ahistoryofpain

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Parental touch reduces pain responses in babies’ brains

The scientists report in the European Journal of Pain that there was more activity in the brains of newborn babies in reaction to the pain when a parent was holding them through clothing, than without clothing.

Joint senior author, Dr Lorenzo Fabrizi (UCL Neuroscience, Physiology & Pharmacology) said: “We have found when a baby is held by their parent, with skin-on-skin contact, the higher-level brain processing in response to pain is somewhat dampened. The baby’s brain is also using a different pathway to process its response to pain.

“While we cannot confirm whether the baby actually feels less pain, our findings reinforce the important role of touch between parents and their newborn babies.”

The study involved 27 infants, 0-96 days old and born premature or at term age, at University College London Hospitals. The researchers were measuring their response to a painful but clinically required heel lance (blood test). Brain activity was recorded with EEG (electroencephalography) electrodes placed on the scalp.

The babies were either held by their mother skin-to-skin (wearing a diaper, against their mother’s chest), or held by their mother with clothing, or else lying in a cot or incubator (most of these babies were swaddled).

The researchers found that the initial brain response to the pain was the same, but as the heel lance elicited a series of four to five waves of brain activity, the later waves of activity were impacted by whether the baby was held skin-to-skin or with clothing.

Joint senior author, Professor Rebecca Pillai Riddell (Department of Psychology, York University, Canada) said: “The slightly delayed response was dampened if there was skin contact with their mother, which suggests that parental touch impacts the brain’s higher level processing. The pain might be the same, but how the baby’s brain processes and reacts to that pain depends on their contact with a parent.

“Our findings support the notion that holding a newborn baby against your skin is important to their development.”

The brains of the babies that remained in the cot or incubator also reacted less strongly to the pain than those held in clothing, but the researchers say that may be because the babies were not disrupted by being picked up before the procedure, or else due to the success of the sensitive, individualised care they were provided.

The babies’ behaviour was not significantly different between the groups, although the skin-to-skin group did exhibit slightly reduced responses in terms of facial expression and heart rate. Other studies have found that skin-to-skin contact with a parent does affect baby behaviour, and may reduce how strongly they react to pain, but those studies did not investigate the brain response.

In the current study, the babies’ brain responses were not only dampened in the skin-to-skin group, but also followed a different neural pathway.

First author, Dr Laura Jones (UCL Neuroscience, Physiology & Pharmacology) said: “Newborn babies’ brains have a high degree of plasticity, particularly those born preterm, and their development is highly dependent on interactions with their parents. Our findings may lend new insights into how babies learn to process threats, as they are particularly sensitive to maternal cues.”

Co-author Dr Judith Meek (University College London Hospitals) said: “Parents and clinicians have known for many years how important skin to skin care is for babies in NICU. Now we have been able to demonstrate that this has a solid neurophysiological basis, which is an exciting discovery.”

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How one pain suppresses the other

The body knows various mechanisms that dampen painful sensations. They can be examined with new methods.

When two painful stimuli act on us at the same time, we perceive the one of them as less painful. This phenomenon is part of the body’s own pain control system. A disfunction of this inhibition is associated with chronic pain disorders. Researchers at Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil, clinic of Ruhr-Universität Bochum (RUB), have developed a method for this. They were able to show that the method works effectively with both painful electrical stimuli and heat pain. Two consecutive studies on this have been published in the journals Brain Sciences and BMC Neuroscience.

The same stimulus hurts differently

The human perception of pain can vary greatly depending on the situation. So it is possible that the same pain stimulus feels more or less painful under different conditions. The body’s own pain control system is responsible for this. Researchers investigate this system with the research method called Conditioned Pain Modulation, or CPM for short. “This records how strongly a painful stimulus inhibits the experience of another painful stimulus that is presented at the same time,” explains Assistant Professor Dr. Oliver Höffken, neurologist at Bergmannsheil.

