Aerobic Exercise May Provide 'Small' Improvement in Vascular Cognitive Impairment

Deborah Brauser

October 20, 2016

In addition to improving cardiovascular capacity, a progressive aerobic exercise training program may give a small boost to cognitive performance in older patients with mild subcortical ischemic vascular cognitive impairment (SIVCI), new research suggests.

The proof-of-concept randomized trial, which included 70 adults with SIVCI, showed that those who went through the three-times-weekly exercise program for 6 months had a modest but significantly greater improvement of 1.7 points on the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) than those randomly assigned to education plus usual care.

Dr Teresa Liu-Ambrose

Lead author Teresa Liu-Ambrose, PhD, associate professor and Canada Research Chair at the University of British Columbia, Vancouver, Canada, noted in a release that while this mirrors previous research assessing medication treatment for this type of patient population, "the difference was less than what is considered to be the minimal clinically important difference of 3 points."

In addition, the between-group differences were no longer significant when measured at the 6-month postintervention follow-up.

However, "there are very few treatment options for those with vascular cognitive impairment," Dr Liu-Ambrose told Medscape Medical News. "From my and our research group's perspectives, exercise still seems like a sensible choice with minimal side effects."

In fact, the study, which was published online October 19 in Neurology, showed significant improvements for the exercise group at intervention completion in the secondary outcomes of 6-Minute Walk Test and diastolic blood pressure.

When approached for comment, Donald Iverson, MD, Humboldt Neurology, Eureka, California, noted to Medscape Medical News. that the 6-Minute Walk Test finding was especially interesting.

Dr Donald Iverson

"The improvement in cognition had a hint of promise but is not likely to be of much functional significance. But the improvement in the 6-minute timed walk was pretty substantial," said Dr Iverson, who is also the editor of the American Academy of Neurology's NeuroPI program.

Common Cause of Dementia

The investigators note that vascular cognitive impairment "is the second most common cause of dementia after Alzheimer disease" and that SIVCI is the most common version.

"SIVCI is defined by the presence of white matter lesions…and lacunar infarcts, and has the clinical consequence of increased dementia risk."

They add that "no clinical trial [before] utilized aerobic exercise to augment cognitive function in individuals with mild SIVCI."

Preliminary results of this study were first presented at the Alzheimer's Association International Conference last year; full details are provided in the current journal article.

The researchers recruited 70 participants (51% women; mean age, 74 years) at several centers in Vancouver between December 2009 and April 2014. Half of the patients were randomly assigned to the exercise program and the other half to usual care plus education on vascular cognitive impairment and on nutrition (control group).

Each of the 1-hour exercise sessions included an outdoor walk that progressed in intensity and lasted for 40 minutes, with a 10-minute warm-up prior and a 10-minute cool-down afterward. The control group received no information at all about physical activity.

The three prespecified primary outcomes were improvements from baseline on the following measures:

  • the ADAS-Cog for general cognitive function;

  • the Executive Interview (EXIT-25) for executive function; and

  • the Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL).

While improvement on the ADAS-Cog was significantly greater in the walking group than in the control group at the end of the intervention, there were no significant differences between the groups on the EXIT-25 or ADCS-ADL at this time point. And none of these outcomes were significant at the 6-month follow-up.

Table. Adjusted Point Differences for Exercise vs Control Groups

Primary Outcome Measure After Intervention (95% CI) P Value 6-Month Follow-up (95% CI) P Value
ADAS-Cog –1.71 (–3.15 to –0.26) .02 –0.63 (–2.34 to 1.07) .46
EXIT-25 1.45 (–0.55 to 3.45) .15 0.22 (–1.87 to 2.32) .83
ADCS-ADL 1.25 (–0.63 to 3.13) .19 1.34 (–0.68 to 3.37) .19

CI = confidence interval.

 

As for secondary outcomes, the group that underwent the aerobic exercise program had a significantly greater improvement on the 6-Minute Walk Test than did the usual care group (difference in distance walked, 30.35 m; 95% CI, 5.82 - 54.86 m; P = .02).

They also had a greater reduction in resting diastolic blood pressure (difference, –6.89 mm Hg; 95% CI, –12.52 to –1.26 mm Hg; P = .02).

However, there were no between-group differences in systolic blood pressure or on the executive function-measuring Stroop test, Trail-Making test, or Verbal Digit Span test. And, as with the primary outcomes, none of the secondary outcomes had any significant between-group differences at the postintervention follow-up.

The only adverse events reported were nonsyncopal falls, which occurred twice in the exercise group and once in the control group.

Overall, "this study provides Class II evidence that for adults with mild SIVCI, an aerobic exercise program for 6 months results in a small, significant improvement in ADAS-Cog performance," summarize the investigators.

"I would love to see more clinical recommendations and support for exercise in individuals who receive a diagnosis of some sort of cognitive impairment/dementia," said Dr Liu-Ambrose.

"It's a stressful time for individuals when they first start noticing symptoms and when they receive a formal diagnosis. And exercise is something that provides many benefits," she added. "So why wouldn't you recommend it?"

Proof of Concept Achieved

In an accompanying editorial, Alexandra Foubert-Samier, MD, PhD, Institut des Maladies Neurodegeneratives-Clinique at Bordeaux University Hospital, France, and Leon Flicker, PhD, Western Australian Center for Health and Aging at the University of Western Australia, Perth, note that proof of concept was achieved in this study — and that further research is warranted.

"The strengths of this study are not only its randomized design, but also that the study met its predefined feasibility criteria with a recruitment rate of 17%, a withdrawal rate of less than 15%, and an average exercise adherence of 68%," write the editorialists.

They add that although the exercise program not improving executive function was "surprising," this could be because physical activity needs to occur for a longer period to show this type of benefit.

Dr Iverson pointed out to Medscape Medical News that because the study patients had vascular dementia, "whether this is going to be of any benefit in Alzheimer's dementia is another story."

He noted that early studies have reported that exercise can increase hippocampal volume in patients with Alzheimer's disease. Although the results didn't convincingly link exercise to improved cognition, they were "objective and encouraging."

As for the current study, although it was small, its simple intervention "makes common sense and is likely to have other benefits," added Dr Iverson. "It's certainly worth pursuing further, especially given the lack of other interventions that we have for this population at this time."

The study was funded by the Canadian Stroke Network and the Stroke Foundation of Canada. The study authors, editorialists, and Dr Iverson have disclosed no relevant financial relationships.

Neurology. Published online October 19, 2016. Abstract, Editorial

Follow Deborah Brauser on Twitter: @MedscapeDeb. For more Medscape Neurology news, join us on Facebook and Twitter

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....