Are deconnected cerebral hemispheres independent channels? A preliminary study of the effect of unilateral loading on bilateral finger tapping

After hemispheric deconnection, patients, whose tapping movements with one index finger at a time are nearly normal, can synchronize or alternate right and left finger tapping only at markedly decreased rates as compared to controls.

One callosectomized subject tapped with her index fingers while performing verbal tasks. Moderately difficult tasks disrupted right index tapping only; concentration on more difficult tasks and confusion arrested both index fingers.

The deconnected hemispheres have partial but not total independence. Concurrent activities maximally compete when programmed in the same hemisphere; but both hemispheres draw upon the limited and still unified attentional resources of the brain as a whole.     

Does perceived stress mediate the effect of cultural consonance on depression?

The importance of appraisal in the stress process is unquestioned. Experience in the social environment that impacts outcomes such as depression are thought to have these effects because they are appraised as a threat to the individual and overwhelm the individual's capacity to cope. In terms of the nature of social experience that is associated with depression, several recent studies have examined the impact of cultural consonance. Cultural consonance is the degree to which individuals, in their own beliefs and behaviors, approximate the prototypes for belief and behavior encoded in shared cultural models. Low cultural consonance is associated with more depressive symptoms both cross-sectionally and longitudinally. In this paper we ask the question: does perceived stress mediate the effects of cultural consonance on depression? Data are drawn from a longitudinal study of depressive symptoms in the urban community of Ribeir?o Preto, Brazil. A sample of 210 individuals was followed for 2 years. Cultural consonance was assessed in four cultural domains, using a mixed-methods research design that integrated techniques of cultural domain analysis with social survey research. Perceived stress was measured with Cohen's Perceived Stress Scale. When cultural consonance was examined separately for each domain, perceived stress partially mediated the impact of cultural consonance in family life and cultural consonance in lifestyle on depressive symptoms. When generalized cultural consonance (combining consonance in all four domains) was examined, there was no evidence of mediation. These results raise questions about how culturally salient experience rises to the level of conscious reflection.     

Musicians and non-musicians’ different reliance of features in consonance perception: A behavioral and ERP study

ObjectiveThe aim of this study was to compare the different features that musicians and non-musicians rely upon when they discern consonant and dissonant intervals. Previous studies have addressed this issue from the perspective of either the frequency ratio (Western music theory) or the frequency difference (psychoacoustics), but have not considered both features in a single and balanced study.MethodsTwelve musicians and twelve non-musicians judged musical consonance at various 50–500 Hz intervals, orthogonally selected from across the “pitch interval” and “roughness” spectrum. Both behavioral and event-related potential (ERP) data were collected separately.ResultsBehavioral results demonstrated that while musicians relied upon pitch intervals (between perfect fifths and tritones, with 95% accuracy), non-musicians performed around chance. The latter performance could, however, be sub-divided into “rough tritone and non-rough perfect-fifth” (70–80%) and “non-rough tritone and rough perfect-fifth” combinations (25–30%), suggesting non-musicians’ reliance on the roughness dimension. ERP components revealed corresponding P2 (200–250 ms) amplitude differences in the Fz and Cz channels for the “tritones vs. perfect fifths” comparison in musicians, and by the “rough vs. non-rough” comparison in the non-musicians. In addition, N1 (∼100 ms) and N2 (300–400 ms) components also revealed difference in Fz, F3, F4, FCz, Cz and CPz electrodes for “tritones vs. perfect fifths” in musicians. In the non-musicians, a stronger negative N2 for rough than for non-rough stimuli was found at F4 and Cz.ConclusionTogether, these results suggest that musicians and non-musicians rely upon pitch intervals and sensory roughness, respectively, for consonance/dissonance perception.SignificanceTo our knowledge, this is the first study to compare independently across the pitch interval and roughness spectrum. Our results further support the brain plasticity as a result of musical training in consonance perception.     

Is there a chronic change of the Mozart effect on epileptiform activity? A case study.

This report shows that a patient with the Lennox-Gastaut Syndrome had fewer clinical seizures and also fewer generalized bilateral spike and wave complexes over a 24-hour period while exposed to Mozart music (K.448) for 10 minutes every hour during wakefulness.     

