Absence Seizures as a Feature of Juvenile Myoclonic Epilepsy in Rhodesian Ridgeback Dogs.

Myoclonic epilepsy in Rhodesian Ridgeback (RR) dogs is characterized by myoclonic seizures occurring mainly during relaxation periods, a juvenile age of onset and generalized tonic-clonic seizures in one-third of patients. An 8-month-old female intact RR was presented for myoclonic seizures and staring episodes that both started at 10 weeks of age. Testing for the DIRAS1 variant indicated a homozygous mutant genotype. Unsedated wireless video-electroencephalography (EEG) identified frequent, bilaterally synchronous, generalized 4 Hz spike-and-wave complexes (SWC) during the staring episodes in addition to the characteristic myoclonic seizures with generalized 4-5 Hz SWC or 4-5 Hz slowing. Photic stimulation did not evoke a photoparoxysmal response. Repeat video-EEG 2 months after initiation of levetiracetam treatment disclosed a >95% decrease in frequency of myoclonic seizures, and absence seizures were no longer evident. Absence seizures represent another seizure type in juvenile myoclonic epilepsy (JME) in RR dogs, which reinforces its parallels to JME in humans.

Diagnostic Utility of Wireless Video-Electroencephalography in Unsedated Dogs.

BACKGROUND: Poor agreement between observers on whether an unusual event is a seizure drives the need for a specific diagnostic tool provided by video-electroencephalography (video-EEG) in human pediatric epileptology. OBJECTIVE: That successful classification of events would be positively associated with increasing EEG recording length and higher event frequency reported before video-EEG evaluation; that a novel wireless video-EEG technique would clarify whether unusual behavioral events were seizures in unsedated dogs. ANIMALS: Eighty-one client-owned dogs of various breeds undergoing investigation of unusual behavioral events at 4 institutions. METHODS: Retrospective case series: evaluation of wireless video-EEG recordings in unsedated dogs performed at 4 institutions. RESULTS: Electroencephalography achieved/excluded diagnosis of epilepsy in 58 dogs (72%); 25 dogs confirmed with epileptic seizures based on ictal/interictal epileptiform discharges, and 33 dogs with no EEG abnormalities associated with their target events. As reported frequency of the target events decreased (annually, monthly, weekly, daily, hourly, minutes, seconds), EEG was less likely to achieve diagnosis (P < 0.001). Every increase in event frequency increased the odds of achieving diagnosis by 2.315 (95% confidence interval: 1.36-4.34). EEG recording length (mean = 3.69 hours, range: 0.17-22.5) was not associated (P = 0.2) with the likelihood of achieving a diagnosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Wireless video-EEG in unsedated dogs had a high success for diagnosis of unusual behavioral events. This technique offered a reliable clinical tool to investigate the epileptic origin of behavioral events in dogs.

Systemic availability of guanidinoacetate affects GABAA receptor function and seizure threshold in GAMT deficient mice.

Deficiency of guanidinoacetate methyltransferase (GAMT) causes creatine depletion and guanidinoacetate accumulation in brain with the latter deemed to be responsible for the severe seizure disorder seen in affected patients. We studied electrical brain activity and GABAA mediated mechanisms of B6J.Cg-Gamt(tm1Isb) mice. Electrocorticographic (ECoG) monitoring of pharmacological treatments with ornithine (5 % in drinking water for 5-18 days) and/or Picrotoxin (PTX) (a GABAA receptor antagonist) (1.5 mg/kg, I.P.) in Gamt(MUT) and Gamt(WT) groups [n = 3, mean age (SEM) = 6.9 (0.2) weeks]. Mice were fitted with two frontal and two parietal epidural electrodes under ketamine/xylazine anesthesia. Baseline and test recordings were performed for determination of seizure activity over a 2 h period. The ECoG baseline of Gamt(MUT) exhibited an abnormal monotonous cortical rhythm (7-8 Hz) with little variability during awake and sleep states compared to wild type recordings. Ornithine treatment and also PTX administration led to a relative normalization of the Gamt(MUT) ECoG phenotype. Gamt(WT) on PTX exhibited electro-behavioral seizures, whereas the Gamt(MUT) did not have PTX induced seizures at the same PTX dose. Gamt(MUT) treated with both ornithine and PTX did not show electro-behavioral seizures while ornithine elevated the PTX seizure threshold of Gamt(MUT) mice even further. These data demonstrate: (1) that there is expression of electrical seizure activity in this Gamt-deficient transgenic mouse strain, and (2) that the systemic availability of guanidinoacetate affects GABAA receptor function and seizure thresholds. These findings are directly and clinically relevant for patients with a creatine-deficiency syndrome due to genetic defects in GAMT and provide a rational basis for a combined ornithine/picrotoxin therapeutic intervention.

