Tactile thermal oral stimulation increases the cortical representation of swallowing

Background
Dysphagia is a leading complication in stroke patients causing aspiration pneumonia, malnutrition and increased mortality. Current strategies of swallowing therapy involve on the one hand modification of eating behaviour or swallowing technique and on the other hand facilitation of swallowing with the use of pharyngeal sensory stimulation. Thermal tactile oral stimulation (TTOS) is an established method to treat patients with neurogenic dysphagia especially if caused by sensory deficits. Little is known about the possible mechanisms by which this interventional therapy may work. We employed whole-head MEG to study changes in cortical activation during self-paced volitional swallowing in fifteen healthy subjects with and without TTOS. Data were analyzed by means of synthetic aperture magnetometry (SAM) and the group analysis of individual SAM data was performed using a permutation test.

Results
Compared to the normal swallowing task a significantly increased bilateral cortical activation was seen after oropharyngeal stimulation. Analysis of the chronological changes during swallowing suggests facilitation of both the oral and the pharyngeal phase of deglutition.

Conclusions
In the present study functional cortical changes elicited by oral sensory stimulation could be demonstrated. We suggest that these results reflect short-term cortical plasticity of sensory swallowing areas. These findings facilitate our understanding of the role of cortical reorganization in dysphagia treatment and recovery.

from BMC Neuroscience

The vascularization of the human cochlea: its historical background

Abstract
The history of vascularization of the human cochlea began with the first anatomical description of the cochlea in the 16th century. Three different periods are recognizable in the development of knowledge concerning this subject: the macroscopic period, with the description of the structure of the cochlea from the 16th to the 19th century; the microscopic period, with the description of the part of the organ of Corti in the 19th century; and the injection period, with the description of the fine vascularization of the cochlea in the 20th century. Various techniques were used during these three periods, which will be presented here, using only original references. This historical study reveals the ingenuity of the researchers in using different aspects of technological progress to enhance their performance in research.

http://www.biomedcentral.com/1471-2202/10/71

Provided by: The Canadian Press Written by: Lauran Neergaard, THE ASSOCIATED PRESS

WASHINGTON – The U.S. government is about to start a huge research effort to prove which are the best treatments for scores of ailments. Irregular heartbeat, prostate cancer, back pain and hearing loss lead the list of medical problems to be studied.

Choosing which treatment or test will work best for a given patient often is a guess – there’s very little good scientific evidence comparing them. As part of the economic stimulus package, the U.S. Congress set aside US$1.1 billion to start figuring that out, so patients don’t waste time and money on poor choices.

The Institute of Medicine is delivering a blueprint Tuesday of the priorities to study first.

from MedGadget.com

Talk With Kids, Not At Them

MONDAY, June 29 (HealthDay News) — If you want to help children develop language and speech skills, UCLA researchers say, listening to what they have to say is just as important as talking to them.

The effect of a conversation between a child and an adult is about six times as great as the effect of adult speech input alone, the researchers found. The results of their study appear in the July issue of Pediatrics.

“Adults speaking to children helps language develop, but what matters much more is the interaction,” said the study’s lead author, Frederick Zimmerman, an associate professor in the school of public health at the University of California, Los Angeles. “The child speaking is a big part of what drives language development. The more the child speaks, it reinforces their knowledge.”

The researchers also found that TV viewing didn’t have much of an effect — positively or negatively — as long as it wasn’t displacing conversations between an adult and a child.

That, however, may be exactly what’s happening in many homes. A study in the June issue of Archives of Pediatrics & Adolescent Medicine found that for every additional hour of television exposure, young children heard 770 fewer words from an adult. And, infants watching TV made fewer vocalizations when adults spoke to them.

The UCLA study included 275 families with children between 2 months and 48 months old. They represented a variety of incomes and education. Most families were white, with 3 percent of the families black, 8 percent Hispanic and 7 percent another non-white ethnicity.

On a randomly chosen day, parents recorded their child’s entire day, from wake-up until the child went to sleep. Each family provided about five full-day recordings during the six-month study. In addition, 71 of the families continued the study for 18 months longer.

The researchers found that, in an average day, children hear about 13,000 spoken words from adults and participated in about 400 adult-child conversations a day.

Assessed separately, factors positively associated with language development included each additional 100 conversations a day and each 1,000 word increase in the number of words spoken by adults and heard by children. When looked at alone, TV was negatively associated with language development.

But, when the three factors were analyzed together, the only one that stood out was conversation between adults and children.

