Friday, September 19, 2014

The neuroscience behind scratching an itch

The beautiful experience of alleviating an itch, the vigorous scratching of skin cells, and the white flakes that float away slowly and gently like a whimsical dream.

If only those with chronic itching problems could describe their conditions in such a serene way. In the latest edition of Nature Neuroscience, Diana Bautista and colleagues (2014) review the literature on the underlying mechanism of the itch at the molecular and cellular level within the peripheral and central nervous systems. They describe what drives acute and chronic itching and even quote the famous Buddhist Nagarjuna in their abstract.

"There is a pleasure when an itch is scratched. But to be without an itch is more pleasurable still".



They provide the reader with a few examples of neurological disorders where chronic itching can become a problem:

1. multiple sclerosis
2. diabetic neuropathy
3. shingles

They also boldly state that the act of itching serves no biological purpose.

Because I currently do not have institutional access to any research journals, I can only surmise that this article is an incredibly interesting read (although there is a greater likelihood that the details would go over my head). But alas, I now suffer from an inability to rid myself of this nagging itch to read Bautista et al.'s article so that I can write a decent blog post about it.

You can check out the first page here.

You can also enjoy this Times read on the mysteries of the itch and how a molecule known as a neuropeptide natriuretic polypeptide b (Nppb) plays a crucial role in the itching process.

References:

Bautista, D., Wilson, S., & Hoon, M. (2014). Why we scratch an itch: the molecules, cells and circuits of itch Nature Neuroscience, 17 (2), 175-182 DOI: 10.1038/nn.3619

The above image is from http://www.byebyedoc.com/wp-content/uploads/2013/04/itching.jpeg

Thursday, August 21, 2014

How to prevent a possible concussion from the ALS ice bucket challenge



The ice bucket challenge has swept the nation in an effort to raise awareness for ALS. However, there seems to have been a number of concussions (or mild traumatic brain injuries) sustained from performing a seemingly altruistic act. Although some people may find the below video funny, concussions are a serious issue and can lead to serious consequences including executive dysfunction. Symptoms can include short loss of consciousness, feeling dazed and confused, loss of immediate memory, headaches, blurry vision, slurred speech, concentration difficulties, fatigue, and sleep disturbance.

https://www.youtube.com/watch?v=bNl9suOVV0w

Two recent meta-analyses (one examining neuropsychological performance while the other examining fMRI data) have in fact supported the claim that executive functioning can be negatively impacted after a mild traumatic brain injury (Carr et al., 2014; Eierud et al., 2014), although, there has been long-standing controversy regarding whether a mild traumatic brain injury can lead to long-term effects (Rohling et al., 2012).

Nevertheless, appropriate guidelines should be established regarding how to safely execute the ice bucket challenge. Thus, I propose the following recommendations (this is by no means an exhaustive list):

1) At least two people should be holding the bucket
2) There should be absolutely no throwing or dropping of the bucket
3) The ice cubes should be crushed
4) The distance from bucket to head should be no greater than 3 ft high

...and finally

5) Don't be an idiot about it

I've treated too many unfortunate individuals who've sustained traumatic brain injuries to find the humor in "ice bucket challenge fails" (as shown above). All of this is supposed to support the treatment of a serious medical condition, not cause one. It's interesting that in raising awareness for ALS, we now have to raise awareness for traumatic brain injury.

You can find the full Karr et al. (2014) paper here.

References:

Eierud C, Craddock RC, Fletcher S, Aulakh M, King-Casas B, Kuehl D, & LaConte SM (2014). Neuroimaging after mild traumatic brain injury: Review and meta-analysis. NeuroImage. Clinical, 4, 283-94 PMID: 25061565

Karr JE, Areshenkoff CN, & Garcia-Barrera MA (2014). The neuropsychological outcomes of concussion: a systematic review of meta-analyses on the cognitive sequelae of mild traumatic brain injury. Neuropsychology, 28 (3), 321-36 PMID: 24219611

Rohling, M., Larrabee, G., & Millis, S. (2012). The “Miserable Minority” Following Mild Traumatic Brain Injury: Who Are They and do Meta-Analyses Hide Them? The Clinical Neuropsychologist, 26 (2), 197-213 DOI: 10.1080/13854046.2011.647085

The above image is from http://imgur.com/tcv0cWT


Saturday, July 12, 2014

Night-to-night variability of sleep in traumatic brain injury

It's been a while since I've posted something substantial. My apologies to all 20 followers of TQLC. Academia and clinical cases have been taking up most of my time. However, some exciting news! My paper on variability of respiration during sleep in traumatic brain injury (TBI) has recently been accepted into Neurorehabilitation. 

