虚拟现实功能能力评估工具(VRFCAT)可帮助对早期阿尔兹海默病(AD)和轻度认知功能障碍(MCI)发出警告。

        “我们有很多证据都证明VRFCAT对精神分裂症的功能分类是有作用的。我们需要更敏感的工具以对AD和早期MCI进行检测，这些疾病问题要比基于信息提供者的衡量手段获得和备案的信息所示的微妙得多，”本文的主要作者——美国北卡罗来纳州达勒姆NeuroCog试验医学博士Alexandra Atkins称。

        “VRFCAT通过模拟现实的环境可对日常生活中的常规活动进行再现。它是对功能能力进行衡量的一种新型的基于游戏的手段。在临床试验中，使用VRFCAT可提高对中枢神经系统障碍患者进行功能检测的有效性和敏感性，” Atkins在美国临床精神药理学协会(ASCP)2015年年会上称。

        “目前，功能能力的评估很大程度上都依赖于患者配偶报告的各种衡量方法，可是这些方法对临床前MCI或AD的细微功能缺陷缺乏敏感性，”她说。

        “在面对老年患者人群时，那确实是个问题。患者的配偶，通常情况就是提供患者消息的人，可是他或她本身也具有认知困难的可能。此外，在临床试验中，提供信息者是变化着的，他们也在变老，因此得到可靠的报告就比较困难了。这些基于信息提供者的心理测量法并不是你想在临床试验中实现什么样的效果就是什么样的效果，也不是你想让它们显示随时间变化的可靠变化就可以显示的，”她说。

        在验证VRFCAT可帮助对精神分裂症进行功能评估之后，Atkins博士和她的团队把注意力转移到了研究该工具在评估认知功能中的潜在用途。

        “在没有证据证明一种药物对认知功能具有功效时，FDA是不会批准该药的。例如，即使你让认知能力测量提高了两个点(可能具有显著性)，可是FDA也需要知道这个提高对患者具有何种意义。因此在精神分裂症和AD患者中，你需要通过功能性测量和认知能力测量证明患者状况改善或损害减少。这就是VRFCAT会非常有用的原因。它是一种客观的测量方法，能够测量出状况的恶化或改善及其在临床试验中的重要作用，” Atkins博士称。

        本文摘译自以下原文：

        The Virtual Reality Functional Capacity Assessment Tool (VRFCAT) may be useful in sending up an alarm about early Alzheimer's disease (AD) and mild cognitive impairment (MCI).

        "We have a lot of evidence that the VRFCAT is useful for classifying function in schizophrenia, and we need more sensitive tools in preclinical Alzheimer's disease and early mild cognitive impairment, where those deficits are much more subtle than can often be documented and captured by informant-based measures," lead author Alexandra Atkins, PhD, of NeuroCog Trials, Durham, North Carolina, told Medscape Medical News.

        "The VRFCAT is a novel, interactive gaming-based measure of functional capacity that uses a realistic simulated environment to recreate routine activities of daily living. Use of the VRFCAT may improve validity and sensitivity of measurement of function in clinical trials of patients with central nervous system disorders," Dr Atkins said here at the American Society of Clinical Psychopharmacology (ASCP) 2015 Annual Meeting.

        "Currently, evaluation of functional capacity relies heavily on partner-reported measures that lack sensitivity to subtle functional deficits in preclinical MCI or AD," she said.

        "That's really a problem when you have a geriatric population, and you have a spouse who is generally the informant who has potential cognitive difficulties of his or her own. Also, in clinical trials, the informants are changing, they are getting older, so it can be difficult to get reliable reports. The psychometrics of those informant-based measures are not where you want them to be in a clinical trial, where you want to be able to reliably show change over time," she said.

        After validating that the VRFCAT was useful in assessing function in schizophrenia, Dr Atkins and her group turned their attention to studying the tool's potential utility in assessing cognitive function.