In the first study, the research team compared an established CPM model with a recently introduced variation. With Conditioned Pain Modulation, two pain stimuli always play a role. The first stimulus, also called the test stimulus, is administered twice: once alone and once in conjunction with the second stimulus, the conditioning stimulus. The test person should assess how painful the test stimulus was on its own and how it felt while the conditioning stimulus was administered.

An objective criterion

In the current work, the team led by Oliver Höffken, Dr. Özüm Özgül and Professor Elena Enax-Krumova compared two different test stimuli: a tried and tested stimulus caused by heat pain and a new one triggered by electrical stimulation of the skin. In both cases the conditioning stimulus was generated by cold water. The electrical stimulation of the skin has a decisive advantage over the previously used heat method: it allows the changes in brain activity triggered by the electrical stimuli of the skin to be measured with the help of EEG recording. This adds an objectively measurable criterion to the subjective pain assessment of the test persons.

Two mechanisms with the same result

In the second study, the researchers used the previously tested CPM model with the electrical stimulation of the skin and compared it to the pain-relieving effect of cognitive distraction. They found that both the CPM method and cognitive distraction can reduce the sensation of pain to a similar degree. However, the two methods showed different results in the measurement of the electrical potentials. “Based on our measurements, we assume that the two pain-relieving effects examined are two different neural mechanisms that just lead to the same effect,” says Höffken.

The researchers carried out their studies on healthy volunteers. However, research into the body’s own pain inhibition system is also relevant in order to better understand various pain disorders. “In patients with chronic pain, the development of postoperative pain and the transition from acute to chronic pain, changed CPM effects have already been found in the past. In our research group, we therefore use the CPM model as an instrument to investigate mechanisms in the processing of painful information”, explains Höffken.

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Modelling the brain during pain processing

The many different sensations our bodies experience are accompanied by deeply complex exchanges of information within the brain, and the feeling of pain is no exception. So far, research has shown how pain intensity can be directly related to specific patterns of oscillation in brain activity, which are altered by the activation and deactivation of the ‘interneurons’ connecting different regions of the brain. However, it remains unclear how the process is affected by ‘inhibitory’ interneurons, which prevent chemical messages from passing between these regions. Through new research published in EPJ B, researchers led by Fernando Montani at Instituto de Física La Plata, Argentina, show that inhibitory interneurons make up 20% of the circuitry in the brain required for pain processing.

The discovery represents a significant advance in researchers’ understanding of how our bodies and brains respond to pain. The underlying circuitry of the pain process involves a specific configuration of interneurons, each of which link specific pairs of regions, or ‘nodes’ within the brain. Crucially, a certain fraction of these neurons will be inhibitory; varying the strengths of the connections they provide. To create a biologically plausible model, Montani and colleagues would first need to consider all possible links between specific pairs of nodes, and determine their relative strengths. Within a structure as complex as the brain, however, it would be virtually impossible to do this by considering each configuration individually.

The researchers overcame this issue using ‘graph theory,’ which studies structures made up of sets of nodes, which influence each other’s behaviours via links of variable strengths. Using a novel statistical approach, they estimated the signals produced by each region of a virtual brain in a given configuration, and how far they diverge from realistic values. From their initial estimates, Montani’s team could then build up a realistic graph by strengthening and weakening the influences of certain links. Their analysis revealed that a configuration where 20% of all interneurons associated with the pain process are inhibitory to information transmission.

[ahistoryofpain]

People with endometriosis : hey you know we’d quite like there to be more research about this very common condition that heavily impacts our lives and is rarely correctly diagnosed

straight cis male scientists : Ok here you go : Women with Severe Endometriosis may be more attractive

People with endometriosis : are you fucking serious

[ahistoryofpain]

Language, cultural identity can affect pain

A new study out of the University of Miami suggests that the language a bilingual person speaks can affect their physical sensations, depending on the cultural association tied to each vernacular.