HINCUTs in cancer: hypoxia-induced noncoding ultraconserved transcripts.

Recent data have linked hypoxia, a classic feature of the tumor microenvironment, to the function of specific microRNAs (miRNAs); however, whether hypoxia affects other types of noncoding transcripts is currently unknown. Starting from a genome-wide expression profiling, we demonstrate for the first time a functional link between oxygen deprivation and the modulation of long noncoding transcripts from ultraconserved regions, termed transcribed-ultraconserved regions (T-UCRs). Interestingly, several hypoxia-upregulated T-UCRs, henceforth named 'hypoxia-induced noncoding ultraconserved transcripts' (HINCUTs), are also overexpressed in clinical samples from colon cancer patients. We show that these T-UCRs are predominantly nuclear and that the hypoxia-inducible factor (HIF) is at least partly responsible for the induction of several members of this group. One specific HINCUT, uc.475 (or HINCUT-1) is part of a retained intron of the host protein-coding gene, O-linked N-acetylglucosamine transferase, which is overexpressed in epithelial cancer types. Consistent with the hypothesis that T-UCRs have important function in tumor formation, HINCUT-1 supports cell proliferation specifically under hypoxic conditions and may be critical for optimal O-GlcNAcylation of proteins when oxygen tension is limiting. Our data gives a first glimpse of a novel functional hypoxic network comprising protein-coding transcripts and noncoding RNAs (ncRNAs) from the T-UCRs category.

Effect of calcium addition and pH on yield and texture of Minas cured cheese / Efeito da adição de cálcio e do pH sobre o rendimento e a textura de queijo-de-Minas curado

Milk calcium concentration is a factor related to cheese texture, an important rheological property of cheese quality as perceived by consumers. This study aimed to evaluate the effect of different pH conditions (5.8 and 6.6) and calcium addition (0, 150, 300 ppm of CaCl2), on yield and nutrient retention of the clots obtained and on the texture of Minascured cheese. Clots were analyzed for wet and dry yield, percentage content and retention of protein, fat and calcium. The texture of the cheese was evaluated by instrumental and sensorial tests. No differences were observed on the wet and dry yields, or on the protein content, fat and calcium retention of clots produced in the different experimental conditions. The instrumental evaluation showed that calcium addition significantly influenced the texture of cheeses, regardless of the pH of milk clotting. The sensory panel did not find a difference in the hardness ofcheeses produced at the same pH of milk clotting in function of CaCl2 addition. There was no difference in the texture of Minascured cheese due to the calcium addition to milk for dairy product consumers, which brings a new perspective on manufacture for cheese markers.

Avaliou-se o efeito de diferentes condições de pH ­5,8 e 6,6 ­e da adição de cálcio ­0, 150, 300ppm de CaCl2 - sobre o rendimento, a retenção de nutrientes nos coágulos produzidos e a textura de queijo-de-Minas curado. Foram analisados nos coágulos os rendimentos úmido e seco, o percentual e a retenção de proteína, de gordura e de cálcio. A textura dos queijos foi avaliada por testes instrumental e sensorial. Não foram observadas diferenças nos rendimentos úmido e seco, no conteúdo percentual e na retenção de proteína, gordura e cálcio nos coágulos produzidos em diferentes condições experimentais. A análise instrumental mostrou que a adição ou não de cálcio influenciou a textura dos queijos, independentemente do pH de coagulação do leite. O painel sensorial não diferiu quanto à dureza dos queijos produzidos em um mesmo valor de pH de coagulação do leite mediante a adição de CaCl2. Para os consumidores, não houve diferença na textura do queijo Minas curado em razão da adição de cálcio ao leite. Isto traz nova perspectiva na fabricação para os produtores de queijo.

EEG and neuroimaging correlations in children with lissencephaly.