“The more a child speaks and interacts with an adult, the better idea a parent has about where the child is,” Zimmerman said. “Although it’s mostly done unconsciously, parents will provide feedback and correct mistakes. They’ll also tailor their speech to the child.”

“This study supports what we recommend to families,” said Maxine Orringer, a speech-language pathologist at Children’s Hospital of Pittsburgh. “When there’s conversation, you get practice communicating. The child can make a mistake, and that helps parents understand what the child’s perception is, and it can help them correct those mistakes,” Orringer explained.

“Parents can give a child words by talking to them about what they’re doing, such as, ‘I’m putting on your pajamas now.’ But give your child the opportunity to talk, hopefully without the rest of the noise in the environment,” she added. “If parents can carve out some conversation time — maybe at bath time or at dinnertime — that’s a wonderful thing.”

Adults should remember that “sometimes it’s quicker and easier just to tell children what to do, and it’s difficult to slow down, but that’s what’s important for language development,” Zimmerman added.

“Conversation should always be a two-way street,” he said.

from the National Library for Health

Aphasia among Young Patients with Ischemic Stroke on Long-term Follow-up

Results
The study comprised 195 patients still alive after a mean follow-up of 6 years. Twenty (10.3%) patients had aphasia. Aphasia was associated with cardiac embolism (P = .007), myocardial infarction (P = .005), epilepsy (P < .001), loss of employment (P = .021), and social isolation (P = .054). On follow-up, 13 patients with aphasia underwent further assessment. These patients had all improved into milder aphasia subtypes.

Conclusion
Our study suggests that relatively few young patients with ischemic stroke have clinically significant aphasia on long-term follow-up. However, there are clinically significant differences between patients with and without aphasia that should be the focus of future research.

from

Magnet displacement: a rare complication following cochlear implantation

Abstract The purpose of this paper is to describe cases which reported complication after cochlear implantation in children: displacement of magnet from the receiver pocket, possibly aided by the use of magnetic toys. We observed magnet displacement in two female children from the same family and in one male child. Age at implantation was 23, 51, and 24 months, respectively. Magnet displacement occurred at 37, 16, and 32 months, respectively after the initial surgery. The magnets were replaced under general anaesthesia and we did not observe recurrent magnet dislodgement. Measurements indicated that forces required to remove the magnet from its pocket were not greater than those exerted by magnetic toys or the magnet used in the external sender coil. Although magnet displacement is not common after cochlear implantation, it is a major complication in children where subsequent general anaesthesia and surgery are necessary to replace the magnet. Therefore, we propose that pockets for removable magnets of cochlear implants used in children should be redesigned to increase forces to remove the magnet or that removable magnets not be used at all.

from ORL -Journal for Oto-Rhino-Laryngology and Its Related Specialties

Asymmetric Activation of Motor Cortex Controlling Human Anterior Digastric Muscles During Speech and Target-Directed Jaw Movements

Like most of the cranial muscles involved in speech, the trigeminally innervated anterior digastric muscles are controlled by descending corticobulbar projections from the primary motor cortex (M1) of each hemisphere. We hypothesized that changes in corticobulbar M1 excitability during speech production would show a hemispheric asymmetry favoring the left side, which is the dominant hemisphere for language processing in most strongly right handed subjects. Fifteen volunteers aged 24.5 ± 5.3 (SD) yr participated. All subjects were strongly right handed as reported by questionnaire. A surface electromyograph (EMG) was recorded bilaterally from digastrics and jaw movement detected by an accelerometer attached to a lower incisor. Focal transcranial magnetic stimulation (TMS) was used to assess corticomotor excitability of the digastric representation in M1 of both hemispheres during four tasks: 1) static isometric contraction of digastrics; 2) speaking a single word; 3) visually guided, nonspeech jaw movement that matched the jaw kinematics recorded during task 2; and 4) reciting a sentence. Background EMG was well matched in all tasks and jaw kinematics were similar around the time of the TMS pulse for tasks 2–4. TMS resting thresholds and digastric muscle-evoked potential (MEP) size during isometric contraction did not differ for TMS over left versus right M1. MEPs elicited by TMS over left, but not right M1 increased in size during speech and nonspeech jaw movement compared with isometric contraction. We conclude that left corticobulbar M1 is preferentially engaged for descending control of digastric muscles during speech and the performance of a rapid jaw movement to match a target kinematic profile.

from the Journal of Neurosphysiology

Comparison of Time–Frequency Responses and the Event-Related Potential to Auditory Speech Stimuli in Human Cortex

1Department of Psychology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley; and 2Department of Radiology and Biomedical Imaging and 3Department of Neurological Surgery, University of California, San Francisco, California

