Outcomes of epileptic spasms in patients aged less than 3 years: single-center United States experience

Computational EEG attributes predict response to therapy for epileptic spasms

OBJECTIVE

We set out to evaluate whether response to treatment for epileptic spasms is associated with specific candidate computational EEG biomarkers, independent of clinical attributes.

METHODS

We identified 50 children with epileptic spasms, with pre- and post-treatment overnight video-EEG. After EEG samples were preprocessed in an automated fashion to remove artifacts, we calculated amplitude, power spectrum, functional connectivity, entropy, and long-range temporal correlations (LRTCs). To evaluate the extent to which each feature is independently associated with response and relapse, we conducted logistic and proportional hazards regression, respectively.

RESULTS

After statistical adjustment for the duration of epileptic spasms prior to treatment, we observed an association between response and stronger baseline and post-treatment LRTCs (P = 0.042 and P = 0.004, respectively), and higher post-treatment entropy (P = 0.003). On an exploratory basis, freedom from relapse was associated with stronger post-treatment LRTCs (P = 0.006) and higher post-treatment entropy (P = 0.044).

CONCLUSION

This study suggests that multiple EEG features-especially LRTCs and entropy-may predict response and relapse.

SIGNIFICANCE

This study represents a step toward a more precise approach to measure and predict response to treatment for epileptic spasms.

Landscape of genetic infantile epileptic spasms syndrome-A multicenter cohort of 124 children from India

OBJECTIVE

Literature on the genotypic spectrum of Infantile Epileptic Spasms Syndrome (IESS) in children is scarce in developing countries. This multicentre collaboration evaluated the genotypic and phenotypic landscape of genetic IESS in Indian children.

METHODS

Between January 2021 and June 2022, this cross-sectional study was conducted at six centers in India. Children with genetically confirmed IESS, without definite structural-genetic and structural-metabolic etiology, were recruited and underwent detailed in-person assessment for phenotypic characterization. The multicentric data on the genotypic and phenotypic characteristics of genetic IESS were collated and analyzed.

RESULTS

Of 124 probands (60% boys, history of consanguinity in 15%) with genetic IESS, 105 had single gene disorders (104 nuclear and one mitochondrial), including one with concurrent triple repeat disorder (fragile X syndrome), and 19 had chromosomal disorders. Of 105 single gene disorders, 51 individual genes (92 variants including 25 novel) were identified. Nearly 85% of children with monogenic nuclear disorders had autosomal inheritance (dominant-55.2%, recessive-14.2%), while the rest had X-linked inheritance. Underlying chromosomal disorders included trisomy 21 (n = 14), Xq28 duplication (n = 2), and others (n = 3). Trisomy 21 (n = 14), ALDH7A1 (n = 10), SCN2A (n = 7), CDKL5 (n = 6), ALG13 (n = 5), KCNQ2 (n = 4), STXBP1 (n = 4), SCN1A (n = 4), NTRK2 (n = 4), and WWOX (n = 4) were the dominant single gene causes of genetic IESS. The median age at the onset of epileptic spasms (ES) and establishment of genetic diagnosis was 5 and 12 months, respectively. Pre-existing developmental delay (94.3%), early age at onset of ES (<6 months; 86.2%), central hypotonia (81.4%), facial dysmorphism (70.1%), microcephaly (77.4%), movement disorders (45.9%) and autistic features (42.7%) were remarkable clinical findings. Seizures other than epileptic spasms were observed in 83 children (66.9%). Pre-existing epilepsy syndrome was identified in 21 (16.9%). Nearly 60% had an initial response to hormonal therapy.

SIGNIFICANCE

Our study highlights a heterogenous genetic landscape and phenotypic pleiotropy in children with genetic IESS.

Early-Life Epilepsies

Epilepsies are a diverse group of neurological disorders characterized by recurrent seizures. One-third of epilepsies are refractory to standard antiseizure medications. Epilepsy incidence is age-dependent with high incidence in neonates and infants. Epilepsy syndromes are classified based on clinical, electrographic, neuroimaging, age-dependent features of onset and the possibility of remission. Advances in genetic testing technology and improved access to clinical genetic testing, including whole exome sequencing, have facilitated a fundamental shift in gene discovery of monogenetic and polygenetic epilepsy, leading to precision medicine therapy and improved outcomes. Here, we review the self-limited epilepsy syndromes and developmental and epileptic encephalopathies that begin in the neonatal-infantile period with an emphasis on genetic etiology and the shifting landscape of treatment options based on genetic findings. [Pediatr Ann. 2023;52(10):e381-e387.].