PURPOSE: To study the usefulness of EEG in the diagnosis of lissencephaly, a rare cortical developmental disorder associated with abnormal cellular proliferation. Currently, the clinical emphasis is placed on the radiological and genetic aspects for the diagnosis of lissencephaly. METHODS: This is a retrospective review of consecutive EEG recordings and imaging data from 14 children, with the diagnosis of lissencephaly, who were admitted from January 1998 to January 2010. All EEG recordings were performed with the 10-20 system of electrode placement, in both awake and sleep states. All EEG recordings were reviewed using anterior-posterior bipolar and transverse montages and then they were interpreted blindly, with respect to the imaging and genetic investigations for each patient. RESULTS: All children showed one of the three characteristic EEG patterns reported in the literature of lissencephaly. The EEG pattern I, showed an anterior posterior gradient that corresponded to the severity of the imaging study abnormality. All patients were on two or more AEDs and reported to continue having active epilepsy. CONCLUSION: In a child with clinical characteristics of lissencephaly, one of these three reported EEG patterns can prove useful in making the diagnosis very probable, preceding imaging and genetic testing.

Utilização de Lactobacillus acidophilus e de acidificação direta na fabricação de queijo de minas frescal / Lactobacillus acidophilus and of direct acidification to minas frescal cheese production

Três procedimentos foram adotados na elaboração de queijo de minas frescal: fabricação tradicional, com adição de ácido lático e com Lactobacillus acidophilus. As amostras dos queijos foram analisadas quanto à composição e, durante o período de estocagem de 30 dias, quanto à acidez - pH e acidez titulável - e contagem de L. acidophilus. A análise sensorial foi realizada por métodos sensoriais afetivos. A composição dos queijos nos diferentes procedimentos apresentou-se de acordo com os padrões esperados, com exceção do teor de gordura, que foi maior no queijo com adição de ácido lático. Durante a armazenagem, ocorreu aumento da acidez titulável em todos os procedimentos. A contagem de L. acidophilus foi acima de 10(8)UFC/g, caracterizando populações suficientes para classificar o queijo como alimento probiótico. Na análise sensorial, o de queijo de minas com a adição do probiótico foi o preferido pelos julgadores. O queijo de minas frescal foi apropriado para incorporação do probiótico, e o uso de L. acidophilus melhorou a qualidade sensorial e não alterou os parâmetros físico-químicos.

Minas frescal cheese was produced in three different procedures: traditional manufacturing; with the addition of lactic acid; and with Lactobacillus acidophilus. Cheeses samples were analyzed for composition, and during the stock period of 30 days for acidity and L. acidophilus count. The sensory analysis was carried out through sensory affective methods. The composition of cheeses in different treatments presented results in accordance to the standards expected for the product, except for fat content, which was higher in cheese with the addition of lactic acid. During the stock period, an increase of titulable acidity in all treatments was observed. The L. acidophilus count was above 10(8)UFC/g, characterizing sufficient population to classify the cheese as a probiotic food. At the sensory analysis, it was attested that the cheese which had the addition of probiotic was preferred among the tasters. The Minas Frescal cheese was appropriate for incorporation of probiotic and the use of L. acidophilus in cheese improved the sensory quality and did not alter the physicochemical parameters.

Arrhythmia and sudden death associated with elevated cardiac chloride channel activity.

The identification and analysis of several cationic ion channels and their associated genes have greatly improved our understanding of the molecular and cellular mechanisms of cardiac arrhythmia. Our objective in this study was to examine the involvement of anionic ion channels in cardiac arrhythmia. We used a transgenic mouse model to overexpress the human cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a cAMP-regulated chloride channel. We used RNase protection and in situ hybridization assays to determine the level of CFTR expression, and radiotelemetry and in vivo electrophysiological study in combination with pharmacological intervention to analyse the cardiac function. Cardiac CFTR overexpression leads to stress-related sudden death in this model. In vivo intracardiac electrophysiological studies performed in anaesthetized mice showed no significant differences in baseline conduction parameters including atrial-His bundle (AH) or His bundle-ventricular (HV) conduction intervals, atrioventricular (AV) Wenckebach or 2:1 AV block cycle length and AV nodal functional refractory period. However, following isoproterenol administration, there was marked slowing of conduction parameters, including high-grade AV block in transgenic mice, with non-sustained ventricular tachycardia easily inducible using programmed stimulation or burst pacing. Our sudden death mouse model can be a valuable tool for investigation of the role of chloride channels in arrhythmogenesis and, potentially, for future evaluation of novel anti-arrhythmic therapeutic strategies and pharmacological agents.

Disruption of ClC-2 expression is associated with progressive neurodegeneration in aging mice.

