From Motivation to Action: Action Cost Better Predicts Changes in Premovement Beta-Band Activity than Speed.

Although premovement beta-band event-related desynchronization (ß-ERD; 13-30 Hz) from sensorimotor regions is modulated by movement speed, current evidence does not support a strict monotonic association between the two. Given that ß-ERD is thought to increase information encoding capacity, we tested the hypothesis that it might be related to the expected neurocomputational cost of movement, here referred to as action cost. Critically, action cost is greater both for slow and fast movements compared with a medium or "preferred" speed. Thirty-one right-handed participants performed a speed-controlled reaching task while recording their EEG. Results revealed potent modulations of beta power as a function of speed, with ß-ERD being significantly greater both for movements performed at high and low speeds compared with medium speed. Interestingly, medium-speed movements were more often chosen by participants than low-speed and high-speed movements, suggesting that they were evaluated as less costly. In line with this, modeling of action cost revealed a pattern of modulation across speed conditions that strikingly resembled the one found for ß-ERD. Indeed, linear mixed models showed that estimated action cost predicted variations of ß-ERD significantly better than speed. This relationship with action cost was specific to beta power, as it was not found when averaging activity in the mu band (8-12 Hz) and gamma band (31-49 Hz) bands. These results demonstrate that increasing ß-ERD may not merely speed up movements, but instead facilitate the preparation of high-speed and low-speed movements through the allocation of additional neural resources, thereby enabling flexible motor control.SIGNIFICANCE STATEMENT Heightened beta activity has been associated with movement slowing in Parkinson's disease, and modulations of beta activity are commonly used to decode movement parameters in brain-computer interfaces. Here we show that premovement beta activity is better explained by the neurocomputational cost of the action rather than its speed. Instead of being interpreted as a mere reflection of changes in movement speed, premovement changes in beta activity might therefore be used to infer the amount of neural resources that are allocated for motor planning.

The activity of 210Pb in cigarette smoked in Kazakhstan.

The radon decay product 210Pb is a known component of tobacco. In this study, the activity concentration of 210Pb in the most popular cigarette brands (six samples) for Kazakhstan consumers was determined by beta spectrometry. The activity levels of 210Pb ranged between 2.69 ± 0.27 and 27.42 ± 2.74 mBq per cigarette. Higher activity concentrations for 210Pb were found in Sample No.4 and showed an excess of the world average by 1.8 times. The average activity concentrations of 210Pb in cigarette tobacco were 10.42 ± 1.04 mBq cig-1. The daily activities inhaled in the lungs of a smoker, and the resulting effective doses due to cigarette smoking were calculated. Effective doses per year due to cigarette smoking were calculated assuming that 42.13% of the 210Pb in tobacco were retained in the lungs of the smokers. It is concluded that for a smoker in Kazakhstan, the average effective dose ranges from 9.1 ± 0.9 µSv/year to 92.8 ± 9.3 µSv/year for a cigarette consumption of one pack of cigarettes per day. The results indicate that the annual effective doses from inhalation of 210Pb due to smoking one pack of cigarettes per day are from 7 to 58 times (for different types of cigarettes) greater than the annual effective doses from ingestion of radionuclides via the diet.

Assessment of physicochemical properties and radioactivity in groundwater at households living in bac Lieu province, vietnam.

This paper presents findings on groundwater physiochemical composition and radioactivity levels in households in Bac Lieu province, Vietnam. Through discriminant analysis, it was observed that groundwater quality exhibits spatial variations corresponding to saline intrusion zones. The paired-samples T-tests revealed significantly different ratios of Ra-224, Ra-226, and Ra-228 isotopes between Na-Cl and Ca-Na-HCO3 water types. All three water types had a ratio of Ra-226/Ra-228 of approximately one, indicating the presence of groundwater aquifers beneath the crust and fluvial marine sediment. Furthermore, strong associations between sulfate and calcium suggest that CO2 enrichment in groundwater aquifers indicates anoxic aquatic environments. Twenty-five of the thirty-three evaluated samples exceeded the national technical regulations for domestic water quality with parameters such as chloride, sulfate, sodium, gross alpha, or total dissolved solids. Fifteen samples exceeded gross alpha's allowable contamination threshold of 0.1 Bq/L. The combination of Ra-226 and Ra-228 did not surpass the U.S. Environmental Protection Agency's recommended limit of 0.185 Bq/L. However, nineteen samples exhibited annual committed effective doses of radium isotopes for infants that exceeded the WHO recommendation of 0.1 mSv/year.