Inaccuracies in Parental Reporting of Treated Epileptic Spasms: Both Under- and Over-Reporting

BACKGROUND

The purpose of this study was to evaluate the accuracy of parental reporting of epileptic spasms (ES) after 14 days of appropriate medical therapy for new-onset ES by comparison with extended video electroencephalography (vEEG) monitoring results.

METHODS

Fifty-eight patients were identified from August 2019 to February 2021 with new-onset ES, confirmed on vEEG. Patients were initiated on appropriate treatment (high-dose steroids or vigabatrin). After two weeks of therapy, patients underwent overnight (18 to 24 hours) vEEG monitoring in the epilepsy monitoring unit. Parental reporting of presence or absence of ES on admission was compared with results of vEEG monitoring.

RESULTS

The 58 patients ranged in age from three to 20 months (average 7.8 months). An underlying etiology was identified in 78%, whereas 22% patients had unknown etiology. The overall accuracy of parental reporting was 74% (43 of 58) when compared with results of vEEG within 14 to 18 days of starting therapy. Of these, 65% (28 of 43) reported ES resolution and 35% (15 of 43) reported continued ES. Of the 26% (15 of 58) families who were incorrect at two-week follow-up, 67% (10 of 15) reported resolution of ES. However, a minority of families, 33% (five of 15), who continued to report spasms clinically, were inaccurate.

CONCLUSIONS

Although a majority of inaccurate parental reports at two weeks of treatment were due to unrecognized ES (a widely known phenomenon), a minority were conversely inaccurate due to persistent over-reporting of ES. This fact highlights the importance of correlating parental history with objective vEEG monitoring, to prevent inappropriate escalation of medication therapy.

Neurobehavioral deficits and a progressive ictogenesis in the tetrodotoxin model of epileptic spasms

OBJECTIVE

Our goal was to determine whether animals with a history of epileptic spasms have learning and memory deficits. We also used continuous (24/7) long-term electroencephalographic (EEG) recordings to evaluate the evolution of epileptiform activity in the same animals over time.

METHODS

Object recognition memory and object location memory tests were undertaken, as well as a matching to place water maze test that evaluated working memory. A retrospective analysis was undertaken of long-term video/EEG recordings from rats with epileptic spasms. The frequency and duration of the ictal events of spasms were quantified.

RESULTS

Rats with a history of epileptic spasms showed impairment on the three behavioral tests, and their scores on the object recognition memory and matching to place water maze tests indicated neocortical involvement in the observed impaired cognition. Analysis of EEG recordings unexpectedly showed that the ictal events of spasms and their accompanying behaviors progressively increased in duration over a 2-week period soon after onset, after which spasm duration plateaued. At the same time, spasm frequency remained unchanged. Soon after spasm onset, ictal events were variable in wave form but became more stereotyped as the syndrome evolved.

SIGNIFICANCE

Our EEG findings are the first to demonstrate progressive ictogenesis for epileptic spasms. Furthermore, in demonstrating cognitive deficits in the tetrodotoxin model, we have met a criterion for an animal model of West syndrome. Animal models will allow in-depth studies of spasm progression's potential role in cognitive regression and may elucidate why early treatment is considered essential for improved neurodevelopmental outcomes in children.

Epilepsy and Neurodevelopmental Outcomes in a Cohort of West Syndrome Beyond Two Years of Age

OBJECTIVE

To determine epilepsy and neurodevelopmental outcomes beyond 2 y of age and their putative prognostic factors in children with West syndrome (WS).

METHODS

This cross-sectional study was initiated after approval from Institutional Ethics Committee. A follow-up cohort of 114 children (aged ≥ 2 y) diagnosed and treated for WS at the authors' center were assessed in-person for epilepsy and neurodevelopmental outcomes using Vineland Social Maturity Scale - Malin's adaptation for Indian children. Subsequently, age at onset, lead-time-to-treatment, etiology, and response to any of the standard therapies were analyzed as possible predictors of these outcomes.

