| EEG pattern in common epileptic seizures | ||||
| Seizure type | Semiology | Ictal EEG | Ictal EMG (both deltoids) | Comments |
| Generalized tonic-clonic | Stiffening → vibration → rapid face and limb twitching → slowing in jerk rate → stupor after 1-1 1/2 minutes | Massive generalized EMG obscures very fast spikes → decelerating generalized spike and wave (S/W) | Generalized high-voltage continuous | Mature seizure type of older children and adolescents. 'Generalized tonic-clonic' is much misused for any infantile convulsion |
| Clonic | Rhythmic or semi-rhythmic or syncopated jerks | Generalized rhythmic or semi-rhythmic S/W | Semi-rhythmic accentuations | Many infantile convulsions including anoxic epileptic seizures (AES) |
| Hemiclonic | Unilateral semi-rhythmic | Contralateral semi-rhythmic S/W | Contralateral semi-rhythmic accentuations | Many infantile convulsions including anoxic epileptic seizures (AES) |
| Absence (sudden-onset blank 10s or more duration) | Maybe rhythmic small jerks eyelids or neck | 3/s generalized S/W | None | Inducible by hyperventilation |
| Myoclonic-absence | Upper limbs slowly elevate with rhythmic jerks of shoulders | Generalized 3/s S/W | Incremental tonic activity, superimposed 3/s high-voltage transients | Surface EMG (as bilateral deltoid) is a necessary part of EEG examination |
| Myoclonic | Isolated clustered or rhythmic jerks | Polyspike-wave or irregular spike/polyspike-wave | Spike-like 10-100ms bursts singly or in groups | Seen in many epileptic syndromes and situations |
| Negative myoclonic (atonic/astatic) | Jerk/drop, singly or clustered | Polyspike followed by a high-amplitude slow wave | Ongoing EMG disappears during drop | Video may add |
| Spasm | Longer than myoclonus, usually in runs | Serial biphasic slow complexes with superimposed fast (beta) often central and time-locked with spasms | Diamond or rhomboidal bursts of 0.5-2s duration | Hypsarrhythmia but not always; also seen in older children |
| Tonic | Several seconds stiffening, agonists and antagonists | Flattening or attenuation of background with superimposed low-voltage fast activity and loss of previously seen interictal discharges | High-voltage continuous ('fuzz') | Seen in severe epilepsies as Lennox-Gastaut syndrome |
| Partial/focal/ localization-related | Any site, any semiology | Localized/lateralized morphology varies with age, ± secondarily generalized | Depends on site of origin | Seen in genetic ('idiopathic') and structural epilepies |
| Epileptic syndromes | ||||||
| Epileptic syndrome | Age of onset | Age of offset | Clinical | Interictal EEG | Ictal EEG | Additional investigation |
| Epileptic encephalopathy with suppression bursts | Prenatal, day 1, first weeks | Not unless abolished by pyridoxine or pryridoxal phosphate | Spasms, jerks; profound delay if untreated | Suppression-burst | Bursts | Pyridoxal phosphate trial or pyridoxine trial if pyridoxal phosphate not available, urine α-AASA, CSF amino acids, copper, copper oxidase, catecholamines, brain MRI, ARX, STXBP1 |
| Hemifacial spasms | Day 1 (but may be later) | Only if surgery | Exceedingly frequent facial contractions with winking, eye movement, autonomic disturbance | Normal | Normal except for eyelid movement artefact | Brain MRI, ictal SPECT (hamartoma of floor of fourth ventricle with neuronal elements on surgery) |
| Gelastic/dacrystic seizures | Day 1 (more often later) | Only if surgery | Exceedingly frequent brief bouts of laughter → crying, autonomic. Behavioural arrest if untreated | Often normal | May be normal | Audio with video, MRI including sagittal T2, ictal SPECT (hypothalamic hamartoma on surgery) |
| Neonatal tonic-clonic seizures | First week | Uncertain | Tonic-clonic or tonic-myoelonic seizures with posturing → focal or multifocal clonic | 'Abnormal' | Flattening → focal or bilateral discharges | Pyridoxal phosphate or pyridoxine trial, urine α-AASA, KCNQ2 mutations |
| Benign neonatal-infantile seizures | Neonate-3mo | <1y | Convulsive, often clusters ± head and eye deviation | Normal or maybe spikes in sleep | Lateralized then generalization | Mutations in SCN2A (diagnosis at 3mo avoids bad prognosis) |
| CDKL5-related epilepsy | 4w (1-10w) | ?? Not usually | Stares, flush, tonic ± → clonic; → frequent spasms; ± Rett-like | ± Normal | Flattening | Mutations in CDKL5 |
| DEND (delay, epilepsy, neonatal diabetes mellitus) | 3mo | ? | Neonatal diabetes mellitus, West syndrome with spasms | Independent spikes | ? | Sulphonylurea-responsive mutations in Kir6.2 (potassium ATP channel) |
| Malignant migrating partial seizures | 40d (neonate -3mo) | ? Never | Partial, autonomic, vary from seizure to seizure, appear with increasing frequency over time | Normal to slow, multifocal sharp | Independent R + L sharp runs in theta or alpha frequency | Candidate for novel investigations |
