In infants, pain from vaccinations shows up in brain activity

January 26, 2015, Wolters Kluwer Health

Infants show distinct, consistent patterns of brain activity in response to painful vaccinations, reports a study in the February issue of Pain, the official publication of the International Association for the Study of Pain.

"We have shown that inoculation evokes, from the time of the first needle contact, a clearly defined EEG response in infants up to at least one year of age," write Dr Madeleine Verriotis and colleagues of University College London. They believe this "brain-led approach" to assessing procedure-related pain in infants may help in developing improved vaccination techniques and pain-relieving treatments.

Brain Activity in Response to Shots in Infants...

The researchers performed elecroencephalography (EEG) in 15 healthy babies receiving routine vaccinations. A noninvasive and painless procedure, EEG is done to measure electrical activity in the brain, using electrodes placed in specific locations on the scalp. Twelve infants were tested during vaccinations at age one to two months, and five at age 12 months.

Dr Verriotis and colleagues compared the EEG findings with behavioral pain responses: facial expression, crying, and movements. Such are the standard method for assessing pain in preverbal infants. The researchers filmed the procedures to identify the precise timing of EEG responses to vaccination pain.

The EEG recordings showed two clear waveforms, or "spikes," which appeared within milliseconds after the first contact of the needle with the infant's skin. Although the waveforms appeared in both age groups, they were significantly larger in one- to two-month-old infants than in one-year-olds.

In three infants studied at both ages, the EEG responses—particularly for the first waveform—appeared clearer and larger at age 12 months. The EEG patterns were also more reproducible in older infants. The researchers suggest that these age-related differences might reflect developmental changes in the brain during the first year of life: an increased number of neurons (nerve cells), a larger proportion of neurons being activated, or better synchronization of firing activity.

...But No Relation between EEG and Behavioral Pain Responses

Of course, infants of both ages showed strong and immediate behavioral responses to the vaccinations. However, there was no direct association between differences in the EEG waveforms and differences in the behavioral pain responses.

This may have at least partly reflected the fact that behavioral pain responses were close to maximal (8 on a 10-point scale) in most infants. Dr Verriotis and coauthors write, "Cortical EEG activity...shows that the noxious stimulus is being processed in the brain, with some individual variability, but is not necessarily a direct read-out of the amount of pain perceived."

Vaccinations are the most common cause of procedural pain in children. Although it may seem harmless, pain from frequent vaccinations is a source of anxiety and distress for the child, and a concern to parents as well as healthcare providers. "There is emerging evidence that fear of needles in both parents and children affects medical care," the researchers note. Improved pain management during routine vaccinations is therefore an important goal.

The new study, by showing a "clearly defined EEG response" to shots in up to one year of age "may provide a quantitative measure of cortical pain activity that could be used to investigate the efficacy of pain relieving interventions," Dr Verriotis and colleagues conclude. They add that future studies tracking pain responses over time may help in understanding the long-term development of processing in the infant brain.

Explore further: New method of infant pain assessment

More information: "Cortical activity evoked by inoculation needle prick in infants up to one-year old" journals.lww.com/pain/Fulltext … lation_needle.6.aspx

Related Stories

New method of infant pain assessment

December 21, 2011
Recently, the accuracy of current methods of pain assessment in babies have been called into question. New research from London-area hospitals and the University of Oxford measures brain activity in infants to better understand ...

Research finds pain in infancy alters response to stress, anxiety later in life

October 30, 2013
(Medical Xpress)—Early life pain alters neural circuits in the brain that regulate stress, suggesting pain experienced by infants who often do not receive analgesics while undergoing tests and treatment in neonatal intensive ...

Whites of their eyes: Study finds infants respond to social cues from sclera

October 27, 2014
Humans are the only primates with large, highly visible sclera – the white part of the eye.

Mother's soothing presence makes pain go away—and changes gene activity in infant brain

November 18, 2014
A mother's "TLC" not only can help soothe pain in infants, but it may also impact early brain development by altering gene activity in a part of the brain involved in emotions, according to new study from NYU Langone Medical ...

Recommended for you

Rare in-vivo study shows weak brain nodes have strong influence on memory network

June 20, 2018
Our ability to learn, remember, problem solve, and speak are all cognitive functions related to different parts of our brain. If researchers can identify how those brain parts communicate and exchange information with each ...

A dual-therapy approach to boost motor recovery after a stroke

June 20, 2018
Paralysis of an arm and/or leg is one of the most common effects of a stroke. But thanks to research carried out by scientists at the Defitech Foundation Chair in Brain-Machine Interface and collaborators, stroke victims ...

Scientists unravel DNA code behind rare neurologic disease

June 20, 2018
Scientists conducting one of the largest full DNA analyses of a rare disease have identified a gene mutation associated with a perplexing brain condition that blinds and paralyzes patients.

Powerful new approach helps understand molecular alterations in neurological disease

June 20, 2018
Neurological diseases are typically associated with a multitude of molecular changes. But out of these thousands of changes in gene expression, which ones are actually driving the disease? To answer this question, a team ...

New technique fine-tunes treatment for severe epilepsy cases

June 20, 2018
One of three epilepsy patients experience no relief from drugs and are candidates for surgery. An advance by researchers at Yale and the Cleveland Clinic will enable surgeons to more precisely target areas of the brain causing ...

Absence epilepsy—when the brain is like 'an orchestra without a conductor'

June 20, 2018
At first, the teacher described her six-year-old student as absentminded, a daydreamer. The boy was having difficulty paying attention in class. As the teacher watched the boy closely, she realized that he was not daydreaming. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.