RESULTS

Of 114 children (mean age: 55 ± 32 mo, 91 boys), structural etiology was the predominant underlying etiology (79.8%) for WS. At 2 y of age, 64% had ongoing seizures. At the last follow-up, 76% had social quotient < 55, and 39% had cerebral palsy (spastic quadriparesis in 21%). An underlying structural etiology was associated with ongoing seizures [OR (95% CI) 3.5 (1.4-9); p = 0.008] at 2 y of age and poor developmental outcomes [OR (95% CI): 3.3 (1.3-8.9); p = 0.016]. Complete cessation of spasms with the standard therapy was significantly associated with better seizure control [OR (95% CI): 5.4 (2.3-13); p < 0.001] and neurodevelopmental outcome [OR (95% CI): 5.2 (1.8-14.9); p < 0.001].

CONCLUSION

The majority of children with WS have a poor neurodevelopmental outcome and epilepsy control on follow-up. The underlying etiology and response to initial standard therapy for epileptic spasms have a prognostic role in predicting the neurological outcome in these patients on follow-up.

EEG biomarkers for the diagnosis and treatment of infantile spasms

Early diagnosis and treatment are critical for young children with infantile spasms (IS), as this maximizes the possibility of the best possible child-specific outcome. However, there are major barriers to achieving this, including high rates of misdiagnosis or failure to recognize the seizures, medication failure, and relapse. There are currently no validated tools to aid clinicians in assessing objective diagnostic criteria, predicting or measuring medication response, or predicting the likelihood of relapse. However, the pivotal role of EEG in the clinical management of IS has prompted many recent studies of potential EEG biomarkers of the disease. These include both visual EEG biomarkers based on human visual interpretation of the EEG and computational EEG biomarkers in which computers calculate quantitative features of the EEG. Here, we review the literature on both types of biomarkers, organized based on the application (diagnosis, treatment response, prediction, etc.). Visual biomarkers include the assessment of hypsarrhythmia, epileptiform discharges, fast oscillations, and the Burden of AmplitudeS and Epileptiform Discharges (BASED) score. Computational markers include EEG amplitude and power spectrum, entropy, functional connectivity, high frequency oscillations (HFOs), long-range temporal correlations, and phase-amplitude coupling. We also introduce each of the computational measures and provide representative examples. Finally, we highlight remaining gaps in the literature, describe practical guidelines for future biomarker discovery and validation studies, and discuss remaining roadblocks to clinical implementation, with the goal of facilitating future work in this critical area.

Assessing Risk for Relapse among Children with Infantile Spasms Using the Based Score after ACTH Treatment: A Retrospective Study

Introduction

Even though adrenocorticotropic hormone (ACTH) demonstrated powerful efficacy in the initially successful treatment of infantile spasms (IS), nearly one-half of patients whose spasms were once suppressed experienced relapse. There is currently no validated method for the prediction of the risk of relapse. The Burden of Amplitudes and Epileptiform Discharges (BASED) score is an electroencephalogram (EEG) grading scale for children with infantile spasms. We sought to determine whether an association exists between the BASED score after ACTH treatment and relapse after initial response with ACTH.

Methods

Children with IS who achieved initial response after ACTH treatment were selected as the study subjects. Those who experienced relapse within 12 months after ACTH treatment were categorized as the relapse group, and those who did not were categorized as the non-relapse group. Their general clinical data and EEG data (using BASED scoring) after ACTH treatment were collected, and compared between groups. Cox proportional hazards models were fit to determine factors associated with relapse.

Results

A total of 64 children with IS were enrolled in the study, of which 37 (57.8%) experienced a relapse, and the median duration after ACTH treatment was 3 (1.5, 6) months. The BASED score was significantly higher in the relapse group than in the non-relapse group. Cox modeling demonstrated that BASED score was independently associated with relapse. The patients with a score greater than or equal to 3 showed a high rate (89.3%) of relapse. The relapse group had stronger, more stable EEG functional networks than the non-relapse group, and there were obvious correlations between BASED score and functional connectivity.

Conclusion

This study suggests the BASED score after ACTH treatment has potential value as a predictor for relapse after initial response. Children with IS who have a BASED score greater than or equal to 3 after the initial response of ACTH carry a high risk of relapse within 1 year.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00347-7.