Spectral brain signatures of aesthetic natural perception in the α and ß frequency bands.

During our everyday lives, visual beauty is often conveyed by sustained and dynamic visual stimulation, such as when we walk through an enchanting forest or watch our pets playing. Here, I devised an MEG experiment that mimics such situations: participants viewed 8 s videos of everyday situations and rated their beauty. Using multivariate analysis, I linked aesthetic ratings to 1) sustained MEG broadband responses and 2) spectral MEG responses in the α and ß frequency bands. These effects were not accounted for by a set of high- and low-level visual descriptors of the videos, suggesting that they are genuinely related to aesthetic perception. My findings provide the first characterization of spectral brain signatures linked to aesthetic experiences in the real world.NEW & NOTEWORTHY In the real world, aesthetic experiences arise from complex and dynamic inputs. This study shows that such aesthetic experiences are represented in a spectral neural code: cortical α and ß activity track our judgments of the aesthetic appearance of natural videos, providing a new starting point for studying the neural correlates of beauty through rhythmic brain activity.

Muscarinic and N-methyl-D-aspartate receptor blockade reveal differences in hippocampal local field potentials in mice with low cholinergic tone.

We hypothesize that hippocampal local field potentials in acetylcholine (ACh)-deficient mutant mice, compared to wild-type (WT) mice, will show lower sensitivity to muscarinic cholinergic antagonist scopolamine (5 mg/kg i.p.) but higher sensitivity to NMDA receptor antagonist 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP, 10 mg/kg i.p.). Recordings were made during walk and awake-immobility (IMM) in WT mice, and in mice with forebrain knockout (KO) of the vesicular acetylcholine transporter (VAChT) gene, or heterozygous knockdown of VAChT gene (KD). Scopolamine or CPP did not significantly alter walk theta frequency, which was higher in KD than WT/KO mice. Scopolamine decreased theta power peak rise during walk in WT/KD mice but not in KO mice, while CPP suppressed theta peak rise more in WT/KO mice than KD mice. During IMM, scopolamine decreased gamma1 (γ1, 30-58 Hz) power more in KD/WT mice than KO mice, while delta (1-4 Hz) power and delta-gamma cross-frequency coherence (CFC) were increased in all mouse groups during IMM or walk. During walk, scopolamine increased delta and beta (13-30 Hz) power and decreased gamma2 (γ2, 62-100 Hz) power and theta-γ2 CFC more in WT/KD than KO mice. Theta-γ2, but not theta-γ1, CFC increased with theta-peak-frequency in WT/KD mice, and was suppressed by scopolamine at high theta (8-10 Hz) frequency; theta-γ2 CFC in KO mice was not significantly altered by scopolamine. CPP decreased beta and gamma power more in KD/KO mice compared to WT mice, while delta power and delta-gamma CFC were increased in all mouse groups. ACh deficiency exacerbates the attenuation of beta and gamma power by CPP. We conclude that both muscarinic and NMDA transmission contribute toward hippocampal theta, beta, and gamma power, and a decrease in gamma power or theta-gamma CFC may be associated with loss of arousal and cognitive functions.

Separating EEG correlates of stress: Cognitive effort, time pressure, and social-evaluative threat.

The prefrontal cortex is a key player in stress response regulation. Electroencephalographic (EEG) responses, such as a decrease in frontal alpha and an increase in frontal beta power, have been proposed to reflect stress-related brain activity. However, the stress response is likely composed of different parts such as cognitive effort, time pressure, and social-evaluative threat, which have not been distinguished in previous studies. This distinction, however, is crucial if we aim to establish reliable tools for early detection of stress-related conditions and monitoring of stress responses throughout treatment. This randomized cross-over study (N = 38) aimed to disentangle EEG correlates of stress. With linear mixed models accounting for missing values in some conditions, we found a decrease in frontal alpha and increase in beta power when performing the Paced Auditory Serial Addition Test (PASAT; cognitive effort; n = 32) compared to resting state (n = 33). No change in EEG power was found when the PASAT was performed under time pressure (n = 29) or when adding social-evaluative threat (video camera; n = 29). These findings suggest that frontal EEG power can discriminate stress from resting state but not more fine-grained differences of the stress response.

Double antiglutamatergic treatment in patients with status epilepticus: A case series.

