A stereo EEG study in a patient with sleep-related hypermotor epilepsy due to DEPDC5 mutation.

PURPOSE: Dishevelled EGL-10 and pleckstrin domain-containing protein 5 (DEPDC5) mutations are found in a wide spectrum of focal epilepsies ranging from epilepsy caused by malformation of cortical development to non-lesional epilepsy, including sleep-related hypermotor epilepsy (SHE). A surgical approach has been anecdotally reported in patients with DEPDC5 mutations, but most of these cases had a lesional etiology. METHODS: We describe a stereo-EEG (SEEG) study in a patient with drug-resistant/non-lesional SHE. Patient was screened for known mutations associated with SHE. RESULTS: SEEG disclosed bilateral synchronous and independent activity prevailing on the right central-anterior cingulate cortex, without a clear spatially defined epileptogenic zone. Due to the lack of a clear epileptogenic zone, surgery was contraindicated. Years later a DEPDC5 mutation was identified. CONCLUSION: We suggest that genetic analysis should be considered before performing SEEG study in a patient with drug resistant non-lesional SHE, in the presence of seizures in wakefulness and unclear anatomo-electroclinical correlation. If DEPDC5 mutations are identified, the presurgical evaluation should be tailored to look for MRI-negative focal cortical dysplasia and a wide epileptogenic network. The appropriate management and potential benefit of surgery for genetic non-lesional epilepsy have yet to be clarified.

Epilepsy with auditory features: A heterogeneous clinico-molecular disease.

OBJECTIVE: To identify novel genes implicated in epilepsy with auditory features (EAF) in phenotypically heterogeneous families with unknown molecular basis. METHODS: We identified 15 probands with EAF in whom an LGI1 mutation had been excluded. We performed electroclinical phenotyping on all probands and available affected relatives. We used whole-exome sequencing (WES) in 20 individuals with EAF (including all the probands and 5 relatives) to identify single nucleotide variants, small insertions/deletions, and copy number variants. RESULTS: WES revealed likely pathogenic variants in genes that had not been previously associated with EAF: a CNTNAP2 intragenic deletion, 2 truncating mutations of DEPDC5, and a missense SCN1A change. CONCLUSIONS: EAF is a clinically and molecularly heterogeneous disease. The association of EAF with CNTNAP2, DEPDC5, and SCN1A mutations widens the phenotypic spectrum related to these genes. CNTNAP2 encodes CASPR2, a member of the voltage-gated potassium channel complex in which LGI1 plays a role. The finding of a CNTNAP2 deletion emphasizes the importance of this complex in EAF and shows biological convergence.

Diagnostic accuracy of a structured interview for nocturnal frontal lobe epilepsy (SINFLE): a proposal for developing diagnostic criteria.

OBJECTIVES: To measure the accuracy of anamnestic features collected during clinical history for the diagnosis of nocturnal frontal lobe epilepsy (NFLE). METHODS: A case-control diagnostic study. Participants included a case group of people with ascertained target disease (NFLE group) and a control group of people with sleep disorders potentially confounding for NFLS (NOT-NFLE group), defined by means of a consensus procedure among experts (panel diagnosis as reference standard). Two major clinical patterns defining the semeiology of the epileptic event (i.e. dystonic, DP, and/or hyperkinetic pattern, HP), and 13 additional minor features were identified, formulated as questions, and telephonically administered to NFLE and NOT-NFLE groups by a trained doctor blinded to the final diagnosis. The diagnostic accuracy of each characteristic was tested against the reference standard. RESULTS: Out of 262 selected subjects, 101 were recruited; 42 were NFLE and 59 NOT-NFLE. A positive history of DP or HP had a sensitivity of 59.5% and a specificity of 91.5%, irrespective of the other minor anamnestic features. The anamnestic model improved, with a sensitivity of 59.5% and specificity of 96.6%, if at least one of the following four minor anamnestic features was added: (a) duration less than two minutes, (b) unstructured vocalization during the episode, (c) experience of an aura preceding the motor attack, and (d) a history of tonic-clonic seizures during sleep. CONCLUSIONS: The present study disclosed two major anamnestic patterns and four minor features that we called SINFLE, with unsatisfactory sensitivity but high specificity. These patterns could be the basis for developing future NFLE diagnostic criteria and to quantify the diagnostic accuracy of elements usually collected in the clinical history.

Parasomnias and nocturnal frontal lobe epilepsy (NFLE): lights and shadows--controversial points in the differential diagnosis.

Nocturnal frontal lobe epilepsy (NFLE) is characterized by seizures with complex, often bizarre, violent behaviour arising only or mainly during sleep. These unusual seizures and their occurrence during sleep are often accompanied by normal EEG tracings and neuroradiological findings, making it difficult to distinguish NFLE seizures from other non-epileptic nocturnal paroxysmal events, namely parasomnias. NFLE was described for the first time in 1981, but, as its epileptic origin was controversial, the condition was called nocturnal paroxysmal dystonia. Even though many aspects of parasomnias and NFLE have been clarified in the last two decades, the problem of differential diagnosis remains a challenge for clinicians. This paper discusses some controversial points still under debate. The difficulties in distinguishing nocturnal epileptic seizures from parasomnias reflect just one aspect of the intriguing issue of the pathophysiological relationships between all types of paroxysmal motor behaviours during sleep.