Comparison of Cosyntropin, Vigabatrin, and Combination Therapy in New-Onset Infantile Spasms in a Prospective Randomized Trial

Objective: In a randomized trial, we aimed to evaluate the efficacy of cosyntropin injectable suspension, 1 mg/mL, compared to vigabatrin for infantile spasms syndrome. An additional arm was included to assess the efficacy of combination therapy (cosyntropin and vigabatrin) compared with cosyntropin monotherapy. Methods: Children (2 months to 2 years) with new-onset infantile spasms syndrome and hypsarhythmia were randomized into 3 arms: cosyntropin, vigabatrin, and cosyntropin and vigabatrin combined. Daily seizures and adverse events were recorded, and EEG was repeated at day 14 to assess for resolution of hypsarhythmia. The primary outcome measure was the composite of resolution of hypsarhythmia and absence of clinical spasms at day 14. Fisher exact test was used to compare outcomes. Results: 37 children were enrolled and 34 were included in the final efficacy analysis (1 withdrew prior to treatment and 2 did not return seizure diaries). Resolution of both hypsarhythmia and clinical spasms was achieved in in 9 of 12 participants (75%) treated with cosyntropin, 1/9 (11%) vigabatrin, and 5/13 (38%) cosyntropin and vigabatrin combined. The primary comparison of cosyntropin versus vigabatrin was significant (64% [95% confidence interval 21, 82], P < .01). Adverse events were reported in all 3 treatment arms: 31 (86%) had an adverse event, 7 (19%) had a serious adverse event, and 15 (42%) had an adverse event of special interest with no difference between treatment arms. Significance: This randomized trial was underpowered because of incomplete enrollment, yet it demonstrated that cosyntropin was more effective for short-term outcomes than vigabatrin as initial treatment for infantile spasms.

Antiepileptogenic effects of rapamycin in a model of infantile spasms due to structural lesions

OBJECTIVE

Infantile spasms may evolve into persistent epilepsies including Lennox-Gastaut syndrome. We compared adult epilepsy outcomes in models of infantile spasms due to structural etiology (multiple-hit model) or focal cortical inflammation and determined the anti-epileptogenic effects of pulse-rapamycin, previously shown to stop spasms in multiple-hit rats.

METHODS

Spasms were induced in 3-day-old male rats via right intracerebral doxorubicin/lipopolysaccharide (multiple-hit model) infusions. Controls and sham rats were used. Separate multiple-hit rats received pulse-rapamycin or vehicle intraperitoneally between postnatal days 4 and 6. In adult mice, video-EEG (electroencephalography) scoring for seizures and sleep and histology were done blinded to treatment.

RESULTS

Motor-type seizures developed in 66.7% of multiple-hit rats, usually from sleep, but were reduced in the pulse-rapamycin-treated group (20%, p = .043 vs multiple-hit) and rare in other groups (0-9.1%, p < .05 vs multiple-hit). Spike-and-wave bursts had a slower frequency in multiple-hit rats (5.4-5.8Hz) than in the other groups (7.6-8.3Hz) (p < .05); pulse rapamycin had no effect on the hourly spike-and-wave burst rates in adulthood. Rapamycin, however, reduced the time spent in slow-wave-sleep (17.2%), which was increased in multiple-hit rats (71.6%, p = .003). Sham rats spent more time in wakefulness (43.7%) compared to controls (30.6%, p = .043). Multiple-hit rats, with or without rapamycin treatment, had right more than left corticohippocampal, basal ganglia lesions. There was no macroscopic pathology in the other groups.

SIGNIFICANCE

Structural corticohippocampal/basal ganglia lesions increase the risk for post-infantile spasms epilepsy, Lennox-Gastaut syndrome features, and sleep dysregulation. Pulse rapamycin treatment for infantile spasms has anti-epileptogenic effects, despite the structural lesions, and decreases the time spent in slow wave sleep.

Definitions and Diagnostic Criteria for Infantile Spasms and West Syndrome - Historical Perspectives and Practical Considerations

The term infantile spasms has been used inconsistently within the medical literature for decades. We are also without formal consensus on the diagnostic criteria for West syndrome. Author-specific definitions for these terms will determine the populations studied within research studies and thus impact the relevance of the data acquired. In addition, how one defines these terms may have serious consequences for children presenting with infantile spasms such as the inappropriate withholding of standard therapy in those who fail to meet criteria for West syndrome. The overreliance on the term hypsarhythmia is particularly problematic given that many children presenting with infantile spasms will not have this classic pattern and because the determination of hypsarhythmia has poor inter-rater reliability. Herein I review historical perspectives, relying heavily on published monographs and consensus statements, and promote practical definitions and diagnostic criteria for infantile spasms and West syndrome. In an effort to encourage best clinical practice and research methodology, I include guidance for the diagnosis of infantile spasms (a seizure type) and West syndrome (an epilepsy syndrome).