Heterozygous mutations in ClC-2 have been associated in rare cases with increased susceptibility to generalized, idiopathic epilepsy. Initially, it was hypothesized that mutations in ClC-2 may be associated with epilepsy due to a direct role for ClC-2 in the modification of hippocampal neuronal excitability. However, the absence of an overt seizure-susceptibility phenotype in young ClC-2 knockout (KO) mice rendered this hypothesis- implausible. A recent study of older ClC-2 KO mice (>6 months) revealed abnormalities in the myelin of central axons and a subtle defect in the neuronal function in the central auditory pathway. These findings prompted us to re-examine hippocampal neuron morphology and excitability in older ClC-2 KO mice. Interestingly, electrocorticographic recordings obtained in older mice revealed spontaneous interictal spikes which are a marker of perturbed hippocampal neurotransmission with a resultant increase in excitation. This electrophysiological defect was associated with astrocyte activation and evidence of neuronal degeneration in the CA3 region of the hippocampus of these older mice. Together, these findings raise the possibility that ClC-2 expression plays a subtle neuroprotective role in the aging hippocampus.

Succinic semialdehyde dehydrogenase deficiency: lessons from mice and men.

Succinic semialdehyde dehydrogenase (SSADH) deficiency, a disorder of GABA degradation with subsequent elevations in brain GABA and GHB, is a neurometabolic disorder with intellectual disability, epilepsy, hypotonia, ataxia, sleep disorders, and psychiatric disturbances. Neuroimaging reveals increased T2-weighted MRI signal usually affecting the globus pallidus, cerebellar dentate nucleus, and subthalamic nucleus, and often cerebral and cerebellar atrophy. EEG abnormalities are usually generalized spike-wave, consistent with a predilection for generalized epilepsy. The murine phenotype is characterized by failure-to-thrive, progressive ataxia, and a transition from generalized absence to tonic-clonic to ultimately fatal convulsive status epilepticus. Binding and electrophysiological studies demonstrate use-dependent downregulation of GABA(A) and (B) receptors in the mutant mouse. Translational human studies similarly reveal downregulation of GABAergic activity in patients, utilizing flumazenil-PET and transcranial magnetic stimulation for GABA(A) and (B) activity, respectively. Sleep studies reveal decreased stage REM with prolonged REM latencies and diminished percentage of stage REM. An ad libitum ketogenic diet was reported as effective in the mouse model, with unclear applicability to the human condition. Acute application of SGS-742, a GABA(B) antagonist, leads to improvement in epileptiform activity on electrocorticography. Promising mouse data using compounds available for clinical use, including taurine and SGS-742, form the framework for human trials.

Effect of pH on characteristics of low-moisture Mozzarella cheese during refrigerated storage.

This study evaluated the effect of cheese pH on proteolysis, calcium distribution, and functional characteristics of Mozzarella cheese. On 4 occasions, cultured low-moisture part-skim Mozzarella cheeses were obtained from a commercial producer on the day after manufacture. Cheese blocks were randomly assigned to 2 groups. One group was shredded, subdivided, and exposed to either ammonia vapor to increase the pH or HCl vapor to decrease the pH. Samples were vacuum packaged, stored at 4 degrees C, and analyzed for pH 4.6 and 12% TCA soluble nitrogen, apparent viscosity, free oil, and water-soluble calcium on days 5, 12, 22, and 40. The 2nd group was sectioned into 23-mm thick slabs and similarly exposed to either ammonia vapor to increase the pH or HCl vapor to decrease the pH. The slabs were vacuum packaged, stored at 4 degrees C, and analyzed for pH 4.6 and 12% TCA soluble nitrogen, TPA hardness, springiness and cohesiveness, and meltability on days 17, 29, and 41. Data were analyzed by ANOVA according to a spilt-plot design. Experimentally induced pH differences persisted and significantly affected TPA hardness, apparent viscosity, meltability, and water-soluble calcium throughout 40 d of storage, but did not affect soluble nitrogen changes. Thus, cheese pH affected functional characteristics and calcium distribution but did not affect proteolysis rates. Higher cheese pH resulted in a harder cheese that required longer aging to develop desirable melting characteristics, whereas cheese with lower pH developed desirable melting characteristics more quickly but had a shorter functional shelf life.

Absence seizures in succinic semialdehyde dehydrogenase deficient mice: a model of juvenile absence epilepsy.