Evaluation of the “monolog” spike and wave monitor: a study on patients with typical absences

The aim of this study was to evaluate the effectiveness and accuracy of the “monolog,” a pocket-size spike and wave monitor, in patients with typical absence seizures.Two observers were scoring independently and blindly from the monitor the number and duration of the 3 Hz spike-wave discharges from the EEG recordings of 10 selected patients having typical absences.High correlation was found between the two observers' scorings for both the number and the mean duration of events (Spearman's rank correlation (r): 0.9970, P < 0.001, and 0.9758, P < 0.001). Conversely, a poor correlation was found between each of the observer and the duration (r: 0.9848, P < 0.001, and 0.9788, P < 0.001). Conversely, a poor correlation was found between each of the observers and the “monolog” for the number of events (r: 0.7121, P = 0.021, and 0.6939, P = 0.026).In conclusion, the “monolog” accurately measured the duration of 3 Hz spike-wave activity; however, it failed to accurately count the number of events that occurred throughout the recordings. We suggest that this device, with appropriate modification to its memory epochs, may be a useful tool in monitoring patients with typical absences.     

Co-norming the WAIS-III and WMS-III: Is there a test-order effect on IQ and memory scores?

Test-order effect on the WAIS-III and WMS-III scores was evaluated using the WMS-III standardization sample. Participants completed the standardization editions of the WAIS-III and WMS-III in one session, with the tests administered in roughly counterbalanced order. Repeated measure MANOVA analyses were conducted to determine if there was an overall test-order effect for subtest, index, or IQ scores. No significant test-order effects were found for either the WAIS-III index or IQ scores or for the WMS-III index scores. At the subtest level, the majority of the WAIS-III and WMS-III subtests did not show a significant test-order effect. The exceptions were Digit Span and Digit Symbol-Coding on the WAIS-III and Faces II and Logical Memory II on the WMS-III. Although statistically significant test-order effects were found on these subtests, the effect sizes were small. This study indicates that the test-order effect is not a potential threat to the internal validity of the WAIS-III and WMS-III normative data. The practical implications of the current study are discussed.     

Is a plum a memory problem? Longitudinal study of the reversal of concreteness effect in a patient with semantic dementia

The concreteness effect, which refers to the typically superior performance for concrete concepts compared to abstract ones, is a robust phenomenon that has been observed in normal and brain-damaged subjects in a number of cognitive domains. Reversal of this effect was also reported in a few neuropsychological studies, mainly in patients with semantic dementia (SD). In this article, we report the first longitudinal single-case study of a patient with SD, SC, who performed better for abstract than concrete concepts in various comprehension and production tasks. For concrete concepts, SC showed no category-specific deficit but was impaired in tasks exploring access to stored structural knowledge and semantic perceptual attributes. With the course of the disease, the semantic system progressively declined and the reversal of the concreteness effect, as well as the dissociation between perceptual and non-perceptual knowledge, vanished. We discuss the results and their implications for theoretical propositions of concreteness effect as well as theoretical models of semantic memory. We suggest that the reversal of concreteness in SC is a direct result of the degradation of visual feature knowledge, sustained by anatomical structures affected early in SD. With the time course of the disease, the atrophy extends to adjacent regions and the dissociation between abstract and concrete concepts was no longer observed.     

The effect of multimorbidity on health related functioning: Temporary or persistent? Results from a longitudinal cohort study