| GLUT1 deficiency (glucose transporter deficiency without full DeVivo syndrome) | ~3-6mo (more data needed) | If given ketogenic diet | Early absences, myoclonic episodes before feeds | Often focal spikes in infancy, generalized S/W in older children (like idiopathic generalized epilepsy) | S/W runs | Fasting blood and CSF glucose + lactate. SLCA1 mutation |
| West syndrome (serial epileptic spasms, regression) | 5mo (4-7mo) | Various | Spasm runs with loss of contact and regression - many possible associations, e.g. Down syndrome | Hypsarrhyth-mia usually | Runs of spasms | MRI, karyotype, 1p36 ARX, CDKLS, SCN1A, rarely metabolic, incl. D-bifunctional protein defect |
| Benign familial infantile seizures (BFIS)/benign partial epilepsy of infancy | 5-6mo (3-18mo) | <2y | Clusters of brief seizures with loss of contact, motor arrest ± head and eye deviation, some automatisms ± secondary generalization; normal development; ± → paroxysmal kinesigenic dyskinesia | Normal | Fast spikes in various locations ± → generalized S/W | No additional investigations required |
| Benign myoclonic epilepsy of infancy | 6mo | Usually 6mo-5y after | Jerks without falls singly or in clusters; may have later generalized tonic-clonic seizures in adolescence | Normal | Generalized polyspike and wave | None (but not known if might be GLUT1D manifestation) |
| Reflex myoclonic epilepsy of infancy | 6-21 mo | Within 4-14mo | Run of a few myoclonic jerks if startled as with a tap on the head | Normal | Generalized S/W | None |
| Angelman syndrome | 9mo | ~Never | Seizure onset before Angelman features obvious (median age at diagnosis 60mo); absences, myoclonic | Spike on sharp wave on passive eye closure, frontal slow runs, theta | Various S/W runs | Emphasizes importance of passive eye closure during EEG and at least brief video in all EEG recordings |
| Dravet syndrome [including severe myoclonic epilepsy in infancy (SMEI) and SMEI-borderline] | 3-12mo (<18mo) | No | Long especially hemiclonic febrile seizures, clonic, tonic-clonic later ± myoclonic | Normal early ± photosensitivity, background slows with age | Polyspike-wave, generalized S/W, focal discharges | Mutations in SCN1A and less often in PCDH19 |
| Febrile seizures (FS) | 3mo - <6y | <6y | Wot rigor febrile syncope, 'breath-holding spell', reflex asystolic syncope; temperature >38°C (101°F) probably clonic or tonic | Normal, later ± hypnagogic S/W. age 3-4y | Very rarely captured | Investigations for infections, etc. . Brain MRI not required |
| Febrile seizures plus 05*) | FS <3mo or="">6y | ? | ± Afebrile epileptic seizures. NB genetic epilepsy with FS+ (GEFS+) is not a patient diagnosis but is a family one | Usually normal | Not known | Not MRI. SCN1A or other mutation possible |
| Febrile status epilepticus (FSE) | Median 1.3y (interquartile range 0.99-2.2y) | ? | Median duration 68min. Semiology disputed but includes clonic | Probably normal | Prolonged discharges | Brain MRI normally not required unless suspect encephalitis |
| Benign convulsions with mild gastroenteritis | Median 23mo with rotavirus | After illness | Asian, especially Japanese clusters within 5d of gastroenteritis | Not known | Not known | Viral studies especially rotavirus |
| Benign focal epilepsy in infancy with midline S/W during sleep | T7mo (4-30mo) | 26mo | Cyanosis (especially perioral), stare, behavioural arrest, not secondary generalization postictal sleep (most don't need therapy) | In sleep vertex (midline) spike and bell-shaped wave | Vertex theta runs | None |
| Late-onset 'juvenile spasms' | >12mo | ? Never | Cryptogenic or structural, e.g. double cortex/subcortical band heterotopia | Varied | Runs of serial complexes: slow + fast superimposed | Brain MRI |
| Myoclonic-astatic epilepsy | 18-50mo | ?36-100mo | Tonic-clonic, myoclonic-astatic, myoclonic, + myoclonic status, no tonic seizures, may remit | S/W on falling asleep | Generalized S/W bursts with special EMG features: EMG burst → EMG loss | Brain MRI commonly normal (in severe learning disability consider MECP2 duplication by MLPA) |
| Lennox-Gastaut syndrome | 3-5y | ? Never | Axial tonic in sleep, atypical absences; learning disability; cryptogenic and symptomatic; nonconvulsive status epilepticus common | Slow background, slow S/W awake, high-voltage 10-l2Hz in sleep | Flattening with tonic EMG | Brain MRI and possibly other aetiological investigations as not a single-cause diagnosis |
| Panayiotopoulos syndrome | 3-6y(l-10y) | Usually within 2y | ± From sleep: ictus emeticus (epileptic seizure with nausea and vomiting at onset) pallor and other autonomic features, eye deviation, flaccidity, ± >30min duration then called autonomic status epilepticus | Spikes may be occipital but other sites, such as rolandic, more likely to be seen in sleep. ± Fixation-off sensitivity with occipital discharges | Spike runs occipital but from other sites; may be cardiorespiratory arrest | Panayiotopoulos syndrome diagnosis prevents many other investigations. Brain MRI only if not certain about neurodevelopmental normality at time of first episode |
