 1.13 – 2.98; P = .01).
After excluding cases of MCI, the adjusted odds ratio was 1.84, and after excluding patients with depression, the adjusted odds ratio was 2.10. The association also held up after adjustment for medications and APOE-e4 gene status.
The authors also performed a prospective analysis. After excluding patients with baseline dementia, leaving 93 patients with ET and 1963 control patients, adjusted analyses revealed that ET was associated with more than a 1.5-fold increased risk for dementia after a mean follow-up of 3.8 years.
"It is thought that in PD, having one neurodegenerative condition predisposes you to having a second one, and I think it's the same in ET," said Dr. Louis.
However, ET was not associated with increased risk of developing MCI, a finding that seems surprising given that many patients with MCI eventually develop dementia. According to the authors, it is unclear why the study did not find an association between ET and MCI.
Catching Up to PD
This study mirrors previous research linking PD with dementia. "Right now, with ET, we are where we were with PD about 30 or 40 years ago, when patients would go to the doctor and say they had problems with cognition and they would be told, 'you're just getting older,' " said Dr. Louis. "That is a somewhat dismissive way to deal with these issues — there's no attempt to deal with these issues as possibly disease-related."
Today, he said, there is a clear recognition that there are cognitive problems and frank dementia in PD. However, this is not yet the case with ET. Specialists are resistant to the notion that there is a link between ET and cognitive deficits, including dementia, said Dr. Louis. Many believe that because both ET and dementia are common in the aging population, it is not surprising that elderly people would have both conditions, he said.
"There are still some neurologists and movement disorder specialists who cling to the now antiquated notion that ET is just a disease of the motor system," said Dr. Louis.
Finding Needs To Be Taken Seriously
David Knopman, MD, professor of neurology, Mayo Clinic, Rochester, Minnesota, said the study represents "a very interesting and novel observation" that "needs to be taken seriously."
However, he said he does not know why there is an increased risk for dementia among ET patients. "There's no reason I know of right at the moment as to why this would occur. There's not an obvious biological explanation which certainly doesn't mean that it's not true."
He noted that the study did not include younger patients who also get ET. "They didn't look at whether ET in midlife has any predictive value, and I'm afraid that's going to get lost in the shuffle here."
Dr. Louis has disclosed that he receives research support from the National Institutes of Health and the Parkinson's Disease Foundation. Dr. Nicole Schupf serves as consultant on literature review for Elan Pharmaceuticals and receives research support from the National Institutes of Health and the Alzheimer's Association. Dr. Sujata P. Thawani has disclosed no relevant financial relationships.
Neurology. 2009;73:621–625. |
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