In the paper my colleagues and I examined the sleep processes of individuals with TBI using polysomnography. Polysomnography is a tool used to measure biophysical changes during sleep and diagnose disorders such as obstructive sleep apnea in which breathing repeatedly stops and starts during sleep, a big problem for individuals with TBI. The contraption is quite uncomfortable (as you can see by the image) and takes some getting used to. Thus, we looked at the "first-night effects" of polysomnography on our subjects to see if the measurements from night-to-night were reliable. 

We found that polysomnography was quite reliable on the first night compared to the second night, especially for diagnosing obstructive sleep apnea. This isn't typically the case for the general population so we were a bit surprised. There are a few possible explanations for why individuals with TBI don't seem to experience such first-night effects. One reason is that after a TBI, sleep becomes disrupted due to biological changes in the brain that regulate sleep processes. Thus, when our sample entered the sleep lab, their sleep remained poor on night 1 AND night 2 with little change. 

A second possible explanation may be that they were unaffected by novel external environmental stimuli such as the uncomfortable sensors they had to wear or the fact that they weren't in their own bedroom. This explanation is supported by the fact that individuals with TBI tend to have higher amounts of slow-wave sleep (the deep, restful kind). However, our subjects still tended to complain of sleep disturbances and daytime fatigue. Quite the mystery and something that needs to be further explored. I would love to hear your thoughts.

Here is a link to the uncorrected abstract. http://www.ncbi.nlm.nih.gov/pubmed/24990025

References:

Lu W, Cantor J, Aurora RN, Nguyen M, Ashman T, Spielman L, Ambrose A, Krellman J, & Gordon W (2014). Variability of respiration and sleep during polysomnography in individuals with TBI. NeuroRehabilitation PMID: 24990025

Monday, June 30, 2014

An influential reading



A question posed over at neuroecology. "So what readings have influenced you?"
My response: 
Joseph Goldstein’s Insight Meditation: The Practice of Freedom. It inspired me to further investigate why we, as humans, contribute to our own suffering and how to awaken from this dilemma. Thus, I became a psychologist interested in studying sleep processes.

Sunday, March 9, 2014

Lack of sleep impairs emotion recognition

This is a re-post of an entry I had written exactly 4 years ago. I liked it so much I decided to share it again. The ability to read emotions is an important part of the human experience; the only way to successfully navigate through complex social environments. It comes in handy especially if you don the title of psychotherapist or professional poker player. Without it, you are rendered socially inept. You enter the world of the autistic individual.

Thanks to Charles Darwin we now know that it’s not just the eyes that are “the windows to the soul”. He first wrote about the subject of facial expressions in his 1898 book titled The Expression of the Emotions in Man and Animals (the link includes the work in its entirety). In it he described the emotions conveyed in the face as being both universal and “species-specific”.

Saturday, February 15, 2014

Blasting long-term potentiation with a Mega Buster

Mega Man (1987) was one of the most entertaining games that I remember ever playing on Nintendo. You were Dr. Light's boy android (think Astro Boy or Pinocchio) and your mission was to defeat the multitude of robot bosses threatening to destroy the world. However, the only way to defeat them was to 1) consider how to counteract their special abilities with your own abilities and 2) memorize their attack patterns, often taking hours of learning (and frustration) before you got it right. Once successful, you would acquire that particular bosses' special ability, thus expanding your arsenal, and move on to fight another epic battle (not unlike Highlander). While reading Alvarez-Salvado and colleagues' (2014) paper on fMRI and long-term potentiation (LTP), it reminded me of this game. The vivid childhood memory was triggered by my reading of their abstract in which they wrote:

Neurons are able to express long-lasting and activity-dependent modulations of their synapses. This plastic property supports memory and conveys an extraordinary adaptive value, because it allows an individual to learn from, and respond, to changes in the environment.

