Epilepsy in children with tuberous sclerosis complex: Chance of remission and response to antiepileptic drugs

Objective

To describe treatment and outcome of epilepsy in children with tuberous sclerosis complex (TSC).

Methods

Seventy-one children with TSC and epilepsy treated at the ENCORE TSC Expertise Center between 1988 and 2014 were included. Patient characteristics and duration and effectiveness of antiepileptic treatments were extracted from our clinical database. Correlations were made between recurrence of seizures after response to treatment, and several patient characteristics.

Results

Median age at time of inclusion was 9.4 years (range 0.9–18.0). Seizure history showed that 55 children (77%) of 71 became seizure-free for longer than 1 month, and 21 (30%) of 71 for longer than 24 months. Remission of seizures was associated with higher IQ, and a trend was observed between seizure remission and age at onset of seizures. A total of 19 antiepileptic drugs (AEDs) were used. Valproic acid, vigabatrin, levetiracetam, and carbamazepine were used most frequently. Nonpharmacologic therapies (ketogenic diet, epilepsy surgery, and vagus nerve stimulation) were used 13 times. Epilepsy surgery was most effective, with four of five children becoming seizure-free. AEDs prescribed as first and second treatment were most effective. Valproic acid was prescribed most frequently as first and second treatment, followed by vigabatrin. Thirty-one children had infantile spasms, preceded by focal seizures in 18 children (58%). Vigabatrin was used by 29 children (94%), and was first treatment in 15 (48%). Vigabatrin was more effective than other AEDs when prescribed as first treatment.

Significance

We showed that, although 77% of children with epilepsy due to TSC reached seizure remission, usually after their first or second AED, this was sustained for at least 24 months in only 38%. Almost half of those with 24 months of remission later had relapse of seizures. Our results support vigabatrin as first choice drug, and show the need for better treatment options for these children.

Epilepsia 2015

Military blast exposure, ageing and white matter integrity

Mild traumatic brain injury, or concussion, is associated with a range of neural changes including altered white matter structure. There is emerging evidence that blast exposure—one of the most pervasive causes of casualties in the recent overseas conflicts in Iraq and Afghanistan—is accompanied by a range of neurobiological events that may result in pathological changes to brain structure and function that occur independently of overt concussion symptoms. The potential effects of brain injury due to blast exposure are of great concern as a history of mild traumatic brain injury has been identified as a risk factor for age-associated neurodegenerative disease. The present study used diffusion tensor imaging to investigate whether military-associated blast exposure influences the association between age and white matter tissue structure integrity in a large sample of veterans of the recent conflicts (n = 190 blast-exposed; 59 without exposure) between the ages of 19 and 62 years. Tract-based spatial statistics revealed a significant blast exposure × age interaction on diffusion parameters with blast-exposed individuals exhibiting a more rapid cross-sectional age trajectory towards reduced tissue integrity. Both distinct and overlapping voxel clusters demonstrating the interaction were observed among the examined diffusion contrast measures (e.g. fractional anisotropy and radial diffusivity). The regions showing the effect on fractional anisotropy included voxels both within and beyond the boundaries of the regions exhibiting a significant negative association between fractional anisotropy and age in the entire cohort. The regional effect was sensitive to the degree of blast exposure, suggesting a ‘dose-response’ relationship between the number of blast exposures and white matter integrity. Additionally, there was an age-independent negative association between fractional anisotropy and years since most severe blast exposure in a subset of the blast-exposed group, suggesting a specific influence of time since exposure on tissue structure, and this effect was also independent of post-traumatic stress symptoms. Overall, these data suggest that blast exposure may negatively affect brain-ageing trajectories at the microstructural tissue level. Additional work examining longitudinal changes in brain tissue integrity in individuals exposed to military blast forces will be an important future direction to the initial findings presented here.