        "The FDA won't give approval of a drug for a cognitive indication without some evidence that there is a functional effect as well. For example, if you improve 2 points on a cognitive measure, that might be significant, but the FDA wants to know that that improvement has some meaningfulness for the subject. So both in schizophrenia and Alzheimer's disease, you need to demonstrate improvement, or reduced impairment on a measure of functioning, in addition to a cognitive measure. This is where the VRFCAT can be very useful. It is an objective way of measuring whether there has been a decline or improvement, and its important use would be in clinical trials," Dr Atkins said.

        She and her group examined age-related differences in VRFCAT performance to assess the sensitivity of the tool in measuring functional declines associated with normal aging.

        "We hypothesized that the VRFCAT would show a difference between the ease and speed with which the young and old could do a particular task," Dr Atkins said.

        The study included 44 healthy young adults aged 18 to 30 years (24 male, 20 female) and 39 healthy older adults aged 55 to 70 years (14 male, 25 female) who completed the VRFCAT at two visits. None of the study participants had cognitive deficits.

        The VRFCAT asked both groups to complete tasks involving instrumental activities of daily living while seated at computers.

        The VRFCAT followed a narrative. The participants began in a kitchen and were told that they were having some friends over for dinner and were given a recipe to prepare. They then had to search the cabinets and refrigerator for recipe ingredients and prepare a grocery list.

        In the next portion of the task, the participants were at a bus stop and had to select the appropriate bus and then pay the fare to get to the grocery store. Once at the grocery story, participants had to select items from the grocery list and pay for them. Finally, they had to catch and pay for the appropriate bus home.

        The study results showed strong age-related differences in performance on each VRFCAT outcome measure, including the total time it took participants to complete the tasks, the total errors they made, and the total forced progressions after time had run out in completing a task (P < .001 for all).

        "Older people were slower than younger people, and this is actually normal. There is a general slowing in aging, and all the variables we looked at were significantly slower for the older adults," Dr Atkins said.

        The older participants took an average of 3 minutes longer to complete the VRFCAT and made an average of two more errors during the test. The older participants made significantly more errors in the following tasks:

        Searching the kitchen for ingredients while referring to the recipe

        Shopping for groceries and selecting items using the shopping list

        Paying for the groceries

        Paying for the bus

        Although the older adults were significantly slower on all VRFCAT tasks, differences were most pronounced in tasks involving executive processing and manipulation in working memory, such as searching the kitchen for ingredients while referring to the recipe, shopping for groceries, and selecting items using the shopping list.

        "These are tasks that involve a lot of working memory or executive functioning. We know that these decline in the normal aging process, and the consequence of this for function is subtle," Dr Atkins noted.

        "When you are trying to identify preclinical Alzheimer's disease, tracking the extent of this decline could be useful. If you have something like the VRFCAT, it can tell what the patient's baseline is, and then you can look at change over time, so you have some measure of how well the patient is able to function at various time points. A person at risk for Alzheimer's disease might show a steeper decline in function on the VRFCAT after, say, 6 months than another older person who is aging normally," she said.

        Objective Measures Needed

        "Clinically relevant and patient-centered functional measures are needed to measure responses to interventions for memory-related disorders," said Bradley N. Gaynes, MD, MPH, professor of psychiatry at the University of North Carolina School of Medicine, in Chapel Hill, when asked by Medscape Medical News to comment on this study.

        Dr Bradley Gaynes

        "Key challenges to this development are finding sensitive assessments that patients with possible memory difficulties can complete. A virtual functional assessment that can be used by those with memory deficits, especially the elderly, might help meet this need," Dr Gaynes, who was not part of the study, said.

        "This study is a preliminary but very promising method to do such assessments. It's just a first step; no individuals with cognitive disorders were assessed, but developing and testing the feasibility of this tool in normal elderly patients is an important movement towards making such assessments a reality. I'm excited to see further study of this tool," he said.

        The study was funded by NeuroCog. Dr Atkins is an employee of NeuroCog. Dr Gaynes reports no relevant financial relationships.

        American Society of Clinical Psychopharmacology (ASCP) 2015 Annual Meeting. Abstract 3000304. Presented June 23, 2015.