Without this critical process of the brain, neither I nor Rock (the boy android) could have defeated Dr. Wily's evil robots and ultimately save the world from utter destruction. In Alvarez-Solvado and his colleagues' paper, they discuss how both cellular changes and network interactions in the brain are needed to encode a pattern of neuronal activity into long-term memory through synaptic plasticity. They go on to state that although the field of neuroscience already knows a great deal about the relationship between cellular changes and long-term memory, less is known about how regulation of network interactions effect plasticity. Thus, they were interested in looking at this mechanism a bit further using their version of a Mega Buster; a combination of high resolution functional magnetic resonance imaging (fMRI) and in vivo electrophysiology, in rats.

The team triggered LTP-induced network reorganization between the hippocampus (a seahorse shaped brain structure involved in learning and memory) and neocortical ("new brain") structures such as the prefrontal cortex (involved in executive functions such as planning and organization) and the sub cortical nucleus (involved in voluntary movement). They found that there was an enhancement of connection between these two brain regions via stimulation of the perforant pathway. The perforant pathway is a connective route between the entorhinal cortex to all fields of the hippocampus (think about the entorhinal cortex as the major highway between the hippocampus and the neocortex and the perforant pathway as the exit off the entorhinal cortex highway leading to the hippocampus). The perforant pathway plays a significant role in spatial memory and learning.

Image of perforant pathway from Learning and Memory16: 504-507

More specifically, Alvarez-Solvado et al. observed, through their high-res imaging, a fast increase in communication between the hippocampus and the prefrontal cortex mediated by N-methyl-D-aspartate (NMDA) receptors, the predominant molecular device for controlling synaptic plasticity and memory. From this finding they suggest that there may be two memory buffers functioning in parallel during memory encoding. They also observed that when LTP-induction was triggered on one side of the hippocampus, there was functional activation on the other side of hippocampus as well, supported by white matter structures that connect hemispheres of the brain. They believe this finding may represent bilateral coordination of associational networks with a role in pattern separation and sequence learning, all critical skills to have if you want to beat a game like Mega Man (and accomplish more important things, of course).

Reference:
Alvarez-Salvado E, Pallarés V, Moreno A, & Canals S (2014). Functional MRI of long-term potentiation: imaging network plasticity. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 369 (1633) PMID: 24298154

Daumas S, Ceccom J, Halley H, Francés B, & Lassalle JM (2009). Activation of metabotropic glutamate receptor type 2/3 supports the involvement of the hippocampal mossy fiber pathway on contextual fear memory consolidation. Learning & memory (Cold Spring Harbor, N.Y.), 16 (8), 504-7 PMID: 19638469