INTRODUCTION: Status epilepticus (SE) continues to be a challenging neurological emergency with high morbidity and mortality. During treatment, different regimens are practiced encompassing all known seizure termination mechanisms. To our knowledge, this is the first case series report describing EEG patterns and clinical outcomes in patients treated with ketamine and perampanel (PER) concomitantly. OBJECTIVE: To assess clinical and electrographic outcomes in patients receiving dual antiglutamatergic therapy in SE. RESULTS: Twenty-one out of twenty five patients were treated with ketamine, and four patients with ketamine were associated with PER. In the ketamine plus PER group, three out of four patients had convulsive SE, and one had non-convulsive status epilepticus (NCSE), whereas eight patients in the ketamine group had NCSE. The incidence of beta pattern appearance on EEG after starting patients on ketamine and PER was achieved in all four patients (100%) compared to (61.9%) in the other group. A burst suppression pattern was recorded in 75% of patients treated with ketamine and PER, in comparison to 28.5% of patients in patients treated with a different regimen. The time to resolution of SE was significantly shorter in the ketamine group (median 24 (24-64) h vs. 6 (05-144) h p > 0.05). Moreover, the average number of days on IV anesthetic was slightly lower in a patient treated with PER concomitantly. In terms of morbidity, the average increase in mRS was also lower in the ketamine and PER group, although it was not statistically significant. CONCLUSIONS: Dual anti-glutamatergic therapy could provide a favorable approach to treating SE, which yet needs to be further investigated through larger randomized control studies.

The role of ketamine-induced beta activity in the treatment of refractory status epilepticus. Is the EEG useful to determine responder's rate? A retrospective study.

INTRODUCTION: Multiple investigations have been done to evaluate the possible effect of ketamine in the treatment of status epilepticus (SE). OBJECTIVES: To evaluate the electrographic effect of ketamine on EEG, and its clinical utility following-up refractory and super refractory status epilepticus (SRSE). METHODS: Retrospective review of 24 patients with SE. Clinical record and Video-electroencephalogram (video-EEG) of all included patients were reviewed. The patients' EEGs were then monitored for any immediate changes after administration of the first dose of ketamine as well as at the time patients would be predicted to have peak serum concentration of ketamine. Patients with cessation of electrographic seizures and no SE recurrence within the same admissions were categorized as "Responders". Statistical differences between qualitative variables were analyzed using chi square test. Differences between median were analyzed by Mann-Whitney U test. Difference between groups were considered significant when p < 0.05. RESULTS: We identified 24 patients with SE. Twelve out of 24 (50%) had SRSE and 12 out of 24 (50%) had refractory status epilepticus (RSE). The appearance of superimposed beta activity after ketamine was initiated was associated with a higher responder rate (100% versus 33.3% in the responder group versus the non-responder group respectively). Notably, the presence of a burst suppression pattern had no significant association with one group compared to the other (41.6% versus 33.3%, in the responder group vs the non-responder group respectively). CONCLUSIONS: Background superimposed beta activity induced by ketamine is an early and reliable EEG finding associated with status epilepticus termination.

Correlation between cortical beta power and gait speed is suppressed in a parkinsonian model, but restored by therapeutic deep brain stimulation.

The motor cortex and subthalamic nucleus (STN) of patients with Parkinson's disease (PD) exhibit abnormally high levels of electrophysiological oscillations in the ~12-35 Hz beta-frequency range. Recent studies have shown that beta is partly carried forward to regulate future motor states in the healthy condition, suggesting that steady state beta power is lower when a sequence of movements occurs in a short period of time, such as during fast gait. However, whether this relationship between beta power and motor states persists upon parkinsonian onset or in response to effective therapy is unclear. Using a 6-hydroxy dopamine (6-OHDA) rat model of PD and a custom-built behavioral and neurophysiological recording system, we aimed to elucidate a better understanding of the mechanisms underlying cortical beta power and PD symptoms. In addition to elevated levels of beta oscillations, we show that parkinsonian onset was accompanied by a decoupling of movement intensity - quantified as gait speed - from cortical beta power. Although subthalamic deep brain stimulation (DBS) reduced general levels of beta oscillations in the cortex of all PD animals, the brain's capacity to regulate steady state levels of beta power as a function of movement intensity was only restored in animals with therapeutic DBS. We propose that, in addition to lowering general levels of cortical beta power, restoring the brain's ability to maintain this inverse relationship is critical for effective symptom suppression.

Scalp EEG Ictal gamma and beta activity during infantile spasms: Evidence of focality.

