Computerized cognitive training (CCT) for patients with mild cognitive impairment (MCI) appears to have a beneficial effect on global cognition, memory, and attention and improves psychosocial functioning, including depressive symptoms, new research shows.
However, the review also showed that CCT is of limited benefit for dementia patients and has no impact on executive function or processing speed in patients with MCI.
These cognitive areas do not improve because individual home-based cognitive training sessions typically do not target them, study author Amit Lampit, PhD, dementia research fellow, Brain and Mind Center, University of Sydney, New South Wales, Australia, told Medscape Medical News.
He added that patients need group sessions with a trainer to receive the maximum benefit.
"The key message is that cognitive training, if administered properly in a group format at the right dose and targeting all the domains that we want to improve, can have a meaningful effect, potentially even prevent dementia, although we don't have data on that," he said.
For the study, investigators searched Medline, Embase, PsychINFO, CINAHL and CENTRAL databases and scanned reference lists and previous reviews for randomized controlled trials that examined the effects of CCT on one or more cognitive or behavioral outcomes in older adults with MCI or dementia.
The cognitive interventions had to include at least 4 hours of drill and practice, with a clear cognitive rationale, as well as video games or virtual reality. Studies combining CCT with other interventions were eligible for inclusion if the control group received the same intervention.
Types of controls included passive controls, such as being placed on a wait list; active controls, such as being given sham CCT; and pencil-and-paper cognitive training.
For MCI, the review included 17 studies with 686 participants. The mean age of the participants ranged from 67 to 81 years, and 51.88% were women. For dementia, the review included 12 studies with 389 participants. The mean age was 66 to 81 years, and 63.5% were women.
Most studies involved supervised training, although some employed home-based training or a combination. Most studies (70%) used an active control condition.
The meta-analysis of outcomes in MCI showed that the overall effect size was moderate and statistically significant (Hedges' g = 0.35; 95% confidence interval [CI], 0.20 - 0.51, P < .001).
This effect size was larger than those previously reported for healthy older adults and for patients with Parkinson's disease, the author note.
Participants in CCT groups improved significantly during the intervention period, whereas patients receiving control interventions did not show any cognitive change.
The global cognition effect size for MCI was moderate and statistically significant (g = 0.38; 95% CI, 0.14 - 0.62; P = .002). Again, the pooled effect size across CCT groups was significant compared with control groups, in which no change occurred.
The verbal learning effect size for patients with MCI was also moderate and statistically significant (g = 0.39; 95% CI, 0.14 - 0.63; P = .002), as were verbal memory (g = 0.42; 95% CI, 0.21 - 0.63, P < .001), nonverbal learning (g = 0.50; 95% CI, 0.25 - 0.76; P< .001), working memory (g = 0.74; 95% CI, 0.32 - 1.15; P < .001), and attention (g = 0.44; 95% CI, 0.20 - 0.68; P < .001).
The intervention also improved psychosocial functioning (depression, quality of life, and neuropsychiatric symptoms) in MCI patients (g = 0.52, 95% CI, 0.01 - 1.03; P = .045). The authors note that depression is associated with MCI and conversion to dementia.
No Placebo Effect
The effects across active-controlled and passive-controlled trials were comparable.
"People in control groups, regardless of whether it was an active or passive control, did not change at all, so we did not see a placebo effect," said Dr Lampit.
The moderate effect sizes on most memory and learning domains are "encouraging," as amnestic symptoms are the most common presentation of Alzheimer's disease, and amnestic MCI patients are at higher risk for dementia conversion, the investigators note.
Cognitive training did not have a statistically significant effect on executive function, processing speed, nonverbal memory, visuospatial skills, language, or instrumental activities of daily living in MCI patients.
The lack of effect on executive function, a key predictor of functional decline, across studies likely was a result of the fact that "there was not enough emphasis on executive function within the individual training programs," according to Dr Lampit.
More surprising, say the authors, was the lack of effect on processing speed, because this domain was among the most responsive in a 2014 meta-analysis published in PLOS Medicine that included almost 5000 people, and CCT exercises are typically timed.
However, Dr Lampit noted that "the fact that your memory exercises are timed does not necessarily generalize to improvements in processing speed across the board. Your gains are usually very closely linked to your training exercises, so if you target executive function, you will see improvements in executive function; and if you target speed, you will see improvement in speed."
The meta-analysis in PLOS Medicine did find effects on processing speed, but the gains were limited to those studies that targeted speed. That meta-analysis also found that cognitive training was only effective when done in a supervised group format in which patients underwent up to three training sessions a week.
The study also showed that in patients with dementia, clinically meaningful effect sizes were found for overall cognition and visuospatial skills. However, these were driven by three trials that used virtual reality and Nintendo Wii. Given how engaging these games are visuospatially, that finding was not surprising, said Dr Lampit.
"It is conceivable that these methods are more stimulating and personally engaging than traditional CCT, an idea that merits further research," the authors write.
Until then, "we simply don't have enough studies" using virtual reality to recommend such games for clinical practice, "unlike cognitive training in MCI, which I think is ready for clinical and community implementation," said Dr Lampit.
There were insufficient data to determine whether training gains can be maintained over time without further training.
Dr Lampit said he would probably not recommend that patients sign up and pay for commercial brain training sessions because they are not likely to be effective, although the exercises themselves might be very good.
"When people start doing it at home, they will train irregularly or play games they are better at and not do what they need, and they will very likely stop doing it after a while.
"In sharp contrast, if you do the exact same exercises in a group format at a community center or clinic, then you begin to see very clinically meaningful effects," Dr Lampit said.
Such group sessions, which include up to 10 people who meet regularly, are relatively easy and inexpensive to start up and are safe, he said.
"Most of the work is individual, but there is a person there who makes sure that participants do the exercises that fit them, not only what they like to do, make sure that they train enough, make sure that their motivation is high even after 2 or 3 months doing pretty much the same thing, and make sure they reflect on how these exercises relate to their everday life."
High Risk for Bias
Commenting on the findings for Medscape Medical News, David Knopman, MD, professor of neurology, Mayo Clinic, Rochester, Minnesota, who is an expert in MCI and dementia, said it was interesting that 15 of the 17 studies of MCI individually failed to achieve statistically significant results (the 95% CI of effect included zero) and that 12 of the 17 studies were classified has having a high risk for bias.
"Many of the studies had other methodological flaws. One of the major limitations of meta-analyses is that they are only as good as the weakest of their included studies, and I would say that this meta-analysis has some problems," said Dr Knopman.
On the other hand, he added, the heterogeneity of the interventions "acted against seeing a benefit," so there is "some suggestion" that the results might be generalizable to a variety of CCTs.
The "fundamental" problem is that although the authors were able to show some benefits in cognition, they failed to show that it has an impact on daily life, said Dr Knopman.
"Unfortunately, the authors buried the figure showing psychosocial function in MCI in the supplementary materials, where the confidence interval of the meta-analysis appears to include zero, so no benefit.
"The main concern is that the intervention is able to achieve beneficial effects on laboratory-based cognitive measures, but those benefits don't translate to daily life."
Dr Lampit and Dr Knopman have disclosed no relevant financial relationships.
Am J Psychiatry. Published online November 14, 2016. Abstract
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Cite this: Brain Gain: Computerized Training May Boost Cognition in MCI - Medscape - Nov 17, 2016.