Sunday, February 9, 2014

Forever alone disorder

Valentines Day is soon upon us. However, quite a few individuals, also known as otakus, could care less. During college I met some people who you might consider otakus or dorks. They never left their dorm rooms because they were just THAT into their video games. They would play for hours/days, completely disinterested in socializing with real people, partying, attending classes, and sometimes even eating. Although I didn't know it at the time, there was a name for this kind of strange and extreme "loner" behavior. For those of you who are unfamiliar with hikikomori, it is a recently recognized type of mental illness that has been rampant in locations like Japan. It refers to adolescent or young adult males who completely withdraw from social life and remain completely isolated, typically staying in their rooms for months on end. The criteria include:
1) spending most of the day and nearly every day confined to home 
2) marked and persistent avoidance of social situations
3) symptoms interfering significantly with the person’s normal routine, occupational (or academic) functioning, or social activities or relationships
4) perceiving the withdrawal as 
ego-syntonic
5) duration at least six months
6) no other mental disorder that accounts for the social withdrawal and avoidance. 
It is quite a serious issue and is linked to autism, pervasive developmental disorder, societal and cultural influences. 
I have heard of some cases happening here in the US  and Spain as well. Ovejero and colleagues (2013) provide a case study in which a young Spanish man was socially isolated for four years. He kept his room in an orderly fashion, was well groomed, and kept active within his home (although the article does not specify how he spent his time, I would put my money on World of Warcraft). There was no evidence of any other psychological disorder (e.g. schizophrenia, social phobia, anxiety, depression). The man stated that he was ashamed to leave his room because he had no teeth. He explained that his fear of needles prevented him from receiving dental prostheses. 
Below are some videos that nicely depict hikikomori. The first video is an illustration as to what the life of an individual "suffering" from hikikomori may look like.The second video is a commentary on hikikomori. The critical question that I have in mind is whether hikikomori should really be considered a disorder since the individual isn't really suffering per se. They actually quite enjoy being by themselves. Perhaps the "disorder" is due to the fact that they are not "productive" citizens of society. However, what if they were able to generate an income through something like internet services? I've heard of people who make a living by playing video games and streaming their performance live while receiving donations from dedicated viewers and fans (twitch.tv).

Video 1:
http://m.youtube.com/watch?v=50Y7R5zP0wc












References:
Ovejero S, Caro-Cañizares I, de León-Martínez V, & Baca-Garcia E (2013). Prolonged social withdrawal disorder: A hikikomori case in Spain. The International journal of social psychiatry PMID: 24101742

First image taken from http://lonerwolf.com/hikikomori-japans-young-hermits/

Sunday, September 1, 2013

Just a mild electric current through the brain to increase memory gain

Have you ever watched that compelling infomerical selling the incredible electrical muscle stimulator, the Tone-A-Matic, promising beautiful rippling abs to couch potatotes all around the world? Ever hope something similar would work for the brain? Well folks, you're in luck!

There has been mounting evidence that transcranial direct current stimulation can improve cognitive functioning (Boggio et al., 2006; Brasil-Neto et al., 2012; Javadi et al., 2012, 2013). However, many of the studies used single stimulation sessions with only transient effects.

Meinzer and colleagues (2013), from Charite University in Germany, looked to fix this very issue. They investigated the effects of anodal transcranial direct current stimulation over multiple days on 20 very lucky people. They found that mild electrical stimulation to the brain, right after the learning sessions, enhanced language learning over time for both familiar and novel words. But wait! That's not all. They also observed that the effects lasted over an extended period of time. They suggest that this technology could possibly benefit stroke patients during rehabilitation. 

I, for one, truly need this in my life. Especially right after learning someones name. Maybe a cheap DIY 9-volt electrical stimulator would work just as well? Then again, knowing my luck, maybe not. I'll stick with using mnemonics, for now. 

References:

Boggio PS, Ferrucci R, Rigonatti SP, Covre P, Nitsche M, Pascual-Leone A, & Fregni F (2006). Effects of transcranial direct current stimulation on working memory in patients with Parkinson's disease. Journal of the neurological sciences, 249 (1), 31-8 PMID: 16843494

Brasil-Neto JP (2012). Learning, memory, and transcranial direct current stimulation. Frontiers in psychiatry, 3 PMID: 22969734

Javadi AH, Cheng P, & Walsh V (2012). Short duration transcranial direct current stimulation (tDCS) modulates verbal memory. Brain stimulation, 5 (4), 468-74 PMID: 21962975

Javadi AH, & Cheng P (2013). Transcranial direct current stimulation (tDCS) enhances reconsolidation of long-term memory. Brain stimulation, 6 (4), 668-74 PMID: 23137702

Meinzer M, Jähnigen S, Copland DA, Darkow R, Grittner U, Avirame K, Rodriguez AD, Lindenberg R, & Flöel A (2013). Transcranial direct current stimulation over multiple days improves learning and maintenance of a novel vocabulary. Cortex; a journal devoted to the study of the nervous system and behavior PMID: 23988131

Friday, August 30, 2013

Cognitive phenotypes in TBI

There are many different ways to categorize individuals with TBI in terms of clinical severity, mechanism of injury, and pathophysiology; each of which may impact prognosis and treatment (Hempill, 2013). The initial evaluation of individuals with TBI typically includes GCS, CT scan, and a neurologic exam (Saatman et al., 2008). However, the primary concern with these current diagnostic methods is that they lack specificity in terms of functional impairment and treatment selection. 

