費城大學的Samir K. Balas醫師在編輯評論中表示，該研究強調的事實是，SCA病患的神經認知不佳可能被忽視了，或者被視為適應不良的行為表現，而未被視為器質性惡化的結果。
Balas醫師指出，對鐮刀型貧血症成人病患而言，標準與綜合的神經心理評估是一個有價值的評估工具。
國家心臟、肺臟與血液研究中心支持本研究，研究作者與Balas醫師皆宣告沒有相關財務關係。
Sickle Cell Anemia Linked to Cognitive Dysfunction
By Caroline Cassels
Medscape Medical News
May 11, 2010 — Sickle cell anemia (SCA) has been linked to impaired cognitive function in adults and appears to have a much greater negative effect on the brain than previously thought, a cross-sectional, multicenter study suggests.
In the first study to examine cognitive functioning in adults with SCA, investigators found the disease was associated with lower than average nonverbal function scores compared with healthy controls.
SCA patients also had lower average scores for measures of processing speed, working memory, global cognitive function, and most measures of executive function. Difficulties with selective attention in SCA patients were illustrated by lower average scores for tests regarding visual scanning and attention.
The researchers suggest that patients with scores in the below average range may translate into challenges in difficulties with employment, financial management, medication adherence, use of community resources, and social functioning.
The study is published in the May 12 issue of the Journal of the American Medical Association.
Chronic Adult Illness
Once considered a childhood illness that was associated with high pediatric mortality, the average life span for patients with SCA now exceeds 50 years. As a result, SCA has become a chronic illness associated with progressive deterioration in quality of life.
"Neurocognitive dysfunction may be the most important and least studied problem affecting this aging population. To our knowledge, controlled studies of neurocognitive function in adult patients have not been reported and routine screening after childhood is not performed," researchers led by Elliott P. Vichinsky, MD, of Children's Hospital Research Center in Oakland, California, write.
The researchers compared neuropsychological function and neuroimaging findings between 149 neurologically asymptomatic adults aged 19 to 55 years of African descent with SCA recruited from 12 centers in the United States between December 2004 and May 2008 and 48 healthy matched controls from the community.
The study's primary outcome measure was nonverbal function assessed by the Wechsler Adult Intelligence Scale, Third Edition (WAIS-III), Performance IQ (PIQ) Index.
Secondary exploratory outcomes included performance on neurocognitive tests of executive function, memory, attention, and language. In addition, all participants underwent magnetic resonance imaging (MRI) measurement of total intracranial and hippocampal volume, cortical gray and white matter, and lacunae.
Imaging Findings Do Not Explain Performance Differences
After adjusting for age, sex, and education level, the investigators found SCA patients had statistically significant lower average nonverbal function scores than controls. The WAIS-III PIQ score was more than 1 SD below the normative average for 33% of patients and 15% of controls, compared with an expected 16% from the national norms.
SCA patients also had lower average scores on all secondary outcomes. According to investigators MRI findings did not explain performance differences because no differences in total gray matter or hippocampal volume were observed.
"Adult patients with SCA who are neurologically asymptomatic are still at risk for neurocognitive performance deficits because their anemia may be inducing neurocognitive impairment secondary to cerebral hypoxemia undetectable by standard neuroimaging studies," they write.
However, they add, several steps can be taken to try and mitigate the impact of SCA on cognition. "First, early identification of patients with difficulties on specific measures of neurocognitive function may allow these patients to enroll in, and benefit from, cognitive rehabilitation programs.
"Additionally, longitudinal studies are necessary to understand and evaluate disease progression. These studies can be linked to biological components to improve understanding of neurocognitive function in SCA," the study authors write.
They conclude that intervention studies testing treatments such as transfusion therapy, neuroprotective agents, hydroxyurea, and oxygenation and their ability to improve cognition in this patient population are needed.
In an accompanying editorial, Samir K. Balas, MD, Thomas Jefferson University in Philadelphia, Pennsylvania, says the study highlights the fact that "neurocognitive deficits may be overlooked in adult patients with SCA or discounted as a manifestation of maladaptive behavior rather than recognized as the result of an organic process."
Dr. Balas adds that standardized and comprehensive neuropsychological assessment may be a valuable tool in managing adult patients with sickle cell disease.
The study was supported by the National Heart, Lung, and Blood Institute. The study authors and Dr. Balas have disclosed no relevant financial relationships.
