A new approach in anti-epileptic drug evaluation

Anticonvulsant activity of methanolic extract of Withania cogulans in mice

Mental and neurological diseases including depression, Parkinson's disease, dementia, epilepsy, anxiety disorders and bipolar disorders account for a considerable amount of the world's disease burden. Unfortunately, drugs used in the treatment of neurological diseases are expensive, symptomatic and they produce undesirable side effects. People from different cultures prefer to use medicinal plants for the treatment of various ailments ranging from plain to perplex disorders because they are most affordable, cost effective and easily accessible source of treatment in the primary healthcare system throughout the world. Withania coagulans, an erect grayish under-shrub belongs to family Solanaceae. It is common in Pakistan, East India, Iran and Afghanistan. The objective of this study was to analyze the anti-seizure activity of crude methanolic extract of Withania coagulans fruits (MeWc). For screening of this activity, maximal electroshock seizures model (MES) and chemically-induced seizures models were used. In maximal electroshock seizures test MeWc showed significant dose dependent percent protection against hind-limb tonic extension; significant and dose-dependent increase in latency to myoclonic jerks and tonic clonic convulsions and decrease in seizures duration were observed in PTZ-induced seizures. In strychnine-induced convulsions MeWc significantly increased latency to hind-limb tonic extension and percent protection from death in a dose-dependent manner. Thus, it was inferred from the experiments that extract of Withania coagulans showed anticonvulsant activity.

Analysis of EEG dynamics in epileptic children during carbamazepine therapy

Background: The analysis of the dynamics of background EEG characteristics on the different stages of CBZtherapy is very important for revealing the possible early predictors of benefit/adverse effects of the treatment and optimizing the anti-epileptic therapy. Objective: Evaluate the carbamazepine (CBZ) effect on the dynamics of EEG pattern in epileptic children at different stages of CBZ-monotherapy. Methods: Forty-five children (aged 3-9) with partial epilepsy were investigated. The EEG was recorded at rest and during functional tests prior to CBZ administration and three and six months after the initiation of CBZtherapy. Epileptiform graphoelements and baseline EEG activities were analyzed. Results: Following three months of CBZ-therapy an absolute power value in the low frequency bands of EEG spectrum increased while an average frequency of alpha waves decreased. During rest, CBZ reduced density of spontaneous epileptiform graphoelements and generalized epileptiform bursts. Generalized paroxysmal bursts decreased under functional tests. The EEG pattern maintained the same characteristics for six months. Deterioration of EEG pattern and clinical signs was observed in four children. Conclusion: Elevation of indices of low frequency bands, especially in occipital and parietal regions, concomitant with reduction of epileptiform elements and seizure frequency three months after initiation of therapy suggests that CBZ in appropriate doses might be continued. Otherwise, the strategy of antiepileptic therapy should be revised.

Is seizure frequency variance a predictable quantity?

Background

There is currently no formal method for predicting the range expected in an individual's seizure counts. Having access to such a prediction would be of benefit for developing more efficient clinical trials, but also for improving clinical care in the outpatient setting.

Methods

Using three independently collected patient diary datasets, we explored the predictability of seizure frequency. Three independent seizure diary databases were explored: SeizureTracker (n = 3016), Human Epilepsy Project (n = 93), and NeuroVista (n = 15). First, the relationship between mean and standard deviation in seizure frequency was assessed. Using that relationship, a prediction for the range of possible seizure frequencies was compared with a traditional prediction scheme commonly used in clinical trials. A validation dataset was obtained from a separate data export of SeizureTracker to further verify the predictions.

Results

A consistent mathematical relationship was observed across datasets. The logarithm of the average seizure count was linearly related to the logarithm of the standard deviation with a high correlation (R² > 0.83). The three datasets showed high predictive accuracy for this log-log relationship of 94%, compared with a predictive accuracy of 77% for a traditional prediction scheme. The independent validation set showed that the log-log predicted 94% of the correct ranges while the RR50 predicted 77%.

Conclusion

Reliably predicting seizure frequency variability is straightforward based on knowledge of mean seizure frequency, across several datasets. With further study, this may help to increase the power of RCTs, and guide clinical practice.

Emerging drugs for epilepsy and other treatment options

Epilepsies are amongst the most frequent chronic neurological conditions. Patients suffer from spontaneously recurring seizures because of sudden extensive electrical gray matter discharges. Although the current drug therapy allows many patients at least some degree of a satisfying course of the disease, a substantial number of patients remain without adequate seizure control. Reasons are either refractoriness to anticonvulsant drugs or intolerable drug-related side effects. Epilepsy surgery should be considered in these cases as possible treatment option. Nevertheless, a considerable rate of patients will not be suitable candidates or continue to have seizures despite surgery. Therefore there is a substantial need for better antiepileptic drugs. The aim of this review is to highlight currently emerging different treatment approaches which may ameliorate the perspectives of patients with difficult-to-treat epilepsies.

1H-MR spectroscopy indicates severity markers in temporal lobe epilepsy: correlations between metabolic alterations, seizures, and epileptic discharges in EEG

PURPOSE

In this study, hippocampal metabolite alterations in (1)H-MR spectroscopy ((1)H-MRS) were correlated to the findings of intensive video-EEG monitoring and duration of seizure symptoms in patients with temporal lobe epilepsy (TLE).