OBJECTIVE: We investigated temporal and spatial characteristics of ictal gamma and beta activity on scalp EEG during spasms in patients with West syndrome (WS) to evaluate potential focal cortical onset. METHODS: A total of 1,033 spasms from 34 patients with WS of various etiologies were analyzed on video-electroencephalography (EEG) using time-frequency analysis. Ictal gamma (35-90 Hz) and beta (15-30 Hz) activities were correlated with visual symmetry of spasms, objective EMG (electromyography) analysis, and etiology of WS. RESULTS: Prior to the ictal motor manifestation, focal ictal gamma activity emerged from one hemisphere (71%, 24/34) or from midline (26%, 9/34), and was rarely simultaneously bilateral (3%, 1/34). Focal ictal beta activity emerged from either one hemisphere (68%, 23/34) or from midline (32%, 11/34). Onsets of focal ictal gamma and beta activity were most commonly observed around the parietal areas. Focal ictal gamma activity propagated faster than ictal beta activity to adjacent electrodes (median: 65 vs. 170 msec, p < 0.01), and to contralateral hemisphere (median: 100 vs. 170 msec, p = 0.01). Asymmetric peak amplitude of ictal gamma activity in the centroparietal areas (C3-P3 vs. C4-P4) correlated with asymmetric semiology. On the other hand, most of the visually symmetric spasms showed asymmetry in peak amplitude and interhemispheric onset latency difference in both ictal gamma and beta activity. SIGNIFICANCE: Spasms may be a seizure with focal electrographic onset regardless of visual symmetry. Asymmetric involvement of ictal gamma activity to the centroparietal areas may determine the motor manifestations in WS. Scalp EEG ictal gamma and beta activity may be useful to demonstrate localized seizure onset in infants with WS.

High beta activity in the subthalamic nucleus and freezing of gait in Parkinson's disease.

OBJECTIVE: Oscillatory activity in the beta band is increased in the subthalamic nucleus (STN) of Parkinson's disease (PD) patients. Rigidity and bradykinesia are associated with the low-beta component (13-20Hz) but the neurophysiological correlate of freezing of gait in PD has not been ascertained. METHODS: We evaluated the power and coherence of the low- and high-beta bands in the STN and cortex (EEG) of PD patients with (p-FOG) (n=14) or without freezing of gait (n-FOG) (n=8) in whom electrodes for chronic stimulation in the STN had been implanted for treatment with deep brain stimulation. RESULTS: p-FOG patients showed higher power in the high-beta band (F=11.6, p=0.002) that was significantly reduced after l-dopa administration along with suppression of FOG (F=4.6, p=0.042). High-beta cortico-STN coherence was maximal for midline cortical EEG electrodes, whereas the low-beta band was maximal for lateral electrodes (χ(2)=20.60, p<0.0001). CONCLUSIONS: The association between freezing of gait, high-beta STN oscillations and cortico-STN coherence suggests that this oscillatory activity might interfere in the frontal cortex-basal ganglia networks, thereby participating in the pathophysiology of FOG in PD.

The highs and lows of beta activity in cortico-basal ganglia loops.

Oscillatory activity in the beta (13-30 Hz) frequency band is widespread in cortico-basal ganglia circuits, and becomes prominent in Parkinson's disease (PD). Here we develop the hypothesis that the degree of synchronization in this frequency band is a critical factor in gating computation across a population of neurons, with increases in beta band synchrony entailing a loss of information-coding space and hence computational capacity. Task and context drive this dynamic gating, so that for each state there will be an optimal level of network synchrony, and levels lower or higher than this will impair behavioural performance. Thus, both the pathological exaggeration of synchrony, as observed in PD, and the ability of interventions like deep brain stimulation (DBS) to excessively suppress synchrony can potentially lead to impairments in behavioural performance. Indeed, under physiological conditions, the manipulation of computational capacity by beta activity may itself present a mechanism of action selection and maintenance.

Human health risk assessment due to consumption of dried fish in Chennai, Tamil Nadu, India: a baseline report.