We take for granted the fact that feelings such as love, happiness, or pain are described with different words and expressions across languages. But are the ways we express these feelings in various languages also tied to differences in the sensations themselves? Would a painful event like a stubbed toe or a bee sting hurt less if a bilingual chose to describe or think about it in Spanish as opposed to English?

These sorts of question were central to the development of a recent study by Morgan Gianola, University of Miami psychology graduate student, along with his advisor, Elizabeth Losin, assistant professor of psychology and director of the Social and Cultural Neuroscience lab at the University of Miami, and Maria Llabre, professor and associate chair of the Department of Psychology at the University of Miami. The study, “Effects of Language Context and Cultural Identity on the Pain Experience of Spanish-English Bilinguals,” is published in the journal Affective Science and will appear as part of the journal’s special issue on “Language and Affect.”

The Social and Cultural Neuroscience Lab uses experimental interactions among research participants to assess how social factors, like the language they speak or the cultural identity they express, can influence pain responses and other clinically relevant behaviors. Gianola joined this lab to research how social environments and cultural learning can be relevant to perceptions as seemingly objective and inherent as pain.

In the study, 80 bilingual Hispanic/Latino participants from the University of Miami and Miami-Dade County communities visited the lab to participate in separate English and Spanish testing sessions. During both sessions, they received a pain-induction procedure, when an experimenter applied painful heat to their inner forearm. The primary difference between the two experimental visits was the language being spoken (English or Spanish), while the painful procedure did not change. Participants provided subjective ratings of their pain, and their physiological responses (i.e. their heart rate and sweatiness of the palms) were also monitored.

Gianola explained that this study was inspired by previous research in the field of “linguistic relativity,” which has shown differences between English and Spanish speakers in cognitive processes like memory for specific events or categorization of objects. These cognitive differences are also seen among bilingual people when they switch between English and Spanish contexts. Gianola hoped to clarify how such psychological differences across languages might also relate to changes in physical and emotional experiences, like pain.

“All of our participants identified as bicultural,” said Gianola. “After each experimental session, we had them fill out surveys about things like how often they use each language [English and Spanish] and how strongly they relate to and identify with both the Hispanic and U.S.-American sides of their cultural identity. The interesting thing we found was, rather than participants always showing higher pain ratings in Spanish, for example, they tended to report more intense pain and show larger physiological responses to pain when they spoke the language of their stronger cultural identity.”

According to the study findings, participants who engaged more with the Hispanic culture showed higher pain when speaking Spanish, while more U.S.-American identified participants reported higher pain in English. People who were fairly balanced in their engagement with U.S.-American and Hispanic culture had pain outcomes that didn’t differ much across languages. The study also suggests that bodily responses to the pain played a larger role in determining pain ratings among more Hispanic oriented bilingual participants.“

This study highlights, first, that Hispanic/Latino communities are not monolithic, and that the factors affecting bilinguals’ psychological and physiological responses to pain can differ across individuals,” said Gianola. “We also see that language can influence such a seemingly basic perception as pain, but that the cultural associations people carry with them may dictate to what extent the language context makes a difference.”

Moving forward, the researchers are developing new experiments to further address the role language plays in influencing cognition and perception among bilingual speakers. As part of a dissertation project, Gianola plans to investigate the brain processes that contribute to the effects found in this most recent study.

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Organism, stimulus and response. Biological basis of behavior. 1963.

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Research Identifies Gender Bias in Estimation of Patients’ Pain

Findings reveal female patients were perceived to be in less pain than males who reported and exhibited the same level of pain intensity.

[ahistoryofpain]

People from relatively low socioeconomic backgrounds are more likely to have their pain sensitivity dismissed by others, according to a new series of psychological experiments.

Even medical professionals don’t seem to take another’s suffering as seriously if they are relatively uneducated or poor – they may even prescribe less medication.

The results could partly explain why patients with higher levels of education, income and social status tend to receive better medical care for a variety of painful conditions in the United States. No doubt, there are also structural issues at play, like a sheer lack of access to medical care, but broader cultural stereotypes appear to also play a role.