A possible solution to this problem could be to develop and implement a sub-classification system using cognitive taxonomies. This will allow for reliable clustering of individuals into meaningful groups, as seen in previous work with temporal lobe epilepsy and autism (Hermann et al., 2007, Tager-Flusberg et al., 2003; Losh et al., 2009). 


A taxonomic approach provides a common language among professionals within the field and facilitates refined investigations of both clinical and neurobiological correlates of TBI. Furthermore, taxonomies serve to improve the identification of appropriate treatment options. Limited research  on cognitive taxonomic classification in TBI has been conducted thus far. 


In a previous study, Goldstein et al. (2010) collected neuropsychological data from war veterans using the Halstead-Reitan and WAIS-R batteries. They observed that neuropsychological profiles were mainly heterogeneous and primarily linked to demographic variables. Using cluster analysis, they observed three categories (near normal, moderately impaired, and globally impaired). However, data was collected before 1997 and the neuropsychological tests used were outdated. In addition,  their sample was limited to a male veteran population. 

Thus, with more contemporary tests of cognitive domains and a diversified sample of individuals with TBI, we would possibly see increased heterogeneity and specificity of cognitive phenotypes.   

References:


Goldstein G, Allen DN, & Caponigro JM (2010). A retrospective study of heterogeneity in neurocognitive profiles associated with traumatic brain injury. Brain injury : [BI], 24 (4), 625-35 PMID: 20235765

Hermann B, Seidenberg M, Lee EJ, Chan F, & Rutecki P (2007). Cognitive phenotypes in temporal lobe epilepsy. Journal of the International Neuropsychological Society : JINS, 13 (1), 12-20 PMID: 17166299


Saatman KE, Duhaime AC, Bullock R, Maas AI, Valadka A, Manley GT, & Workshop Scientific Team and Advisory Panel Members (2008). Classification of traumatic brain injury for targeted therapies. Journal of neurotrauma, 25 (7), 719-38 PMID: 18627252


Tager-Flusberg H, & Joseph RM (2003). Identifying neurocognitive phenotypes in autism. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 358 (1430), 303-14 PMID: 12639328


http://www.uptodate.com/contents/traumatic-brain-injury-epidemiology-classification-and-pathophysiology#H4




Tuesday, January 8, 2013

Loss of consciousness subsequent to chronic nose-blowing


The case of a patient with OCD who blew his nose way too often: 

The case is described of a 50-year-old man, treated for 10 years in an outpatient psychiatric clinic for an obsessive compulsive disorder, who presented with acute loss of consciousness after forceful nose blowing. A CT scan revealed an intraparenchymal air collection with tension signs in the left frontal lobe and a bone defect in the roof of the ethmoid sinus. After emergency left frontal craniotomy and dura opening, the gaseous collection was evacuated by a ventricular catheter inserted into the brain and the bone defect was repaired with pericranium flap and muscle. The postoperative course was uneventful with neurocognitive improvement and regained motility. Spontaneous tension pneumocephalus is a rare life-threatening condition which is often caused by a bone defect near the tegmen tympani. This case illustrates both an unusual cause and a unique surgical treatment for spontaneous tension intraparenchymal pneumocephalus. It can be a dangerous entity with potential for early mortality and long-term morbidity if not promptly decompressed. The pathogenesis, diagnosis and surgical strategies for spontaneous tension pneumocephalus are briefly discussed. 


Mirone G, Rotondo M, Scuotto A, et al. Spontaneous intraparenchymal tension pneumocephalus triggered by compulsive forceful nose blowing. Emerg Med J. 2009;26(11):837-838

Beware of cheerleading



An article on the dangers of cheerleading and the critical height in which one can sustain a brain injury. And who said this sport was for wusses?

