Hearing Aids May Lessen Cognitive Decline, Memory Loss
A 2018 article by researcher Asri Maharani and colleagues in the Journal of the American Geriatrics Society reports that using a hearing aid was associated with better scores on a test of episodic memory, and that declines in episodic memory slowed after participants began using hearing aids.
The study included 2,040 adults aged 50 years and up. Maharani and colleagues used data from the Health and Retirement Study, which measured participants’ cognitive functioning every two years for 18 years. Participants were asked to recall 10 words both immediately and after some delay.
The authors suggested that improving access to hearing aids earlier in the course of hearing impairment might help to stem the rise of dementia.
Single Dose of Modafinil Improved Memory in People in Remission from Depression
Modafinil is a wake-promoting medication used to treat narcolepsy, but studies have also shown that it can improve cognition in people with schizophrenia or attention deficit hyperactivity disorder. It may also help people with lingering cognitive difficulties after recovering from a depression. A 2016 article in the journal Biological Psychiatry reported that a single 200mg dose of modafinil improved performance on tests of episodic memory and working memory (but not planning or attention).
The study by researcher Barbara Sahakian and colleagues included 60 patients who had recently recovered from a depression. They took some cognitive tests to establish a baseline of their performance. A week later, they were given either a placebo or a single dose of modafinil, and two hours later they completed the cognitive tests again. The modafinil group performed better on the memory-related tasks.
While side effects were limited, two participants who received modafinil had sleep disturbances that night.
Longer-term studies are needed to determine whether modafinil is safe and effective if taken over a longer period of time. Cognitive dysfunction can interfere with daily tasks such as work or school and put people at greater risk of relapse, so effective treatments have the potential to greatly improve quality of life for people in remission from depression.
Low Vitamin D Linked to Cognitive Decline
Low levels of vitamin D levels are common, particularly in older adults and in African Americans and Hispanics. Unfortunately, low vitamin D is associated with decline in two types of cognitive functioning: episodic memory (memories of autobiographical events) and executive function (reasoning, problem-solving, planning, etc.).
A recent study with a particularly diverse group of participants, over half of whom were African American or Hispanic, found that over a period of about 5 years, episodic memory and executive function declined faster in older adults with low levels of vitamin D.
Average vitamin D levels for the entire group of 382 adults were below national standards. Levels of 25-hydroxy vitamin D should be between 20 and 50 nanograms per milliliter of blood. The average fell just below this, at 19.2 ng/mL. Over a quarter of participants had vitamin D deficiency, with levels below 12 ng/mL, and another 35.1% had vitamin D insufficiency, with levels between 12 and 20 ng/mL.
African Americans and Hispanics had lower levels of vitamin D (17.9 ng/mL and 17.2 ng/mL, respectively) than whites (21.7 ng/mL). Average vitamin D levels were lower in participants with dementia compared with those who had mild cognitive impairment or normal cognitive function.
Vitamin D levels can depend on factors such as dairy intake, sun exposure, and exercise. It has not been determined whether taking vitamin D supplements could slow down cognitive decline, but vitamin D supplementation has several benefits. Compared to placebo, supplementation with vitamin D increases response to antidepressants. A high percentage of children with major psychiatric disorders are vitamin D deficient, and it is also estimated that about 40% of adults in the US have a vitamin D deficiency.
The study by researcher Joshua W. Miller and colleagues was published in the journal JAMA Neurology in September.
