Short- vs long-term assessment of heart rate variability: Clinical significance in Dravet Syndrome.

PURPOSE: Heart rate variability (HRV) is a promising prognostic biomarker in Dravet Syndrome (DS), but different studies are not always comparable, limiting its clinical application. In fact, multiple HRV parameters, analyzed over different timescales and in different states are reported. The aim of this study was to assess which HRV parameter is more reproducible and clinically significant, analyzing differences between wake and sleep. METHOD: Patients with DS, with available 24 h-ECG Holter-derived HRV, were screened to evaluate if they had EEG-derived ECG traces available within one month before/after the Holter. A 5-minute period in the awake and sleep state were analyzed and correlated with the 24 h-HRV. Several relevant clinical features such as age, a recent history of status epilepticus (SE), and frequent generalized tonic-clonic seizures (GTCS) were correlated to HRV parameters with multiple linear regression models. RESULTS: Thirty-oneawake recordings and 22 sleep recordings were included. HF was the parameter with the highest correlation in awake (Rho 0.745, p < 0.001) and in sleep (Rho 0.727, p < 0.001). Age was a significant factor in simple models for most of the parameters except RMSSD. A recent history of SE was associated with a significant reduction of HRV, both in simple and multiple regressions for all parameters except for awake LF and for sleep RMSSD and PNN50. Frequent GTCS were associated with a significant decrease in sleep RMSSD, HF, and LF, also when correcting for the effect of age and history of SE. When compared pairwise, a significant increase in sleep was seen for HF (median + 24.45 ms2, IQR -7.51/+172.18 ms2, p = 0.036; increase in 15/22 patients). CONCLUSION: A moderate degree of correlation between long- and short-term HRV was seen both in sleep and in awake, and a strong correlation for awake HF. HF, both in awake and sleep, was significantly associated with high seizure burden, including SE and frequent GTCS.

Heart rate variability modifications in adult patients with early versus late-onset temporal lobe epilepsy: A comparative observational study.

OBJECTIVES: Temporal lobe epilepsy (TLE) is the most frequent form of focal epilepsy. TLE is associated with cardio-autonomic dysfunction and increased cardiovascular (CV) risk in patients over the fifth decade of age. In these subjects, TLE can be classified as early-onset (EOTLE; i.e., patients who had developed epilepsy in their youth) and late-onset (LOTLE; i.e., patients who developed epilepsy in adulthood). Heart rate variability (HRV) analysis is useful for assessing cardio-autonomic function and identifying patients with increased CV risk. This study compared changes in HRV occurring in patients over the age of 50, with EOTLE or LOTLE. METHODS: We enrolled twenty-seven adults with LOTLE and 23 with EOTLE. Each patient underwent a EEG and EKG recording during 20-minutes of resting state and a 5-minutes hyperventilation (HV). Short-term HRV analysis was performed both in time and frequency domains. Linear Mixed Models (LMM) were used to analyze HRV parameters according to the condition (baseline and HV) and group (LOTLE and EOTLE groups). RESULTS: Compared to the LOTLE group, the EOTLE group showed significantly decreased LnRMSSD (natural logarithm of the root mean square of the difference between contiguous RR intervals) (p-value=0.05), LnHF ms2 (natural logarithm of high frequency absolute power) (p-value=0.05), HF n.u. (high frequency power expressed in normalized units) (p-value=0.008) and HF% (high frequency power expressed in percentage) (p-value=0.01). In addition, EOTLE patients exhibited increased LF n.u. (low frequency power expressed in normalized units) (p-value=0.008) and LF/HF (low frequency/high frequency) ratio (p-value=0.007). During HV, the LOTLE group exhibited a multiplicative effect for the interaction between group and condition with increased LF n.u. (p = 0.003) and LF% (low frequency expressed in percentage) (p = 0.05) values. CONCLUSIONS: EOTLE is associated with reduced vagal tone compared to LOTLE. Patients with EOTLE may have a higher risk of developing cardiac dysfunction or cardiac arrhythmia than LOTLE patients.

Linear Diagnostic Procedure Elicited by Clinical Genetics and Validated by mRNA Analysis in Neuronal Ceroid Lipofuscinosis 7 Associated with a Novel Non-Canonical Splice Site Variant in MFSD8.

Neuronal ceroid lipofuscinoses (CNL) are lysosomal storage diseases that represent the most common cause of dementia in children. To date, 13 autosomal recessive (AR) and 1 autosomal dominant (AD) gene have been characterized. Biallelic variants in MFSD8 cause CLN7 type, with nearly 50 pathogenic variants, mainly truncating and missense, reported so far. Splice site variants require functional validation. We detected a novel homozygous non-canonical splice-site variant in MFSD8 in a 5-year-old girl who presented with progressive neurocognitive impairment and microcephaly. The diagnostic procedure was elicited by clinical genetics first, and then confirmed by cDNA sequencing and brain imaging. Inferred by the common geographic origin of the parents, an autosomal recessive inheritance was hypothesized, and SNP-array was performed as the first-line genetic test. Only three AR genes lying within the observed 24 Mb regions of homozygosity were consistent with the clinical phenotype, including EXOSC9, SPATA5 and MFSD8. The cerebral and cerebellar atrophy detected in the meantime by MRI, along with the suspicion of accumulation of ceroid lipopigment in neurons, prompted us to perform targeted MFSD8 sequencing. Following the detection of a splice site variant of uncertain significance, skipping of exon 8 was demonstrated by cDNA sequencing, and the variant was redefined as pathogenic.