ObjectiveMultimorbidity is known for its negative effects on health related functioning. It remains unclear if these effects are stable over time. The aim was to investigate if the relation between single morbidity/multimorbidity and health related functioning is temporary or persistent.MethodsData were collected as part of the Maastricht Aging Study (MAAS), a prospective study into the determinants of cognitive aging. Participants (n = 1184), 24–81 years old, were recruited from a patient database in primary care (Registration Network Family Practices). Morbidity status (i.e. healthy, single morbidity or multimorbidity) and the Short Form Health Survey (SF-36) were both assessed at baseline, at 3- and 6-year follow-up.ResultsAt baseline but not at 3- and 6-year follow-up, participants with single morbidity reported poorer physical functioning than their healthy counterparts. Multimorbidity was associated with poorer physical functioning at all measurements. Participants with multimorbidity showed a steep decrease in physical functioning between 3- and 6-year follow-up. Multimorbidity appeared to be unrelated to mental functioning. At baseline and at 3-year follow-up, participants who had a change in morbidity status reported poorer physical functioning than their healthy counterparts.ConclusionsPoorer physical functioning that accompanies multimorbidity is persistent and may even increase over time. People, who acquire one or more diseases during the 3-year follow-up, already showed poorer physical functioning at baseline compared to people who remained healthy during these years. Post-hoc analyses, using the SCL-90 as an outcome measure, did show that multimorbidity was related to depressive and anxiety complaints. However, these complaints seem to decline over time.     

The optic nerve: A “mito-window” on mitochondrial neurodegeneration

Retinal ganglion cells (RGCs) project their long axons, composing the optic nerve, to the brain, transmitting the visual information gathered by the retina, ultimately leading to formed vision in the visual cortex. The RGC cellular system, representing the anterior part of the visual pathway, is vulnerable to mitochondrial dysfunction and optic atrophy is a very frequent feature of mitochondrial and neurodegenerative diseases. The start of the molecular era of mitochondrial medicine, the year 1988, was marked by the identification of a maternally inherited form of optic atrophy, Leber's hereditary optic neuropathy, as the first disease due to mitochondrial DNA point mutations. The field of mitochondrial medicine has expanded enormously over the last two decades and many neurodegenerative diseases are now known to have a primary mitochondrial etiology or mitochondrial dysfunction plays a relevant role in their pathogenic mechanism. Recent technical advancements in neuro-ophthalmology, such as optical coherence tomography, prompted a still ongoing systematic re-investigation of retinal and optic nerve involvement in neurodegenerative disorders. In addition to inherited optic neuropathies, such as Leber's hereditary optic neuropathy and dominant optic atrophy, and in addition to the syndromic mitochondrial encephalomyopathies or mitochondrial neurodegenerative disorders such as some spinocerebellar ataxias or familial spastic paraparesis and other disorders, we draw attention to the involvement of the optic nerve in classic age-related neurodegenerative disorders such as Parkinson and Alzheimer disease. We here provide an overview of optic nerve pathology in these different clinical settings, and we review the possible mechanisms involved in the pathogenesis of optic atrophy. This may be a model of general value for the field of neurodegeneration. This article is part of a Special Issue entitled ‘Mitochondrial function and dysfunction in neurodegeneration’.     

The effect of anti epileptic drug therapy on serum 25-hydroxyvitamin D and parameters of calcium and bone metabolism—A longitudinal study

BackgroundChronic antiepileptic drug use is associated with bone loss. We sought to assess the longitudinal effect of antiepileptic drug on serum 25-hydroxyvitamin D [25(OH)D] levels and bone mineral metabolism markers.MethodsPatients in the emergency services or those in neurology outpatient department with history of seizure were characterized and included in the study prospectively. Daily dietary intake of calories, calcium, phosphorus and phytates were characterized by dietary recall method. Base line bone mineral parameters – serum calcium, phosphorus, alkaline phosphatase (SAP), tartrate resistant acid phosphatase (TRACP), 25(OH)D levels, parathyroid hormone (PTH) and urinary calcium creatinine ratio (Ca.Cr), urinary calcium/kg/bodyweight (BW) and phosphate excretion index (PEI) were determined. Patients on AED therapy with normal 25(OH)D levels were followed up and were re-evaluated at the end of 6 months.ResultsThe daily dietary calcium intake of the subjects was lower than the RDA (Recommended Dietary Allowance) by ICMR (Indian Council of Medical Research). The diet was high in phytates. Two-thirds of the recruited subjects were vitamin D deficient. Subjects with normal 25(OH)D levels at base line showed a significant fall of 25(OH)D levels, urinary calcium, urinary calcium/kg/BW and TRACP levels at the end of 6 months irrespective of the AED used or the plasma level of AED.ConclusionsHypovitaminosis D is common in our population. Subjects with normal 25(OH)D levels, irrespective of the type of antiepileptic medications even at sub-therapeutic serum levels of the drug, went into 25(OH)D deficiency and insufficiency states. Theoretically it can be worthwhile to supplement calcium and vitamin D even before initiation of antiepileptic therapy.     