The current study sought to determine the levels of radioactivity and heavy metal contamination in 22 dried fish samples collected in Chennai, Tamil Nadu. The study found that there were substantial heavy metals concentrations for Pb, Mn, Cr, Co, and Cd. The concentration of heavy metal Pb being alarmingly high (32.85 to 42.09 mg/kg), followed by Cd (2.18 mg/kg to 3.51 mg/kg) than the permissible limit of WHO (2.17 mg/kg) for Pb and (0.05 mg/kg) for Cd. In terms of radioactivity, the gross alpha activity in the dried fish samples ranged 6.25 ± 0.12 to 48.21 ± 0.11 Bg/kg with an average of 20.35 Bg/kg and with a gross beta activity from 6.48 ± 0.02 to 479.47 ± 0.65 Bg/kg, for an average of 136.83 Bg/kg. The study found that the internal radiation dose that people receive upon consuming the fish species Sphyraena obtusata, Rachycentron canadum, Lepidocephalichthys thermalis, Synodontidae, Carangoides malabaricus, Sardina pilchardus, Scomberomorus commerson, Sillago sihama, Gerres subfasciatus, and Amblypharyngodon mola is above the ICRP-recommended limit of less than 1 mSv/year. Annual gonadal dose equivalent (AGDE) and total excessive lifetime cancer risk (ELCR) ranged 0.488 µSv year-1 and 0.004 µSv year-1 respectively, the values of AGDE being higher than the global average value. The findings of the study indicate that the analyzed dried fish samples are contaminated with Pb and Cd, which shall pose cancer risk to the consumers as a result.

A probabilistic approach to the estimation of radioactive contaminant inventories at a nuclear waste disposal site.

Routine site inspections are often conducted to gather data on radiation contamination on the surface and below ground near nuclear waste disposal areas. These observations are used to calculate total radiation inventory and its spatial delineation. The statistical kriging approach is often used to spatially interpolate contamination data, and it generates predictions at unsampled sites that are then utilized to calculate the contaminated site's radiation inventory. The kriging output, however, creates a point estimate of the inventory that omits the potential uncertainties from other sources. This paper presents a method for assessing the uncertainty of radiation inventories based on the geostatistical conditional simulation method - a simulation methodology that takes into account the observations made at the sampled sites. The radiation inventories' histograms are generated by conducting many conditional simulations of the projection map using a fitted kriging model. A practical implementation of the suggested approach is shown by evaluating total beta inventories and their spatial delineation using groundwater monitoring data at a nuclear waste disposal site.

Distribution of Natural Radionuclides and 137Cs in Urban Soil Samples from the City of Novi Sad, Serbia-Radiological Risk Assessment.

This work presents the natural radioactivity distribution of 21 surface soil samples taken in the city of Novi Sad, Serbia. The analysis for radioactivity was performed using a gas low-level proportional counter for gross alpha and gross beta activity, while the specific activities of radionuclides were determined using HPGe detectors. The gross alpha activity of 20 samples was below the minimum detectable concentration (MDC), while in 1 sample it was 243 Bq kg-1; the gross beta activity ranged from the MDC (11 samples) to 566 Bq kg-1. The gamma spectrometry measurements showed naturally occurring radionuclides 226Ra, 232Th, 40K, and 238U in all investigated samples, with average values (Bq kg-1) of 33.9, 36.7, 513.8, and 34.7, respectively. Natural radionuclide 235U was detected in 18 samples with activity concentrations in the range of 1.3-4.1 Bq kg-1, while in the other 3 samples, the values were below the MDC. The artificial 137Cs radionuclide was detected in 90 percent of the samples, with a maximum value of 21 Bq kg-1, while the other artificial radionuclides were not detected. Based on the obtained concentrations of natural radionuclides, hazard indexes were estimated, and radiological health risk was assessed. The results present the absorbed gamma dose rate in the air, annual effective dose, radium equivalent activity, external hazard index, and lifetime cancer risk.

Spectral and spatial distribution of subthalamic beta peak activity in Parkinson's disease patients.

Current efforts to optimise subthalamic deep brain stimulation in Parkinson's disease patients aim to harness local oscillatory activity in the beta frequency range (13-35 Hz) as a feedback-signal for demand-based adaptive stimulation paradigms. A high prevalence of beta peak activity is prerequisite for this approach to become routine clinical practice. In a large dataset of postoperative rest recordings from 106 patients we quantified occurrence and identified determinants of spectral peaks in the alpha, low and high beta bands. At least one peak in beta band occurred in 92% of patients and 84% of hemispheres off medication, irrespective of demographic parameters, clinical subtype or motor symptom severity. Distance to previously described clinical sweet spot was significantly related both to beta peak occurrence and to spectral power (rho -0.21, p 0.006), particularly in the high beta band. Electrophysiological landscapes of our cohort's dataset in normalised space showed divergent heatmaps for alpha and beta but found similar regions for low and high beta frequency bands. We discuss potential ramifications for clinicians' programming decisions. In summary, this report provides robust evidence that spectral peaks in beta frequency range can be detected in the vast majority of Parkinsonian subthalamic nuclei, increasing confidence in the broad applicability of beta-guided deep brain stimulation.