Submitted 23 August 2008; accepted in final form 10 May 2009

We recorded the electrocorticogram directly from the exposed cortical surface of awake neurosurgical patients during the presentation of auditory syllable stimuli. All patients were unanesthetized as part of a language-mapping procedure for subsequent left-hemisphere tumor resection. Time–frequency analyses showed significant high-gamma (high: 70–160 Hz) responses from the left superior temporal gyrus, but no reliable response from the left inferior frontal gyrus. Alpha suppression (: 7–14 Hz) and event-related potential responses exhibited a more widespread topography. Across electrodes, the suppression from 200 to 450 ms correlated with the preceding (50–200 ms) high increase. The results are discussed in terms of the different physiological origins of these electrocortical signals.

from the Journal of Neurosphysiology

Impedance Control and Its Relation to Precision in Orofacial Movement

Speech production involves some of the most precise and finely timed patterns of human movement. Here, in the context of jaw movement in speech, we show that spatial precision in speech production is systematically associated with the regulation of impedance and in particular, with jaw stiffness—a measure of resistance to displacement. We estimated stiffness and also variability during movement using a robotic device to apply brief force pulses to the jaw. Estimates of stiffness were obtained using the perturbed position and force trajectory and an estimate of what the trajectory would be in the absence of load. We estimated this “reference trajectory” using a new technique based on Fourier analysis. A moving-average (MA) procedure was used to estimate stiffness by modeling restoring force as the moving average of previous jaw displacements. The stiffness matrix was obtained from the steady state of the MA model. We applied this technique to data from 31 subjects whose jaw movements were perturbed during speech utterances and kinematically matched nonspeech movements. We observed systematic differences in stiffness over the course of jaw-lowering and jaw-raising movements that were correlated with measures of kinematic variability. Jaw stiffness was high and variability was low early and late in the movement when the jaw was elevated. Stiffness was low and variability was high in the middle of movement when the jaw was lowered. Similar patterns were observed for speech and nonspeech conditions. The systematic relationship between stiffness and variability points to the idea that stiffness regulation is integral to the control of orofacial movement variability.

from the Journal of Neurosphysiology

Resolving Precise Temporal Processing Properties of the Auditory System Using Continuous Stimuli

In natural environments complex and continuous auditory stimulation is virtually ubiquitous. The human auditory system has evolved to efficiently process an infinitude of everyday sounds, which range from short, simple bursts of noise to signals with a much higher order of information such as speech. Investigation of temporal processing in this system using the event-related potential (ERP) technique has led to great advances in our knowledge. However, this method is restricted by the need to present simple, discrete, repeated stimuli to obtain a useful response. Alternatively the continuous auditory steady-state response is used, although this method reduces the evoked response to its fundamental frequency component at the expense of useful information on the timing of response transmission through the auditory system. In this report, we describe a method for eliciting a novel ERP, which circumvents these limitations, known as the AESPA (auditory-evoked spread spectrum analysis). This method uses rapid amplitude modulation of audio carrier signals to estimate the impulse response of the auditory system. We show AESPA responses with high signal-to-noise ratios obtained using two types of carrier wave: a 1-kHz tone and broadband noise. To characterize these responses, they are compared with auditory-evoked potentials elicited using standard techniques. A number of similarities and differences between the responses are noted and these are discussed in light of the differing stimulation and analysis methods used. Data are presented that demonstrate the generalizability of the AESPA method and a number of applications are proposed.

from the Journal of Neurosphysiology

Review: Current treatment of vestibular, ocular motor disorders and nystagmus

Vertigo and dizziness are among the most common complaints with a lifetime prevalence of about 30%. The various forms of vestibular disorders can be treated with pharmacological therapy, physical therapy, psychotherapeutic measures or, rarely, surgery. In this review, the current pharmacological treatment options for peripheral and central vestibular, cerebellar and ocular motor disorders will be described. They are as follows for peripheral vestibular disorders. In vestibular neuritis recovery of the peripheral vestibular function can be improved by treatment with oral corticosteroids. In Menie`re’s disease a recent study showed long-term high-dose treatment with betahistine has a significant effect on the frequency of the attacks. The use of aminopyridines introduced a new therapeutic principle in the treatment of downbeat and upbeat nystagmus and episodic ataxia type 2 (EA 2). These potassium channel blockers presumably increase the activity and excitability of cerebellar Purkinje cells, thereby augmenting the inhibitory influence of these cells on vestibular and cerebellar nuclei. A few studies showed that baclofen improves periodic alternating nystagmus, and gabapentin and memantine, pendular nystagmus. However, many other eye movement disorders such as ocular flutter opsoclonus, central positioning, or see-saw nystagmus are still difficult to treat. Although progress has been made in the treatment of vestibular neuritis, downbeat and upbeat nystagmus, as well as EA 2, state-of-the-art trials must still be performed on many vestibular and ocular motor disorders, namely Menie`re’s disease, bilateral vestibular failure, vestibular paroxysmia, vestibular migraine, and many forms of central eye movement disorders.

