A Patient With Bipolar Illness and Her Neuropsychological Signature

from Clinical Case Studies

This article describes a case study in which neuropsychological assessment was carried out on a 30-year-old, previously diagnosed, bipolar female to determine existence of specific deficits in cognitive function. The patient, whose mood cycles were 12 hours to 24 hours, was subsequently evaluated 8 hours per day for 5 consecutive days (a complete work week of neuropsychological assessment). Neuropsychological results showed motor slowing, right hemispheric dysfunctioning, and memory problems during depressive periods and attentional and executive problems during hypomanic and manic periods. The most normal performance was found during euthymic periods. In addition, left and right hemi visual neglect, aphasia, and sensorimotor problems were present across all mood states. Treatment implications are subsequently described.

Vestibular signal processing in a proprioceptively deafferented subject: The case of sitting posture

from BMC Neurology

Background

The vestibular system of the inner ear provides information about head translation/rotation in space and about the orientation of the head with respect to the gravitoinertial vector. It also largely contributes to the control of posture through vestibulospinal pathways. Testing an individual severely deprived of somatosensory information below the nose, we investigated if equilibrium can be maintained while seated on the sole basis of this information.

Results

Although she was unstable, the deafferented subject (DS) was able to remain seated with the eyes closed in the absence of feet, arm and back supports. However, with the head unconsciously rotated towards the left or right shoulder, the DS’s instability markedly increased. Small electrical stimulations of the vestibular apparatus produced large body tilts in the DS contrary to control subjects who did not show clear postural responses to the stimulations.

Conclusions

The results of the present experiment show that in the lack of vision and somatosensory information, vestibular signal processing allows the maintenance of an active sitting posture (i.e. without back or side rests). When head orientation changes with respect to the trunk, in the absence of vision, the lack of cervical information prevents the transformation of the head-centered vestibular information into a trunk-centered frame of reference of body motion. For the normal subjects, this latter frame of reference enables proper postural adjustments through vestibular signal processing, irrespectively of the orientation of the head with respect to the trunk.

Effects of Selective Attention on the Electrophysiological Representation of Concurrent Sounds in the Human Auditory Cortex

from the Journal of Neuroscience

In noisy environments, we use auditory selective attention to actively ignore distracting sounds and select relevant information, as during a cocktail party to follow one particular conversation. The present electrophysiological study aims at deciphering the spatiotemporal organization of the effect of selective attention on the representation of concurrent sounds in the human auditory cortex. Sound onset asynchrony was manipulated to induce the segregation of two concurrent auditory streams. Each stream consisted of amplitude modulated tones at different carrier and modulation frequencies. Electrophysiological recordings were performed in epileptic patients with pharmacologically resistant partial epilepsy, implanted with depth electrodes in the temporal cortex. Patients were presented with the stimuli while they either performed an auditory distracting task or actively selected one of the two concurrent streams. Selective attention was found to affect steady-state responses in the primary auditory cortex, and transient and sustained evoked responses in secondary auditory areas. The results provide new insights on the neural mechanisms of auditory selective attention: stream selection during sound rivalry would be facilitated not only by enhancing the neural representation of relevant sounds, but also by reducing the representation of irrelevant information in the auditory cortex. Finally, they suggest a specialization of the left hemisphere in the attentional selection of fine-grained acoustic information. 

Hearing from Inside: The Latest on Otologics Prosthesis

from MedGadget.com

To update our readers, The MIT Technology Review has an article on a fully implantable hearing prosthesis from Otologics that we wrote about a year ago.

The device is powered by a battery that is recharged when the user places a small radio transmitter against his or her head for 60 to 90 minutes. The transmitter is held to the skin by a magnet in the implant. An inductive coil in the implant converts the radio energy to electricity and recharges the battery with it. The battery can stay inside the body for at least five years, according to the company, before it needs to be replaced. The implanted components are hermetically sealed together to protect against leaks, so the electronics, microphone, and inductive coil are replaced as well. However, the piston in the middle ear remains in place.The results of a phase I clinical trial of the hearing aid were reported in the August 2007 issue of Otolaryngology–Head and Neck Surgery. Twenty subjects with moderate to severe hearing loss were implanted in one ear. (Seventeen of the subjects had worn conventional hearing aids prior to the study.) The subjects did somewhat worse than with the hearing aid they had previously worn: their ability to hear a range of single-frequency tones dropped between 5 and 12 decibels, and mean word-recognition scores dropped from the low 80 percent range to the high 60 percent range.

On the other hand, a satisfaction survey found that the subjects felt that the device not only improved their hearing, but also sounded more natural than their old hearing aid. The authors of the study speculated that new processing algorithms would improve the test results. Otologics has indicated that it is already working on this.

Aid boost for hearing research

from News-Medical.net

Research at the University of Essex into aiding people with hearing impairments has won a grant of nearly half a million pounds.

Professor Ray Meddis of the Department of Psychology and his team of Wendy Lecluyse and Robert Ferry, have been awarded £447,000 by the Engineering and Physical Sciences Research Funding council to develop a computerised hearing dummy. In addition, they have been given £50,000 by the Deafness Research Council.