Pain is an incredibly difficult symptom to both express and interpret. While the experience of suffering is universal, its measurement is necessarily subjective and is open to a slew of human biases.

Continue Reading.

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WHAT IS PAIN?

An Introduction to the history of pain

The definition of pain:

In July of 2020, the official definition of pain was revised for the first time since 1979 by the International Association for the Study of Pain (IASP).

“An unpleasant sensory and emotional experience associated with. Or resembling that associated with, actual or potential tissue damage.”

This quote is taken directly from Raja et al, (2020), a recent journal detailing the definition of pain.

What does that mean?

From the above quote we can determine that pain is an unpleasant experience. We can also infer that pain can be either physical or psychological, perhaps even a combination of both. For the purpose of this post, we will focus on physical pain. In later posts we will explore psychological pain and the connections between the two. That being said, much of what we will discuss here may also apply to psychological pain.

Why do we experience pain?

Most of us will be familiar with the feeling of pain. We are aware that it is not a nice feeling. When we experience pain, it can be assumed most of us would seek to relieve the pain. However, generally speaking pain can actually be quite useful. Typically, when a person feels pain they are receiving an early warning sign that something isn’t quite right in the body.

This may be that an injury to tissue is either imminent, occurring or has occurred. Therefore it is serving as a learning tool, enabling us to identify things that may be harmful. This helps us to avoid recurring or serious injuries, (Trachsel & Cascella, 2021)

Is that it?

No. As we can deduce from the updated definition of pain and the accompanying notes, pain is not always indicative of tissue damage.

Pain is a complex process within the body. There is still a lot about pain that we don’t know yet. Pain comes in many different forms. It will differ from person to person. This is one of the things that makes the complexities of pain so difficult to fully understand. Each person’s experience with pain is their own. It is completely subjective and is unique to each individual, influenced by not only physiological and psychological factors, but also social factors, (Cascella et al, 2016).

Tell me more

Pain ranges from mild, to severe, to debilitating. Some pain can last for seconds or minutes. Some last for hours, days or weeks. And for some it may last for months, years or even forever.

Shorter durations of pain is called acute pain. Usually acute pain is the result of injury.

It tends to be treatable and will heal over time. According to Amaechi, Huffman, & Fetherstone, (2021), acute pain tends to last for less than twelve weeks/three months.

If acute pain is not adequately handled it may become chronic pain, (Amaechi et al, 2021). Chronic pain is defined as pain that lasts more than 3 months or longer than an injury's expected healing period. It can also be related to long-term (chronic) illness.

A systematic review of the UK population suggested that somewhere in between one-third and one-half of people (35.0%-51.3%) are affected by chronic pain, (Fayaz, Croft, Langford, et al, 2016). They go on to suggest that this will likely increase as the population ages. In fact, pain and pain related illnesses are found to be the leading cause of disability around the world, (Vos, Allen, Arora, et al, 2017).

Whilst chronic pain is so prevalent and debilitating, progress into understanding and treating pain remains minimal. Despite thousands of years of humans experiencing pain, there is so much more we can learn.

[ahistoryofpain]

The Aims of this Blog

I am starting this blog as a bit of a passion project. I aim to research various aspect of pain in order to understand the phenomenon as a whole.

I will be aiming to look at several areas, including:

A History of Pain (how pain was viewed throughput history)

Theories of pain (scientific theories, a breakdown of evidence)

Anatomy of pain (the nervous system, areas of the brain)

Types of pain (a deeper look at acute and chronic pain and their various subcategories)

Factors of pain (things that alter perception of pain e.g. mood, culture etc.)

Causes of pain (injury, illness etc.)

Therapeutic methods (how can we treat pain?)

I am by no means an expert in the field so please feel free to correct any potential mistakes or misunderstandings. Also, feel free to request subjects for me to look at! I have an extensive list of topics to research but I am always willing to learn and study more!