Effect of intramuscular ACTH versus oral prednisolone on the developmental trajectories of children with West syndrome over 24 months: A randomised control study

OBJECTIVE

To assess the developmental progression and compare the developmental attainments of children treated with two hormonal therapies for infantile spasms (IS) over two years (seizure and EEG outcomes of this RCT published previously).

METHODS

Newly diagnosed infants with IS were randomised to receive adrenocorticotrophin (ACTH) or prednisolone for 14 days. All underwent Bayley III Infant and Toddler Assessments in cognitive (Cog), receptive (RC) and expressive (EC) communication, fine (FM) and gross (GM) motor developmental subsets at baseline (T0), one-year (T1) and two-years (T2).

RESULTS

95 infants randomised to prednisolone (n = 48) and ACTH (n = 47) groups were eligible for developmental assessments. Mean age at initial assessment was 8.75 months (SD = 6.37, range 1.46-34.4 months). 48 children presented for all three assessments. Mean composite scores of each developmental domain improved across the three time points; but the progression was significant only in relation to motor development (p = 0.04). When comparing the treatment outcomes at 2-years, mean composite scores of children treated with ACTH were significantly lower in motor domain (p = 0.023). As for developmental delay, the ACTH group (n = 32) showed significant delay in expressive communication (adjusted OR 5.46, 95% CI: 1.1, 28.57; p = 0.04) and fine motor (adjusted OR 9.4, 95% CI: 1.1, 83.3; p = 0.04) at T2 compared to the prednisolone (n = 30) in a regression analysis.

CONCLUSION

The number of children with delay at the 2 year follow up were significantly higher in two domains in the ACTH group compared to the prednisolone group. Overall results do not show a significant advantage of ACTH over prednisolone for developmental outcomes at two years, but further comparative studies over longer periods are required for more definitive conclusions.

A reliable interictal EEG grading scale for children with infantile spasms - The 2021 BASED score

OBJECTIVE

To develop an improved interictal electroencephalogram (EEG) grading scale for children with infantile spasms founded on elements with adequate inter-rater reliability (IRR) to justify its further study for clinical and research purposes.

METHODS

Three blinded reviewers assessed five-minute sleep epochs in 93 EEGs from 62 children (31 consecutive controls, 31 consecutive infantile spasms [pretreatment and posttreatment studies]) using a longitudinal bipolar montage. We determined the IRR of background amplitude, epileptiform discharges, >3 spike foci (including <50 % or >50 %), grouped multifocal spikes, paroxysmal voltage attenuations, and symmetry of sleep spindles. Data were used to finalize the 2021 BASED (Burden of AmplitudeS and Epileptiform Discharges) score.

RESULTS

All elements included in the 2021 BASED score had moderate to near perfect IRR. Among controls, >200 μv background waves occurred commonly in the bilateral posterior temporal (T3-T5, T4-T6) and midline (Fz-Cz, Cz-Pz) regions. Excluding midline and occipital channels (which have normal high amplitude background waves), we designated abnormal high amplitude background waves as >200 μv for most channels, but >300 μv for T3-T5 and T4-T6. The IRR was moderate to near perfect for <50 % >3 spike foci, >50 % >3 spike foci, paroxysmal voltage attenuations, grouped multifocal spikes (GMFS), and symmetric sleep spindles. Paroxysmal voltage attenuations, GMFS, and >50 % >3 spike foci all significantly distinguished pretreatment from posttreatment studies whereas symmetric sleep spindles did not (as planned, the latter was not included in the 2021 BASED score). When the 2021 BASED score was applied to the 22 children with infantile spasms achieving clinical remission with treatment, 19 met criteria for electroclinical remission and three did not.

SIGNIFICANCE

The 2021 BASED score includes elements with high levels of IRR and correlates well with the presence or absence of infantile spasms.

Developmental profile at initial presentation in children with infantile spasms

AIM

To describe the baseline developmental profile and influence of clinical and demographic factors on the developmental skills of infants diagnosed with infantile spasms.