The succinic semialdehyde dehydrogenase (SSADH) null mouse represents a viable animal model for human SSADH deficiency and is characterized by markedly elevated levels of both gamma-hydroxybutyric acid (GHB) and gamma-aminobutyric acid (GABA) in brain, blood, and urine. GHB is known to induce absence-like seizures and absence seizures have been reported to occur in children with SSADH deficiency. We tested the hypothesis that the phenotype of the SSADH(-/-) mouse shows absence-like seizures because of the inordinately high levels of GHB in the brain of this mutant animal. Sequential electrocorticographic (ECoG) and prolonged video ECoG recordings from chronically implanted electrodes were done on SSADH(-/-), SSADH(+/-), and SSADH(+/+) mice from postnatal day (P) 10 to (P) 21. Spontaneous, recurrent absence-like seizures appeared in the SSADH(-/-) during the second week of life and evolved into generalized convulsive seizures late in the third week of life that were associated with an explosive onset of status epilepticus which was lethal. The seizures in SSADH null mice were consistent with typical absence seizures in rodent with 7 Hz spike-and-wave discharge (SWD) recorded from thalamocortical circuitry, the onset/offset of which was time-locked with ictal behavior characterized by facial myoclonus, vibrissal twitching and frozen immobility. The absence seizures became progressively more severe from P14 to 18 at which time they evolved into myoclonic and generalized convulsive seizures that progressed into a lethal status epilepticus. The absence seizures in SSADH(-/-) were abolished by ethosuximide (ETX) and the GABA(B)R antagonist CGP 35348. The seizure phenotype in the SSADH(-/-) recapitulates that observed in human SSADH deficiency. Hence, SSADH(-/-) may be used to investigate the molecular mechanisms that underpin the pathogenesis of absence and generalized tonic-clonic seizures associated with SSADH deficiency. As well, the SSADH(-/-) may represent a unique animal model of the transition from absence to myoclonic and generalized convulsive seizures that is observed in up to 80% of patients with juvenile absence epilepsy.

Gamma-hydroxybutyric acid-induced absence seizures in GluR2 null mutant mice.

In this electrophysiological study, we examined the susceptibility of GluR2 mutant null mice to absence seizures in comparison with wild-type controls. The prodrug of (GHB), gamma-butyrolactone (GBL) was given systemically to induce the absence seizures. We also tested the severity and duration of the seizure activity in this model. The results showed that the latency from GBL administration to onset of seizure was significantly prolonged in GluR2(-/-) mice when compared to GluR2(+/+) mice. The duration of spike-and-wave discharges (SWD) was also significantly decreased in the GluR2(-/-) mice. Ninety minutes following GBL administration, wild-type animals continued to exhibit intermittent SWD bursts while GluR2(-/-) mice had returned to baseline. These data suggest that the GluR2 subunit may be involved in the initiation and maintenance of absence seizures induced by GBL.

Alteration of GLUR2 expression in the rat brain following absence seizures induced by gamma-hydroxybutyric acid.

We explored the involvement of the glutamate receptor subunit B (GluR2) in the mechanism of absence seizures induced by gamma-hydroxybutyric acid (GHB). The expression and distribution of GluR2 protein in rat brain were examined during and after GHB-induced absence seizures. The data indicate that GluR2 protein expression significantly decreases following the onset of absence seizures. The suppression of GluR2 expression was prolonged and it outlasted the duration of the continuous absence seizure activity. The alteration of GluR2 protein levels was accompanied by a re-distribution of GluR2 expression from laminae V to IV in cerebral cortex. We also analyzed the duration and latency of absence seizures induced by GHB 72 h following an initial GHB-induced absence seizure, a time when suppression of GluR2 protein was maximal. The second absence seizure was significantly more prolonged than the first. These data may indicate that the putative down-regulation of GluR2 following GHB-induced absence seizure could have contributed to the potentiation of subsequent seizures in animals. A related hypothesis posed by the data is that down-regulation of GluR2 is involved in the mechanisms of the maintenance of recurrent absence seizure activity once it is initiated and therefore, may contribute to the chronicity of seizures in absence epilepsy.

A model of atypical absence seizures: EEG, pharmacology, and developmental characterization.