Young children associate novel words with complex objects rather than salient parts

from Developmental Psychology

How do children learn associations between novel words and complex perceptual displays? Using a visual preference procedure, the authors tested 12- and 19-month-olds to see whether the infants would associate a novel word with a complex 2-part object or with either of that object’s parts, both of which were potentially objects in their own right and 1 of which was highly salient to infants. At both ages, children’s visual fixation times during test were greater to the entire complex object than to the salient part (Experiment 1) or to the less salient part (Experiment 2)–when the original label was requested. Looking times to the objects were equal if a new label was requested or if neutral audio was used during training (Experiment 3). Thus, from 12 months of age, infants associate words with whole objects, even those that could potentially be construed as 2 separate objects and even if 1 of the parts is salient. (PsycINFO Database Record (c) 2007 APA, all rights reserved)

This cat has nine lives? Children’s memory for genericity in language

from Developmental Psychology

Generic noun phrases (”Birds lay eggs”) are important for expressing knowledge about abstract kinds. The authors hypothesized that genericity would be part of gist memory, such that young children would appropriately recall whether sentences were presented as generic or specific. In 4 experiments, preschoolers and college students (N = 280) heard a series of sentences in either generic form (e.g., “Bears climb trees”) or specific form (e.g., “This bear climbs trees”) and were asked to recall the sentences following a 4-min distractor task. Participants in all age groups correctly distinguished between generic and specific noun phrases (NPs) in their recall, even when forgetting the details of the NP form. Memory for predicate content (e.g., “climb trees”) was largely unaffected by genericity, although memory for category labels (e.g., “bear”) was at times better for those who heard sentences with generic wording. Overall, these results suggest that generic form is maintained in long-term memory even for young children and thus may serve as the foundation for constructing knowledge about kinds. (PsycINFO Database Record (c) 2007 APA, all rights reserved)

The varieties of speech to young children

from Developmental Psychology

This article examines caregiver speech to young children. The authors obtained several measures of the speech used to children during early language development (14-30 months). For all measures, they found substantial variation across individuals and subgroups. Speech patterns vary with caregiver education, and the differences are maintained over time. While there are distinct levels of complexity for different caregivers, there is a common pattern of increase across age within the range that characterizes each educational group. Thus, caregiver speech exhibits both long-standing patterns of linguistic behavior and adjustment for the interlocutor. This information about the variability of speech by individual caregivers provides a framework for systematic study of the role of input in language acquisition. (PsycINFO Database Record (c) 2007 APA, all rights reserved)

Language access and theory of mind reasoning: Evidence from deaf children in bilingual and oralist environments

from Developmental Psychology

This investigation examined whether access to sign language as a medium for instruction influences theory of mind (ToM) reasoning in deaf children with similar home language environments. Experiment 1 involved 97 deaf Italian children ages 4-12 years: 56 were from deaf families and had LIS (Italian Sign Language) as their native language, and 41 had acquired LIS as late signers following contact with signers outside their hearing families. Children receiving bimodal/bilingual instruction in LIS together with Sign-Supported and spoken Italian significantly outperformed children in oralist schools in which communication was in Italian and often relied on lipreading. Experiment 2 involved 61 deaf children in Estonia and Sweden ages 6-16 years. On a wide variety of ToM tasks, bilingually instructed native signers in Estonian Sign Language and spoken Estonian succeeded at a level similar to age-matched hearing children. They outperformed bilingually instructed late signers and native signers attending oralist schools. Particularly for native signers, access to sign language in a bilingual environment may facilitate conversational exchanges that promote the expression of ToM by enabling children to monitor others’ mental states effectively. (PsycINFO Database Record (c) 2007 APA, all rights reserved)

It’s a sign of the kind: Gestures and words guide infants’ inductive inferences

from Developmental Psychology

The role of words and gestures in guiding infants’ inductive inferences about nonobvious properties was examined. One hundred seventy-two 14-month-olds and 22-month-olds were presented with novel target objects followed by test objects that varied in similarity to the target. Objects were introduced with a novel word or a novel gesture or with no label. When target and test objects were highly similar in shape, both 14- and 22-month-olds inferred that these objects shared a nonobvious property, regardless of whether the objects were labeled with a word or a gesture or with no label. When objects were labeled with the same word, both 14- and 22-month-olds generalized the nonobvious properties to objects that shared minimal perceptual similarity. Finally, when objects were labeled with the same gesture, 14-month-olds, but not 22-month-olds, generalized the nonobvious properties to objects that shared minimal perceptual similarity. These results indicate that 14-month-olds possess a more generalized symbolic system as they will rely on both words and gestures to guide their inferences. By 22-months of age, infants treat words as a privileged referential form when making inductive inferences. (PsycINFO Database Record (c) 2007 APA, all rights reserved)

Do 9-month-old infants expect distinct words to refer to kinds?