The influence of levetiracetam on psychosocial and behavioral functioning in children: A case–control and follow-up study

BackgroundLevetiracetam, a widely used antiepileptic drug in children, has been associated with psychosocial and behavioral problems, which are also influenced by epilepsy variables, including duration or seizure frequency.PurposeThe objective of this study is to investigate the frequency and timing of treatment-emergent psychosocial and behavioral problems in children receiving levetiracetam, irrespective of seizure variables which are possible confounders.MethodsA prospective, case–control study with a 3-month follow-up was conducted. Consecutive children aged 6 to 16 years with new-onset partial seizures were included in case of starting treatment with either levetiracetam or valproic acid. Psychosocial and behavioral functioning were assessed using a set of standardized questionnaires including Strengths and Difficulties Questionnaire (SDQ) and Children's Depression Inventory (CDI) at baseline, 1 and 3-month follow-up. Patients' baseline scores were compared to healthy subjects. The difference in the follow-up SDQ and CDI scores was evaluated in patients receiving levetiracetam and valproic acid.ResultsA total of 101 participants were analyzed; 32 patients in levetiracetam group, 19 patients in valproic acid group and 50 healthy controls. Baseline SDQ and CDI scores were not statistically different between patients and healthy subjects (p > 0.05). No statistically significant difference was observed in CDI, total and subscale SDQ scores between patients receiving levetiracetam or valproic acid during the study period (p > 0.05). A girl aged 15 years receiving levetiracetam had a CDI score of 18 without suicidal ideation at baseline. She developed suicidal ideation and depression, which resolved after switching of levetiracetam to valproic acid, at the 1-month follow-up. No other psychiatric or behavioral side-effects were observed in other patients.ConclusionPsychosocial and behavioral side-effects of levetiracetam treatment are not frequent and they don't emerge in most of children at lower doses. At this dose, and after 3 months, using these specific instruments, we did not observe any difference between the valproic acid and levetiracetam treatment groups.     

The effect of oxytocin on cooperation in a prisoner’s dilemma depends on the social context and a person’s social value orientation

The interactionist approach to the study of exogenous oxytocin (OT) effects on prosocial behavior has emphasized the need to consider both contextual cues and individual differences. Therefore, an experiment was set up to examine the joint effect of intranasal OT, a salient social cue and the personality trait social value orientation on cooperative behavior in one-shot prisoner’s dilemma games. The outcome of these mixed-motive games is known to be highly dependent on values and on social information that might reveal the partner’s intent. Consistent with an a priori hypothesis, OT and social information interact significantly to affect the behavior of individuals with a proself value orientation: after prior contact with the game partner, OT enhances cooperative behavior, whereas in anonymous conditions, it exacerbates their intrinsic self-interested behavior. These effects of OT do not hold for individuals with a prosocial value orientation, whose cooperation levels appear to be more influenced by prior contact with the game partner. Follow-up hypotheses for why prosocial and proself individuals respond differently to exogenous OT were developed.     

Moonstruck? The effect of the lunar cycle on seizures

Recent reports on the effects of the lunar cycle on seizure occurrence have yielded mixed results. If the moon phase is influential, we hypothesized that this would be due to the moon's contribution to nocturnal illumination, rather than its waxing or waning state, and that significant correlations would not be apparent if local cloud cover were controlled for. We found a significant negative correlation between the mean number of seizures and the fraction of the moon illuminated by the sun (rho=-0.09, P<0.05) in 1571 seizures recorded in a dedicated epilepsy inpatient unit over 341 days. This correlation disappeared when we controlled for the local clarity of the night sky, suggesting that it is the brightness of the night and the contribution the moon phase makes to nocturnal luminance, rather than the moon phase per se, that may influence the occurrence of epileptic seizures.