from

Teaching by Listening: The Importance of Adult-Child Conversations to Language Development

RESULTS: In fully adjusted regressions, the effects of adult word count were significant when included alone but were partially mediated by adult-child conversations. Television viewing when included alone was significant and negative but was fully mediated by the inclusion of adult-child conversations. Adult-child conversations were significant when included alone and retained both significance and magnitude when adult word count and television exposure were included.

from Pediatrics

Temporal Features of Spectral Integration in the Inferior Colliculus: Effects of Stimulus Duration and Rise Time

This report examines temporal features of facilitation and suppression that underlie spectrally integrative responses to complex vocal signals. Auditory responses were recorded from 160 neurons in the inferior colliculus (IC) of awake mustached bats. Sixty-two neurons showed combination-sensitive facilitation: responses to best frequency (BF) signals were facilitated by well-timed signals at least an octave lower in frequency, in the range 16–31 kHz. Temporal features and strength of facilitation were generally unaffected by changes in duration of facilitating signals from 4 to 31 ms. Changes in stimulus rise time from 0.5 to 5.0 ms had little effect on facilitatory strength. These results suggest that low frequency facilitating inputs to high BF neurons have phasic-on temporal patterns and are responsive to stimulus rise times over the tested range. We also recorded from 98 neurons showing low-frequency (11–32 kHz) suppression of higher BF responses. Effects of changing duration were related to the frequency of suppressive signals. Signals <23 kHz usually evoked suppression sustained throughout signal duration. This and other features of such suppression are consistent with a cochlear origin that results in masking of responses to higher, near-BF signal frequencies. Signals in the 23- to 30-kHz range—frequencies in the first sonar harmonic—generally evoked phasic suppression of BF responses. This may result from neural inhibitory interactions within and below IC. In many neurons, we observed two or more forms of the spectral interactions described here. Thus IC neurons display temporally and spectrally complex responses to sound that result from multiple spectral interactions at different levels of the ascending auditory pathway.

from the Journal of Neurosphysiology

Trajectories of Receptive Language Development From 3 to 12 Years of Age for Very Preterm Children

RESULTS: From 3 to 12 years, preterm children displayed catch-up gains on the Peabody Picture Vocabulary Test-Revised. Preterm children started with an average standardized score of 84.1 at 3 years and gained 1.2 points per year across the age period studied. Growth-curve analyses of Peabody Picture Vocabulary Test-Revised raw scores revealed an indomethacin-gender effect on initial scores at 3 years, with preterm boys assigned randomly to receive indomethacin scoring, on average, 4.2 points higher than placebo-treated boys. However, the velocity of receptive vocabulary development from 3 to 12 years did not differ for the treatment groups. Children with severe brain injury demonstrated slower gains in skills over time, compared with those who did not suffer severe brain injury. Significant differences in language trajectories were predicted by maternal education and minority status.

from Pediatrics

Aphasia and text writing.

Background: Good writing skills are needed in almost every aspect of life today, and there is a growing interest in research into acquired writing difficulties. Most of the findings reported so far, however, are based on words produced in isolation. The present study deals with the production of entire texts. Aims: The aim was to characterize written narratives produced by a group of participants with aphasia. Methods & Procedures: Eight persons aged 28-63 years with aphasia took part in the study. They were compared with a reference group consisting of ten participants aged 21-30 years. All participants were asked to write a personal narrative titled ‘I have never been so afraid’ and to perform a picture-based story-generation task called the ‘Frog Story’. The texts were written on a computer. Outcome & Results: The group could be divided into participants with low, moderate, and high general performance, respectively. The texts written by the participants in the group with moderate and high writing performance had comparatively good narrative structure despite indications of difficulties on other linguistic levels. Conclusions & Implications: Aphasia appeared to influence text writing on different linguistic levels. The impact on overall structure and coherence was in line with earlier findings from the analysis of spoken and written discourse and the implication of this is that the written modality should also be included in language rehabilitation.

from the International Journal of Language and Communication Disorders