CONTEXT: Although playground surfaces have been investigated for fall impact attenuation, the surfaces that cheerleaders use have received little attention. 

OBJECTIVE: To determine (1) the critical height for selected surfaces used by cheerleaders at or below which a serious head impact injury from a fall is unlikely to occur, (2) the critical heights for non-impact-absorbing surfaces for comparison purposes, and (3) the effect of soil moisture and grass height on g(max) (which is defined as the multiple of g [acceleration due to gravity at the earth's surface at sea level: ie, 32.2 feet x s(-1) x s(-1)] that represents the maximum deceleration experienced during an impact) and the Head Injury Criterion (HIC) at the critical height for a dry grass surface. 

DESIGN: Observational study. SETTINGS: A local cheerleading gym, indoor locations within the authors' institution, and various outdoor locations. MAIN OUTCOME MEASURE(S): g(max), HIC, and critical height. 

RESULTS: Critical heights for the surfaces tested ranged from 0.5 ft (0.15 m) for concrete and vinyl tile installed over concrete to more than 11 ft (3.35 m) for a spring floor. Increases in grass height and soil moisture resulted in an increase in the critical height for grass surfaces. Only spring floors and 4-in (0.10-m)-thick landing mats placed on traditional foam floors had critical heights greater than 10.5 ft (3.20 m), thus providing enough impact-absorbing capacity for performance of 2-level stunts. 

CONCLUSIONS: The potential for serious head impact injuries can be minimized by increasing the shock-absorbing capacity of the surface, decreasing the height from which the person falls, or both. Cheerleaders and cheerleading coaches should use the critical heights reported in this study to compare the relative impact-absorbing capacities of the various surfaces tested, with critical height as an indicator of the impact-absorption capacity of the surface. The findings of this study can be used to select the most appropriate surface for the type of maneuver to be performed, based on the maximum height expected to be achieved by the cheerleader(s) during execution of the maneuver. Cheerleaders should not perform maneuvers at heights that exceed the critical height for the surface on which they are performing. 

Shields BJ, Smith GA. The potential for brain injury  on selected surfaces used by cheerleaders. J Athl Train. 2009;44(6):595-602

Monday, January 7, 2013

Weapon swallowing as a form of stress relief


Another fascinating case study. Patient with intellectual disability who swallowed sharp objects to reduce stress. If only this solution was a viable option to end world violence...

A 41-year-old male patient with intellectual disabilities presented after having swallowed approximately 20 sharp objects. While admitted to a psychiatric ward, surgeons removed a glove from his stomach endoscopically and pharmacologically facilitated the objects' complication-free bowel passage. The patient explained the swallowing as a means to release himself from tension induced by stress. His aberrant behavior also seemed to serve as a means to exert pressure on psychosocial workers. Other deviations included the pushing of sharp objects under the skin and multiple paraphiliae. As a child, the patient suffered from early psychological and physical traumatization. Both parents were allegedly physically abusive alcoholics.  Apart from possible alcohol embryopathy and traumatic brain damage, meningitis, which the patient had at the age of three, is discussed as the most likely reason for his oligophrenia, associated with left-sided, temporo-parietal atrophy and epilepsy. 

te Wildt BT, Tettenborn C, Schneider U, et al. Swallowing foreign bodies as an example of impulse control disorder in a patient with intellectual disabilities: A case report. Psychiatry (Edgemont). 2010;7(9):34-37

Saturday, December 15, 2012

Compulsive carnival song whistling


Another fascinating research article!


Compulsive carnival song whistling following cardiac arrest: a case study

A. Rosaura PolakJasper W. van der PaardtMartijn FigeeNienke VulinkPelle de KoningMiranda Olff andDamiaan Denys
BMC Psychiatry 2012, 12:75 doi:10.1186/1471-244X-12-75

Background

Compulsivity is the repetitive, irresistible urge to perform a behavior, the experience of loss of voluntary control over this intense urge and the tendency to perform repetitive acts in a habitual or stereotyped manner. Compulsivity is part of obsessive-compulsive disorder (OCD), but may occasionally occur as stand-alone symptom following brain damage induced by cardiac arrest. In this case report, we describe a patient who developed compulsivity following cardiac arrest. We review diagnostic options, underlying mechanisms and possible treatments.