METHOD

Ninety-five infants (55 males, 40 females) newly diagnosed with infantile spasms were recruited for a cross-sectional, longitudinal study. All infants underwent Bayley Scales of Infant and Toddler Development assessments in the cognitive, receptive communication, expressive communication, and fine and gross motor developmental domains; they also underwent visual, auditory, and social behaviour assessments. Infants were categorized as 'early' (<6mo) or 'late' (≥6mo) presenters; if presented within 28 days, this was considered as 'early presentation', whereas a delay greater than 28 days was considered as a 'delay in presentation'. Antenatal, perinatal, and postnatal risk factors were identified.

RESULTS

Over 90% of infants showed impairment in all domains, with the majority having severe delay; 99% showed cognitive impairment. Delayed presentation was significantly associated with receptive communication delay (odds ratio [OR]=5.35; 95% confidence interval [CI]=1.05-27.32). Onset at 6 months or less influenced auditory (OR=2.8; 95% CI=1.16-6.8) and visual (OR=3.03; 95% CI=1.22-7.57) behaviours. Neonatal infections impacted both receptive (OR=1.12; 95% CI=1.04-1.2) and expressive communication (OR=1.08; 95% CI=1.02-1.14) delay. Neonatal seizures significantly influenced visual, auditory, and social impairments. Expressive communication and gross motor development shared common perinatal risk factors.

INTERPRETATION

Adverse developmental status at presentation, associated with delayed presentation and neonatal risk factors should alert clinicians to the surveillance of at-risk infants and seek out timely interventions.

WHAT THIS PAPER ADDS

Ninety per cent of infants showed impaired cognitive, communication, and motor skills at presentation. Visual, auditory, and social behaviour impairments were significantly associated with perinatal risks. Visual, auditory, and social behaviour impairments were significantly associated with neonatal seizures.

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.

Neonatal and Infantile Epilepsy: Acquired and Genetic Models

The incidence of seizures and epilepsies is particularly high during the neonatal and infantile periods. We will review selected animal models of early-life epileptic encephalopathies that have addressed the dyscognitive features of frequent interictal spikes, the pathogenesis and treatments of infantile spasms (IS) or Dravet syndrome, disorders with mammalian target of rapamycin (mTOR) dysregulation, and selected early-life epilepsies with genetic defects. Potentially pathogenic mechanisms in these conditions include interneuronopathies in IS or Dravet syndrome and mTOR dysregulation in brain malformations, tuberous sclerosis, and related genetic disorders, or IS of acquired etiology. These models start to generate the first therapeutic drugs, which have been specifically developed in immature animals. However, there are challenges in translating preclinical discoveries into clinically relevant findings. The advances made so far hold promise that the new insights may potentially have curative or disease-modifying potential for many of these devastating conditions.

MRI findings in infants with infantile spasms after neonatal hypoxic-ischemic encephalopathy

BACKGROUND

To evaluate the predominant pattern of brain injury and the anatomic areas of injury in children with infantile spasms following neonatal hypoxic-ischemic encephalopathy.

METHODS

A nested case-control study of infantile spasms in children with term neonatal hypoxic-ischemic encephalopathy was performed. All patients had T1/T2-weighted magnetic resonance imaging with diffusion-weighted imaging performed on the third day of life. Using a validated scoring system, the magnetic resonance imaging was classified as: normal, watershed, basal ganglia/thalamus, total, or focal-multifocal. Two study investigators scored additional anatomic areas of injury (cortical extent, levels of the brainstem, hypothalamus) on T1/T2-weighted magnetic resonance imaging and diffusion-weighted imaging blinded to the outcome. The predominant pattern of brain injury and anatomic areas of injury were compared between patients who developed infantile spasms and randomly selected controls.

RESULTS

Eight patients who developed infantile spasms were identified among a cohort of 176 term newborns with hypoxic-ischemic encephalopathy (4.5%). There were no significant differences in the perinatal and neonatal course between newborns who developed infantile spasms and controls who did not. The development of infantile spasms after neonatal hypoxic-ischemic encephalopathy was significantly associated with basal ganglia/thalamus and total brain injury (P = 0.001), extent of cortical injury greater than 50% (odds ratio = 11.7, 95% confidence interval = 1.1-158.5, P = 0.01), injury to the midbrain (odds ratio = 13, 95% confidence interval = 1.3-172, P = 0.007) and hypothalamic abnormalities (P = 0.01).

CONCLUSIONS

The development of infantile spasms after hypoxic-ischemic encephalopathy is associated with injury to the basal ganglia and thalami on neonatal magnetic resonance imaging, particularly when extensive cortical injury and/or injury to the midbrain is present.