Performance evaluation of a European wide proficiency test on gross alpha/beta activity determination in drinking water.

JRC-Geel organised a Europe-wide proficiency test on gross alpha/beta activity concentration measurements in water with 154 participants from the field of environmental radioactivity monitoring. The performance of the participants was evaluated by comparing their results to the reference value using percentage deviation, z-score and zeta-score. Many of the participants' results deviated several orders of magnitude from the reference values regardless of the techniques used suggesting that the radioactivity monitoring of drinking water using gross-counting in Europe needs improving. Comparing with a similar proficiency test in 2012 reveals no major improvements and indicate that standards for gross-counting methods need revision. From the accompanied questionnaire, participants' measurement methods, laboratory practices and pitfalls were discussed. From the 14 best performing methods, JRC identified "Best practices".

Parkinson's disease is characterized by sub-second resting-state spatio-oscillatory patterns: A contribution from deep convolutional neural network.

Deep convolutional neural network (DCNN) provides a multivariate framework to detect relevant spatio-oscillatory patterns in the data beyond common mass-univariate statistics. Yet, its practical application is limited due to the low interpretability of the results beyond accuracy. We opted to use DCNN with a minimalistic architecture design and large penalized terms to yield a generalizable and clinically relevant network model. Our network was trained based on the scalp topology of the electroencephalography (EEG) from an open access dataset, constituting our primary sample of healthy controls (n = 25) and Parkinson's disease (PD) patients (n = 25), with and without medication. Next, we validated the model on another independent, yet comparable open access EEG dataset (healthy controls (n = 20) and PD patients (n = 20)), which was unseen to the network. We applied Gradient-weighted Class Activation Mapping (Grad-CAM) interpretability technique to create a localization map exhibiting the key network predictors, based on the gradients of the classification score flowing into the last convolutional layer. Accordingly, our results indicated that a sub-second of intrinsic oscillatory power pattern in the beta band over the occipitoparietal, gamma band over the left motor cortex as well as theta band over the frontoparietal cluster, had the largest impact on the network score for dissociating the PD patients from age- and gender-matched healthy controls, across the two datasets. We further found that the off-medication motor symptoms were related to the occipitoparietal off-medication beta power whereas the disease duration was associated with the off-medication beta power of the motor cortex. The on-medication theta power of the frontoparietal was related to the improvement of the motor symptoms. In conclusion, our method enabled us to characterize PD patho-electrophysiology according to the multivariate topographic analysis approach, where both spatial and frequency aspects of the oscillations were simultaneously considered. Moreover, our approach was free from common reference problem of the EEG data analyses.

Measurement of age-dependent radiation ingestion doses due to gross alpha and gross beta exposure from medicinal plants.

This article presents the results of a study conducted to measure the gross alpha, gross beta activities in medicinal plant samples collected from different districts of Azad Kashmir, Pakistan. The ASC-950-DP gasless high-speed counter was used for the measurement of gross α/ß activities. Measured activities have been used to assess age-dependent annual effective doses for infants, one-, five-, ten-, and fifteen-year-old and adult people. For a medicinal plant consumption rate (MPCR) of 1.8 kg a-1, the average gross alpha and beta annual committed effective dose (ACED) delivered to one-, five-, ten-, fifteen-year-olds and adults fall below the WHO recommended level (290 µSv a-1) and that reported in the UNSCEAR 2000 (0.3 mSv a-1) report. Results obtained for the current study show that the radiological hazard related to the consumption of natural radionuclides in medicinal plants is inconsequential with exception of the ACED delivered to infants at an MPCR of 1.8 g a-1 and higher values.

Neurological toxicity due to antimonial treatment for refractory visceral leishmaniasis.

INTRODUCTION: Although pentavalent antimonials are no longer considered the first-line therapy for visceral leishmaniasis in the developed world, they are still used in certain geographical areas and in refractory cases. These drugs have a great number of adverse effects; however, neurological toxicity has been rarely reported. CASE REPORT: We present a 56-year-old woman who required long-term treatment with antimonial drugs due to refractory visceral leishmaniasis and presented clinically with tremor of extremities, myoclonus, gait disturbances and epileptic seizures. The EEG showed increased beta rhythms and generalized epileptogenic activity. She had a slow but favorable response after the withdrawal of antimonials and the initiation of anticonvulsant therapy. CONCLUSION: Severe but reversible neurological toxicity is a rare adverse effect of prolonged antimonial treatment. More EEG record data are needed to support the suspicion of a possible increase of beta rhythms in this situation.