| Landau-Kleffner syndrome. Continuous spike-wave in sleep 1CSWS) also called ESES (epileptic status epilepticus in sleep) | 2-8y | Varied | Auditory agnosia, cognitive decline; learning difficulties may overshadow subtle epileptic seizures if present. Decline in abilities of a child with shunted hydrocephalus may be due to unrecognized CSWS | Perisylvian spike complexes slow spike-wave in non-REM sleep = CSWS | Various | Brain MRI often done; place of functional imaging uncertain |
| Ring chromosome 20 | 4-8y(day1-17y) | ? | Most have normal development before seizure onset, typical episodes of terror and hallucination may not begin till after age 4y. Neurobehavioural decline with seizures, potentially reversible | Prominent rhythmic frontal slow (delta, but also theta) ± spikes - may not be seen in early years | Frontal onset discharges | Chromosome karyotype with request to count 200 mitoses |
| Childhood absence epilepsy (CAE) | Peak 5-6y (4-10y) | 2-6y after onset | Pure sudden on and sudden off blanks, usually hyperventilation-induced | Normal, not photosensitive + occipital intermittent rhythmic delta activity | Symptomatic bursts of 3/s S/W with one spike per wave, often 10s or more absences | Video during hyperventilation in clinic may suffice, but ictal EEG with video best in case pseudo-epileptic absences. If atypical and food (meal) related consider GLUT1 deficiency |
| Childhood absence epilepsy with photoparoxysmal response | 4-10y | ? As CAE | As for CAE except photoparoxysmal response on EEG | Normal but generalized spike/ polyspike and wave on stroboscopic activation | Symptomatic bursts of 3/s S/W with one spike per wave | Video during hyperventialtion in clinic may suffice, but ictal EEG with video best in case pseudo-epileptic absences. If atypical and food (meal) related consider GLUT1 deficiency |
| Epilepsy with myoclonic absences | 7y11-12y) | May not | Upper limbs slowly elevate with 3/s jerks | Normal background ± generalized S/W bursts | 3/s S/W with incremental tonic EMG and superimposed 3/s EMG bursts | Video. Consider GLUT1 deficiency and chromosomes (e.g. trisomy 12p) |
| Benign rolandic epilepsy (BRE)/ benign epilepsy with centra-temporal spikes (BECTS) | 7-8y(4-14y) | Within 2-4y of onset (<16y) | Hemifacial-salivatory often from sleep, family holiday in back of car; secondary generalization common | Rolandic or centro-temporal spike complexes | Focal discharge during episodes | No need for brain MRI if history typical and neurologically normal. Rolandic spikes more common in those without epilepsy |
| Childhood occipital epilepsy of Gaslsul | 8y(3-15y) | 50% within 2-3y | Seizures ~frequent and diurnal, elementary visual hallucinations: multicoloured circular patterns may be the sole manifestation. Migrainelike | ± Fixation-off sensitivity with occipital discharges | Sudden onset of fast rhythms, fast spikes or both in occipital regions | Brain MRI desirable in case symptomatic. Consider P0LG1 if suggestion of mitochondrial disorder |
| Autosomal dominant nocturnal frontal lobe epilepsy | Mainly 8-14y | May not | From sleep, with several throughout the night (contrast night terrors, 1 or 2 at beginning of sleep) | Normal | Often normal with only ictal EMG and motion artefacts | Nocturnal video preferably with infrared recording; helpful to get night-time video of close or distant family members who may be affected; gene analysis by arrangement |
| Juvenile myoclonic epilepsy | 9-13y (5-20y) | May not | Morning myoclonus, clumsiness, generalized tonic-clonic and clonic-tonic-clonic seizures especially when sleep deprived. In childhood, short absences may precede onset of myoclonus and tonic-clonic seizures | Irregular spike and polyspike wave bursts | 4-6/s polyspike and wave. Absences may have multiple spikes per wave, often <10s, shorter than in CAE | Investigations generally unhelpful (if regression, consider progressive myoclonus epilepsies ) |
| Mesial temporal lobe epilepsy with | 4-16y | Mostly only if surgical | Ascending epigastric aura may be fear or panic, deja vu, | Spike and slow | Subtle onset with focal | High quality brain MRI targeted to show hippocampi |
| hippocampal sclerosis | resection | dreamy state, oro-elementary automatisms, etc. | complexes in ipsilateral anterior temporal region | crescendo theta | ||
Source:
Mary D. King, 2009. A Handbook of Neurological Investigations in Children. 1 Edition. Mac Keith Press.
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