Ms. Gaines analyzed results collected through the Penn State Child Cohort to study long-term effects of slow-wave sleep loss from childhood to adolescence. The cohort included 700 children from the general central Pennsylvania population between ages 5 and 12. Eight years later, 421 participants were followed up during adolescence, and 53.9% were male.
Participants stayed overnight at the beginning of the study and at the follow-up and had their sleep monitored for nine hours. At the follow-up appointment, participants’ body fat and insulin resistance were measured, and participants also underwent neurocognitive testing.
Gaines found that in boys, a greater loss of slow-wave sleep between childhood and adolescence was significantly associated with insulin resistance, and this loss was marginally associated with increased belly fat and impaired attention. Ms. Gaines did not find any associations between slow-wave sleep and insulin resistance, physical health, or brain function in girls, however.
Importantly, the participants’ sleep duration did not decline significantly with age, suggesting that the effects observed were due to a loss of this deeper stage of sleep, according to the researcher.
“More longitudinal studies are needed to replicate these findings, especially in other age groups,” said Ms. Gaines. “Studies looking at the effects of experimentally enhanced slow-wave sleep are also necessary. In the meantime, we can use these findings as a springboard for future work on the sleep–health connection. The best thing we can do for ourselves today is keep a consistent sleep schedule, so as not to deprive ourselves of any more slow-wave sleep than we’re already naturally losing with age.”
Apraxia Can Progress to Neurodegenerative Disease
Primary progressive apraxia of speech, a disorder related to degenerative neurologic disease, often goes unrecognized, according to Keith Josephs, MD, a neurologist, and Joseph R. Duffy, PhD, a speech pathologist, both at Mayo Clinic in Rochester, Minnesota.
Because patients and many medical professionals don’t recognize apraxia of speech, treatment typically is sought in later stages of the disease, said Dr. Josephs. As apraxia progresses, it frequently is misdiagnosed as Alzheimer’s disease or amyotrophic lateral sclerosis. One patient received vocal cord injections of Botox by a physician who thought that the problem was muscle spasms of the larynx.
Apraxia of speech also has been diagnosed as mental illness. “Because it first presents as ‘just’ a speech problem, some people are told, ‘This is in your head.’ We’ve seen that. It’s very sad,” said Dr. Josephs.
When it is caused by a stroke, apraxia of speech typically does not worsen and may get better over time. But apraxia of speech often is ignored as a distinct entity that can evolve into a neurologic disorder, causing difficulty with eye movement, using the limbs, walking, and falling that worsens as time passes.
“I don’t want the take-home message to be that this condition is benign,” said Dr. Josephs. “It is a devastating disease, in some sense worse than Alzheimer’s disease, which typically spares balance and walking until very late in the disease course. It may start with the person simply not being able to pronounce a few words. Six years after that, they are in a diaper, can’t speak, can’t walk, and are drooling.”
The benefit to getting an early and correct diagnosis is that people can receive appropriate therapy. “It would be good if people recognized that changes in speech can be the first signs of neurologic disease,” said Dr. Duffy. “An important part of treatment is providing information about the condition.”
While speech therapy doesn’t reverse or halt the progression of apraxia, it can develop compensations for producing better sounds. People with apraxia of speech also can use computers or texting for alternate means of communicating.
The value and complexities of speech often are underappreciated. “Speech is what connects us to the world,” said Dr. Duffy. Speech is a complex brain–body achievement, the researchers noted. It first requires selection of appropriate words and organizing them into a coherent message. This message activates 100 muscles between the lungs and lips to produce at least 14 distinct sounds per second that a listener can comprehend. A problem with speech programming, directing the muscles and structures that move, is apraxia.
People with apraxia of speech or their loved ones may notice a slow speech rate; inconsistent mistakes, such as saying a word or sound correctly sometimes and not others; impaired rhythm of speech; groping of the mouth to make sounds; and better automatic speech, such as greetings, compared with purposeful speech.
Apraxia of speech differs from aphasia, a language disorder that interferes with a patient’s ability to understand or use words. Patients, however, can have apraxia of speech and aphasia.