OBJECTIVE AND BACKGROUND: Atypical absence seizures differ markedly from typical absence seizures in EEG findings, ictal behavior, and neurodevelopmental outcome. The object of these experiments was to provide electrical, behavioral, pharmacologic, and developmental characterization of a putative animal model of atypical absence seizures. METHODS: Atypical absence seizures were induced in Long Evans hooded rats by treatment with a cholesterol biosynthesis inhibitor, AY-9944 (AY), during development. Prolonged video EEG recordings were made from chronically implanted depth electrodes in the waking and sleep states in adult and developing animals during and after AY treatment. Also, the response of AY-induced atypical absence seizures to drugs known to exacerbate and block typical absence seizures was ascertained. RESULTS: AY treatment resulted in spontaneous, bilaterally synchronous, slow spike-and-wave discharges (SWD), which were frequent, recurrent, prolonged, and lifelong. SWD began as early as postnatal day 21, occurred throughout all stages of sleep, and were associated with myoclonic jerks during sleep. The SWD were significantly prolonged by carbamazepine, gamma-hydroxybutyrate, and the gamma-aminobutyrate type B (GABA(B)) receptor (GABA(B)R) agonist baclofen. AY-induced seizures were abolished by diazepam, ethosuximide, and the GABA(B)R antagonist CGP 35348 but returned as the drugs were eliminated. Atypical features of absence seizures in this model are slow spike-wave, emanation of SWD from hippocampus, gradual onset and offset of ictal behavior, and the ability of the animals to move during the spike-and-wave bursts. CONCLUSION: The AY-treated rat represents a predictable, reproducible, and clinically relevant animal model of atypical absence seizures that may be used to investigate the pathogenesis and treatment of this malignant disorder.

Type I diabetes and multiple sclerosis patients target islet plus central nervous system autoantigens; nonimmunized nonobese diabetic mice can develop autoimmune encephalitis.

Type I diabetes and multiple sclerosis (MS) are distinct autoimmune diseases where T cells target either islet or CNS self-proteins. Unexpectedly, we found that autoreactive T cells in diabetic patients, relatives with high diabetes risk, nonobese diabetic (NOD) mice, and MS patients routinely target classical islet as well as CNS autoantigens. The pathogenic potential of CNS autoreactivity was testable in NOD mice. Pertussis holotoxin, without additional Ags or adjuvants, allowed development of an NOD mouse-specific, autoimmune encephalitis with variable primary-progressive, monophasic, and relapsing-remitting courses. T cells from diabetic donors transferred CNS disease to pertussis toxin-pretreated NOD.scid mice, with accumulation of CD3/IFN-gamma transcripts in the brain. Diabetes and MS appear more closely related than previously perceived. NOD mouse-specific, autoimmune encephalitis provides a new MS model to identify factors that determine alternative disease outcomes in hosts with similar autoreactive T cell repertoires.

Recurrent seizures in metachromatic leukodystrophy.

The unusual presentation of juvenile onset metachromatic leukodystrophy (MLD) and frequent complex partial seizures in a patient led us to perform a retrospective study of 18 patients with MLD to identify the prevalence and type of recurrent seizures during the first 2 years of the disease. Five of 17 patients (29%) had developed recurrent seizures within 12 months of the onset of symptoms, and one patient was lost to follow-up. By 24 months after onset of symptoms, 5 patients were lost to follow-up, and 6 of the remaining 13 patients (46%) had developed recurrent seizures. In all, 7 patients, 4 with late infantile-onset and 3 with juvenile-onset disease, developed recurrent seizures. Four patients, including 3 with juvenile-onset disease had complex partial seizures. We conclude that recurrent seizures are common in MLD and may occur at any stage of the disease, particularly in patients with juvenile onset. Generalized seizures are more frequent in patients with late infantile-onset, whereas partial seizures are more common in those with juvenile-onset disease.

Infantile spasms: seasonal onset differences and zeitgebers.

The health records of 76 infants with infantile spasms (IS) were reviewed retrospectively. The distribution of seizure onset was examined with respect to calendar month, annual changes in day length (photoperiod), and global solar radiation (GSR). IS onset was more frequent during the months with low GSR and short photoperiods. The greatest frequency of IS onset was in December and January (22 cases, 29%); the lowest was in April and May (8 cases, 10.5%). IS onset frequency (f) was more than twice as great in the months with a short photoperiod (10Light-14Dark) and a low GSR (f = 11) as compared with months with a long photoperiod (16Light-8Dark) and a high GSR (f = 5). IS onset frequency was 2.2-fold greater in months with a short photoperiod and a low GSR. This finding suggests that environmental photoperiodic factors (zeitgebers) may play a role in the onset of IS.