Brain 2015

Why musical memory can be preserved in advanced Alzheimer’s disease

Musical memory is considered to be partly independent from other memory systems. In Alzheimer’s disease and different types of dementia, musical memory is surprisingly robust, and likewise for brain lesions affecting other kinds of memory. However, the mechanisms and neural substrates of musical memory remain poorly understood. In a group of 32 normal young human subjects (16 male and 16 female, mean age of 28.0 ± 2.2 years), we performed a 7 T functional magnetic resonance imaging study of brain responses to music excerpts that were unknown, recently known (heard an hour before scanning), and long-known. We used multivariate pattern classification to identify brain regions that encode long-term musical memory. The results showed a crucial role for the caudal anterior cingulate and the ventral pre-supplementary motor area in the neural encoding of long-known as compared with recently known and unknown music. In the second part of the study, we analysed data of three essential Alzheimer’s disease biomarkers in a region of interest derived from our musical memory findings (caudal anterior cingulate cortex and ventral pre-supplementary motor area) in 20 patients with Alzheimer’s disease (10 male and 10 female, mean age of 68.9 ± 9.0 years) and 34 healthy control subjects (14 male and 20 female, mean age of 68.1 ± 7.2 years). Interestingly, the regions identified to encode musical memory corresponded to areas that showed substantially minimal cortical atrophy (as measured with magnetic resonance imaging), and minimal disruption of glucose-metabolism (as measured with 18F-fluorodeoxyglucose positron emission tomography), as compared to the rest of the brain. However, amyloid-β deposition (as measured with 18F-flobetapir positron emission tomography) within the currently observed regions of interest was not substantially less than in the rest of the brain, which suggests that the regions of interest were still in a very early stage of the expected course of biomarker development in these regions (amyloid accumulation → hypometabolism → cortical atrophy) and therefore relatively well preserved. Given the observed overlap of musical memory regions with areas that are relatively spared in Alzheimer’s disease, the current findings may thus explain the surprising preservation of musical memory in this neurodegenerative disease.

Brain 2015

Progress in Intravenous Thrombolytic Therapy for Acute Stroke

Importance  Intravenous recombinant tissue plasminogen activator (alteplase) was approved by the US Food and Drug Administration in 1996 for the treatment of acute ischemic stroke. Nearly 20 years later, it remains the only approved treatment, despite limitations in both efficacy and safety. With a growing capacity for stroke treatment worldwide, physicians need to understand where we have come from and what the future of stroke treatment might be.

Objective  To present a historical prospective as well as current trends in thrombolytic therapy, focusing on characteristics of drugs that have worked and clinical trials that are moving the field forward.

Evidence Review  Sources are published pivotal clinical trials; seminal articles on physiology, pharmacology, and neuroimanging; and listings from clinical trial registries.

Findings  The slow progress in thrombolysis for acute stroke has been multifactorial. A focus on extending the time window for alteplase beyond 4.5 hours has encumbered substantial resources in the field for many years, yet these efforts have been largely unsuccessful. New drug development has also been slow. Several drugs have failed in clinical trials and currently only tenecteplase remains to be tested as a potential alternative to alteplase. The parallel pursuit for catheter-based interventional revascularization in acute stroke, which appears to be successful, has shifted emphasis away from pharmacologically based studies.

Conclusions and Relevance  Although the field of acute thrombolysis has been making progress slowly for many years, advances in neuroimaging and new clinical trials that combine thrombolytics with other pharmacological and interventional techniques are beginning to gain momentum once again. The emergence of new approaches based largely on combination therapy strategies has reset a course to advance thrombolytic treatment for acute stroke and promises to improve outcomes in acute stroke in the near future.

JAMA Neurology 2015

Diabetes Mellitus, Obesity, and Diagnosis of Amyotrophic Lateral Sclerosis A Population-Based Study

Importance  Although prior studies have suggested a role of cardiometabolic health on pathogenesis of amyotrophic lateral sclerosis (ALS), the association with diabetes mellitus has not been widely examined. Amyotrophic lateral sclerosis is the most common motor neuron disorder. Several vascular risk factors have been associated with decreased risk for ALS. Although diabetes is also a risk factor for vascular disease, the few studies of diabetes and ALS have been inconsistent.