from Developmental Psychology

In 3 experiments, 9-month-old infants’ expectations for what distinct count noun labels refer to were investigated. In Experiment 1, a box was opened to reveal 2 objects inside during familiarization: either 2 identical objects or 2 different objects. Test trials followed the same procedure, except before the box was opened, the contents were described using 2 distinct labels (”I see a wug! I see a dak!”) or the same label twice (”I see a zav! I see a zav!”). Infants who heard a label repeated twice looked longer at 2 different objects versus 2 identical objects, whereas infants who heard 2 distinct labels showed a different pattern of looking. Experiments 2 and 3 presented infants with object pairs that only differed in shape or color, and it was found that infants expected the different-shaped (but not the different-colored) objects to be labeled by distinct count nouns. Because the property of shape is a cue to kind membership and the property of color is not, these results suggest that even at the beginning of word learning, infants may expect distinct labels to refer to distinct kinds of objects. (PsycINFO Database Record (c) 2007 APA, all rights reserved)

A role for epigenetics in hearing: Establishment and maintenance of auditory specific gene expression patterns

from Hearing Research

Epigenetics is a large and diverse field encompassing a number of different mechanisms essential to development, DNA stability and gene expression. DNA methylation and histone modifications work individually and in conjunction with each other leading to phenotypic changes. An overwhelming amount of evidence exists demonstrating the essential nature of epigenetics to human biology and pathology. This field has spawned a vast array of knowledge, techniques and pharmaceuticals designed to investigate and manipulate epigenetic phenomena. Despite its centricity to molecular biology, little work has been conducted examining how epigenetics affects hearing. In this review, we discuss both the basic tenets of epigenetics and highlight the most recent advances in this field. We discuss its importance to human development, genomic stability, gene expression, epigenetic modifying agents as well as briefly introduce the expansive field of cancer epigenetics. We then examine the evidence of a role for epigenetics in hearing related processes and hearing loss. The article concludes with a discussion of areas of epigenetic research that could be applied to hearing research.

Effects of fast head turns on head, trunk and pelvis motions during standing and walking in patients with unilateral vestibular deficit

from the Journal of Vestibular Research

Patients with unilateral vestibular deficit (UVD) report difficulties with maintaining balance while executing fast head turns. Our aim was to determine whether head, trunk, and pelvis angular displacements were symmetrical in patients with UVD as they executed voluntary yaw rotation of the head towards or away from the side of the vestibular lesion, during standing and walking. Eight patients who underwent surgical resection of an acoustic neuroma stood with feet together or walked at comfortable pace across a 10-meter walkway. They turned the head as quickly and as fast as possible in the direction indicated by an illuminating arrow (left, right or none). The head angular displacement was similar towards the affected and intact sides. Acceleration tended to be larger during head rotations towards the affected versus the intact side by 13% at the head, 42% at the trunk and 37% at the pelvis (p> 0.05, NS). The pelvis rotated opposite to the head in 65% of trials towards the affected side and 56% of the trials towards the intact side during standing and 81% and 69%, respectively during walking. Overall, the UVD had only a minor influence on the symmetry of head, trunk and pelvis kinematics during fast yaw rotation of the head executed during standing and walking.

Vestibular evoked myogenic potential threshold and seasickness susceptibility

from the Journal of Vestibular Research

Numerous attempts have been made to find physiological parameters that might predict susceptibility to seasickness. However, to date, no physiological index has been found that can serve as a diagnostic tool for individual susceptibility to motion sickness at the personnel selection stage. A number of studies have demonstrated that linear acceleration in the vertical plane is the most provocative stimulus of motion sickness. The main physiological sensory modality responsible for monitoring vertical acceleration is the saccule. Over the last decade, vestibular evoked myogenic potentials (VEMP) have come to be recognized as a reliable procedure for the evaluation of saccular function. We used the VEMP test to assess otolith responses in 15 seasickness-susceptible (SS) and 15 non-seasickness-susceptible (NSS) healthy male crew members. The SS group exhibited a significantly higher VEMP threshold and a significantly lower peak-to-peak p13-n23 amplitude interval compared with the NSS group. Further analysis by logistic regression found threshold to be the dominant factor associated with seasickness susceptibility. The study demonstrated differences in the VEMP reflex of the SS and NSS groups. The threshold difference may represent an intrinsic mechanistic difference between the vestibular systems of the two groups. Theoretically, increased susceptibility to seasickness may be due to a discrepancy between the various neural systems as a result of reduced otolith responses.

Modification of compensatory saccades after aVOR gain recovery

from the Journal of Vestibular Research

The recruitment of extra-vestibular mechanisms to assist a deficient angular vestibulo-ocular reflex (aVOR) during ipsilesional head rotations is well established and includes saccades of reduced latency that occur in the direction of the lesioned aVOR, termed compensatory saccades (CS). Less well known is the functional relevance of these unique saccades. Here we report a 42 y.o. male diagnosed with right unilateral vestibular hypofunction due to vestibular neuronitis who underwent a vestibular rehabilitation program including gaze stabilization exercises. After three weeks, he had a significant improvement in his ability to see clearly during head rotation. Our data show a reduction in the recruitment and magnitude of CS as well as improved peripheral aVOR gain (eye velocity/head velocity) and retinal eye velocity. Our data suggest an inverse, dynamic relationship between the recruitment of CS and the gain of the aVOR.