Hypomotor · PDF file •EEG different, LP focus. More information on seizure semiology...

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Transcript of Hypomotor · PDF file •EEG different, LP focus. More information on seizure semiology...

  • Hypomotor seizures Liisa Metsähonkala, MD, PhD


    Helsinki University Hospital

  • Hypomotor seizures

    • seizure type seen in infants, small children and nonverbal patients (Duchowny 1992, Acharya et al 1997)

    • the essential feature of hypomotor seizures is arrest of behavior

    • a special term developed for those situations when it is not possible to figure out if the arrest of behavior is an indication of • a subjective feeling

    • impared awareness

    • hypokinesia

  • Hamer et al 1999: video-EEG verified seizure semiology in < 3 y olds

  • Hypomotor seizures

    • special features in the very young:

    • poor co-operation and verbal ablities and difficulty to test

    • maturation of the brain influences the symptom pattern in

    young children (Nordli 2013 review)

    • simple motor symptoms are typical

    • more complex fine motor symptoms appear by age

    • some of the lateralizing signs are seen less frequently

  • Fogarasi et al 2006

  • Hypomotor seizures

    • arrest of behavior is the essential feature but subtle additional

    features are seen (apnea, autonomic symptoms, eye deviation, head


    • hypomotor onset maybe followed by motor symptoms

  • Case Aapo - a boy with szs from age 1 years

    • Aapo was born fullterm, normal birth, no perinatal complications

    • Aapo has two sisters, his early development was normal, a little slower in comparison to his sisters

    • 1. seizure at the age of 1 y • from awake, arrest of behavior, tremor

  • • after the first seizure the sz situation soon escalated → clusters of daily seizures • arrest of behavior, smiling, drooling, large pupils • sometimes eye deviation to the right or up, upper

    arms may be stiff but not tonic, no consistent asymmetry

  • Vaca et al 2018

    Seizure classification – hypomotor seizures are most often focal seizures

  • Seizure classification based only on the clinical symptoms

    The main feature = arrest of behavior

    Long evolving seizures

    Subjective symptoms?

    Aware/not aware?



  • EEG • interictal EEG – normal background, no epileptic activity

    • ictal EEG – discharge in the midline Cz,Pz→ spreading bilaterally, slow discharge R>L

    • → Focal onset nonmotor seizures, awareness not known

  • Clinical onset

  • Etiology?

    • hypomotor seizures are

    seen in both benign genetic

    epilepsies, severe infantile

    encephalopaties and in focal

    structural epilepsies

    Källén et al 2002

  • How about Aapo?

    • Genetic etiology? • Benign focal epilepsy of infancy?

    • normal background • clusters of seizures • normal development and status

    • Other genetic? • No gene investigations were


    • Structural etiology? • MRI at the age of 1 year 1 month was

    considered normal

  • Treatment and development

    • valproate

    • valproate + oxcarbazepine

    • valproate + clobazame

    • valproate +lamotrigine → infrequent seizures

    • mild developmental delay, no clear epileptic encephalopathy

    • → follow-up, no further investigations

    • → a new MRI in the future was planned

  • If the seizures would have continued as drug resistant ? A surgical candidate? Localization?

    • hypomotor seizures are not specific for a certain lobe

    • frequent both in temporal, posterior and frontal lobe epilepsies (Källen et al 2002, Fogarasi et al 2003, Vendrame et al 2011)

    Källén et al 2002

  • If the seizures would have continued as drug resistant? A surgical candidate? Localization?

    • subtle semiological features: • long seizures

    • smiling

    • drooling, pallor

    • subtle eye movements

    • no consistent lateralizing signs

    • ictal EEG localizing CPmidline, side R>L

  • How could we proceed?

    • →FDG-PET

    • →new MRI

    • →genetic investigations

    • Stereo-EEG?

  • What happened later?

  • The etiology is revealed

    • Aapos older sister started to have seizures→ diagnosis of tuberosis sclerosis

    • also Aapos father was diagnosed with TSC

    • re-evaluation of Aapos MRI → one subependymal nodule, no clear tubers→ TSC diagnosis

  • New MRI at the age of 6 years: Several small tubers bilaterally

  • New referral

    • frequent drug resistant seizures

    • behavioral problems aggravated by AEDs

    • mild learning disability

    • seizures have similar features as before

    • EEG different, LP focus

  • More information on seizure semiology

    • at the age of 6 years

    • arrest of behavior, peculiar smile or laughter, eyes wide open, wandering eye movements

    • may fall, occasionally rightsided clonias

    • testing: aware in the beginning of the seizure

  • More detailed information on seizure semiology

    • at the age of 9 years

    • describes visual symptoms: bright transparent light in the middle with spreading dark lines around

  • Clinical onset (at 9 years of age)

  • Deepest hypometabolism in the left parietal tuber

  • What happened later?

    • Sz classification: Focal onset visual aware seizures

    • Localization: Interictal and ictal EEG, FDG-PET → L parietal tuber

    • Resection of the L P tuber with intraoperative intracranial recording

    • Outcome: seizure free for 10 months after which the seizures reappeared, the visual symptom is a bit different from the preoperative

    • Primary/additional focus on the other side? Complexity typical for TSC?

  • Conclusions –hypomotor seizures

    • children are not small adults • special semiological features

    • special features as patients

    • hypomotor seizures are seen in several different epilepsy types and etiologies –not specific

    • useful term for the clinical work

    • subtle semiological features, EEG and imaging help in localization, genetic studies

    • new information by time

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