Objective  To examine the association between diabetes and obesity, each identified throughInternational Statistical Classification of Diseases, Eighth or Tenth Revision codes in a hospital registry, and ALS using data from the Danish National Registers.

Design, Setting, and Participants  Population-based nested case-control study of 3650 Danish residents diagnosed as having ALS between January 1, 1982, and December 31, 2009, and 365 000 controls (100 for each ALS case) matched on age and sex. The analysis was conducted in September and October 2014.

Main Outcomes and Measures  Adjusted odds ratio for ALS associated with diabetes or obesity diagnoses at least 3 years prior to the ALS diagnosis date.

Results  When considering diabetes and our obesity indicator together, the estimated odds ratio for ALS was 0.61 (95% CI, 0.46-0.80) for diabetes and 0.81 (95% CI, 0.57-1.16) for obesity. We observed no effect modification on the association with diabetes by sex. We did find a significant modification by age at ALS diagnosis and age at first mention of diabetes in the hospital registers. The protective association was stronger with increasing age at ALS diagnosis (P = .01), and the odds ratio for first mention of diabetes was 1.66 (95% CI, 0.85-3.21) before age 40 years but 0.52 (95% CI, 0.39-0.70) for older ages. These results are consistent with different associations for type 1 vs type 2 diabetes.

Conclusions and Relevance  In this Danish nationwide study to investigate the association between diabetes and ALS diagnosis, our findings are in agreement with previous reports of a protective association between vascular risk factors and ALS and suggest that type 2 diabetes, but not type 1, is protective for ALS.

JAMA Neurology 2015

Transcriptional regulator PRDM12 is essential for human pain perception.

Pain perception has evolved as a warning mechanism to alert organisms to tissue damage and dangerous environments. In humans, however, undesirable, excessive or chronic pain is a common and major societal burden for which available medical treatments are currently suboptimal. New therapeutic options have recently been derived from studies of individuals with congenital insensitivity to pain (CIP). Here we identified 10 different homozygous mutations in PRDM12 (encoding PRDI-BF1 and RIZ homology domain-containing protein 12) in subjects with CIP from 11 families. Prdm proteins are a family of epigenetic regulators that control neural specification and neurogenesis. We determined that Prdm12 is expressed in nociceptors and their progenitors and participates in the development of sensory neurons in Xenopus embryos. Moreover, CIP-associated mutants abrogate the histone-modifying potential associated with wild-type Prdm12. Prdm12 emerges as a key factor in the orchestration of sensory neurogenesis and may hold promise as a target for new pain therapeutics.

Nat Genet 2015

Subjective cognitive concerns, amyloid-β, and neurodegeneration in clinically normal elderly

Objective: To determine whether neuroimaging biomarkers of amyloid-β (Aβ) and neurodegeneration (ND) are associated with greater self-reported subjective cognitive concerns (SCC) in clinically normal older individuals.

Methods: A total of 257 participants underwent Pittsburgh compound B PET, PET with fluorodeoxyglucose ¹⁸F, and structural MRI, as well as a battery of neuropsychological measures including several questionnaires regarding SCC. Individuals were classified into 4 biomarker groups: biomarker negative (Aβ−/ND−), amyloidosis alone (Aβ+/ND−), amyloidosis plus ND (Aβ+/ND+), and ND alone (Aβ−/ND+).

Results: Both Aβ and ND were independently associated with greater SCC controlling for objective memory performance. By contrast, neither Aβ nor ND was associated with objective memory performance controlling for SCC. Further examination revealed greater SCC in individuals with Aβ or ND positivity compared to biomarker-negative individuals. In addition, greater SCC predicted Aβ positivity when controlling for ND status.

Conclusions: When individuals were grouped by biomarker status, those who were positive on Aβ or ND had the highest report of SCC compared to biomarker-negative individuals. Findings were consistent when SCC was used to predict Aβ positivity. Taken together, results suggest that both Aβ and ND are associated with SCC, independent of objective memory performance. Enrichment of individuals with SCC may increase likelihood of Aβ and ND markers in potential participants for secondary prevention trials.

Neurology 2015