Case presentation

A 65-year-old man presented at our clinic with continuous compulsive whistling following cardiac arrest. Neither obsessive-compulsive symptoms, nor other psychiatric complaints were present prior to the hypoxic incident. An EEG showed diffuse hypofunction, mainly in baso-temporal areas. Treatment with clomipramine resulted in a decrease of whistling.

Discussion

This case report illustrates de novo manifestation of compulsivity following cardiac arrest and subsequent brain damage and gives additional information on diagnostic options, mechanisms and treatment options. Differential diagnosis between stereotypies, punding, or OCD is difficult. Compulsivity following brain damage may benefit from treatment with serotonin reuptake inhibitors. This finding enhances our knowledge of treatments in similar cases.

Tuesday, December 11, 2012

Why it's ok for Richard to touch Joan

Denman A, Wilkinson R. Applying conversation analysis to traumatic brain injury: Investigating touching another person in everyday social interaction. Disabil Rehabil. 2011;33(3):243-252

PURPOSE: Touching others, particularly the opposite sex, is a relatively common and problematic behaviour evident in many people with traumatic brain injury (TBI), in particular males. Here, we analyse this behaviour in a man with TBI (Richard) who regularly engages in inappropriate touching of women. The article draws on video-recordings of two naturally occurring social interactions between Richard and Joan (one of his carers) to analyse all six instances within these interactions where Richard touches Joan. METHOD: The recordings were made by leaving a video-recorder in Richard's home where he is supported by members of a care team. The socio-linguistic method of conversation analysis was used to transcribe and analyse the data. RESULTS: The analysis shows that each of the six instances of the touching behaviour occurred not as a random or isolated event in the interaction but rather in accompaniment with talk as part of a particular conversational action. Specifically, the conversational action in each case was produced in an emphatic or heightened style, with this style constituted by Richard touching Joan as well as by his use of a number of other resources such as eye gaze and the use of stress. CONCLUSIONS: The analysis suggests that the touching behaviours in this case were linked not so much to physical opportunities (which were available through much of these interactions) but rather to what conversational action was being produced at that particular sequential context within the interaction. For example, several instances of touching occurred as part of emphatically produced conversational actions where a previous, non-emphatic, production of that action had not been accepted or responded to by Joan. Clinical implications, such as suggestions for prophylactic management on the part of those interacting with people with TBI, are discussed.

Maple syrup urine disease. Who knew?

I've been tasked with sorting through thousands of articles in order to contribute to a systematic review on the treatment of psychiatric disorders in traumatic brain injury patients. Through this process I've stumbled upon a few fascinating and sometimes "out there" articles. For the next couple of weeks I'll be posting up abstracts that really caught my eye. We begin with Mescka and colleagues 2011 study on maple syrup urine disease; it's not what you think.

Maple syrup urine disease (MSUD) is an autosomal recessive inborn error of metabolism caused by deficiency of the activity of the mitochondrial enzyme complex branched-chain alpha-keto acid dehydrogenase (BCKAD) leading to accumulation of the branched-chain amino acids (BCAA) leucine, isoleucine and valine and their corresponding branched-chain alpha-keto acids. Affected patients present severe brain dysfunction manifested such as ataxia, seizures, coma, psychomotor delay and mental retardation. The mechanisms of brain damage in this disease remain poorly understood.

Mescka, C., Moraes, T., Rosa, A., Mazzola, P., Piccoli, B., Jacques, C., Dalazen, G., Coelho, J., Cortes, M., Terra, M., Regla Vargas, C., & Dutra-Filho, C. (2011). In vivo neuroprotective effect of L-carnitine against oxidative stress in maple syrup urine disease Metabolic Brain Disease, 26 (1), 21-28 DOI: 10.1007/s11011-011-9238-x