METHODS

The 14 patients with mesial TLE and no pathological findings in imaging were investigated by (1)H-MRS. Seizures were analyzed by: number of clinical seizures in 24 h, exact duration of clinical symptoms in 24 h, frequency of interictal epileptiform discharges (IEDs) and ictal activity, duration of ictal activity, and IEDs occurring within 24 h in intensive EEG monitoring. Pearson Correlation Coefficient (PCC) was calculated between spectral metabolite alterations and the parameters mentioned above.

RESULTS

In the analysis, a negative correlation was found between total (t) NAA values and degree of IEDs in EEG (p = 0.04); a positive correlation was found between Cr levels and duration of seizure symptoms registered by video monitoring (p = 0.01).

CONCLUSIONS

Our study shows that, in some patients, (1)H-MRS is able to refer the severity of TLE. The degree of tNAA reduction in (1)H-MRS, probably indicating neuronal dysfunction, is associated with interictal spiking in intensive EEG monitoring. Duration of seizure symptoms associated with increased Cr peaks probably reflects increased gliosis.

Influence of levetiracetame on ictal and postictal EEG in patients with partial seizures

To investigate the influence of levetiracetame (LEV) treatment on the interhemispheric seizure pattern propagation and postictal recovery of electroencephalography (EEG) background activity. Twenty-three adult patients (age > 16 years) with pharmacoresistant focal epilepsies presenting at the Epilepsy Center Erlangen for pre-surgical evaluation were enrolled in the study. Those eligible patients receiving only one antiepileptic drugs were recruited to the 48-h baseline phase and, after at least two seizures, were randomized to the 7-day treatment phase with either LEV (n = 11) or placebo (n = 12). All participants were submitted to continuous day-and-night video-EEG monitoring. The daily dose of LEV was 1000 mg (500 mg bid.) on the first treatment day and was increased to 2000 mg (1000 mg bid.) from the second day onward. The EEG changes relating to the time delay of the interhemispheric seizure pattern propagation and to the postictal recovery of the background activity were analysed by computerized video-EEG recording and compared using the non-parameter Mann-Whitney U-exact test (alpha = 0.05). A prolonged latency of the contralateral seizure pattern propagation was observed in the LEV group, whereas a more rapid propagation was observed in the placebo group (P = 0.009). Postictal generalized slowing of the background activity was recorded in 21 patients during the baseline phase. More rapid postictal recovery of the EEG background activity was observed in the LEV, but not in the placebo group (P = 0.03). This study demonstrated that LEV not only prevented the seizure pattern propagation but also helped the speedy recovery of the postictal background activity in the EEG.

Onset of Action of Levetiracetam: A RCT Trial Using Therapeutic Intensive Seizure Analysis (TISA)

OBJECTIVES

To correlate the onset of clinical effects of add-on levetiracetam (LEV) therapy with daily serum LEV concentration, in pharmaco-resistant focal epilepsies, using the TISA method.

METHODS

25 adult patients (aged>6 years) with pharmaco-resistant focal epilepsies undergoing presurgical evaluation at the Epilepsy Center Erlangen were enrolled in the study. Eligible patients on a maximum of one other antiepileptic drug (AED) were recruited into the 48-hour baseline phase. Those who had at least two seizures during this phase were randomized into the seven-day treatment phase, when they received either LEV or placebo, under continuous day-and-night video-EEG monitoring. The starting daily dose of LEV was 500 mg bid, titrated from the second treatment day to 1,000 mg bid. The peak serum concentration of LEV was monitored daily at 8:00 am (one hour after drug administration) for every patient. The number and duration of seizures per 24h (N/24h and D/24h respectively) were investigated.

RESULTS

23 patients completed the study (LEV group n=11 and placebo group n=12). Seven patients in the LEV group and two patients in the placebo group achieved seizure-freedom during the treatment phase. The intergroup comparison of the decrease in N/24h and D/24h from the baseline phase to the treatment phase was in favor of the LEV group (p<0.05). A significant effect of LEV on D/24h was seen as early as the second treatment day (p=0.013), becoming more apparent on the third treatment day (p=0.009).

CONCLUSION

The present study objectively quantified the correlation between the anticonvulsant effects of LEV in focal epilepsies and the peak serum concentration of the drug. For the first time, direct measurement was used to demonstrate the onset of action of LEV to be two days after drug initiation.

Proof of principle studies

Proof of Principle studies are an early stage of clinical drug development when a compound has shown potential in animal models and early safety testing. This step of proof-of-principle (PoP) or proof-of-concept (PoC) often links between Phase-I and dose ranging Phase-II studies. These small-scale studies are designed to detect a signal that the drug is active on a pathophysiologically relevant mechanism, as well as preliminary evidence of efficacy in a clinically relevant endpoint. Sponsors use these studies to estimate whether their compound might have clinically significant efficacy in other diseases states as well as epilepsy (e.g., migraine, neuropathic pain, anxiety, depression). Endpoints other than seizure frequency often reveal special characteristics of the drug. A structured dose escalation design can reveal dose-dependent effects and adverse effects, crossover studies can demonstrate change, presurgical studies can define efficacy, interictal discharges and photosensitivity models can explain changes in seizure features, transcranial magnetic stimulation evaluates hyperexcitability. PoP studies allow exploration of a wide range of potential therapeutic areas beyond epilepsy as part of an integrated CNS development plan.