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EEG

Should EEG be obtained?

Author, date, country, and industry of funding Patient Group Strength of Evidence (GRADE) Research design Significant results Limitations

(Arthur et al., 2008)

USA

Children age 6-14 years

N= 150

(349 were recruited)

Single afebrile seizure followed up at 9, 11 and 27 months.

Provider decided who got MRI

 

Low

Prospective cohort

Followed for at least 27 months

Children with absence, myoclonic or prior unrecognized seizure were excluded.

There was a recurrence rate of 66.4%

An abnormal EEG had no association with seizure recurrence at 9, 18, or 27 mo (p = 0.1806, p = 0.2792, and         p =0.2379, respectively)

 

Recur By (%)

9 mo

18 mo

27 mo

Normal EEG n=55

50.9

56.4

60

Abnl EEG

 n= 95

62.1

65.3

69.5

Normal MRI

n=87

59.8

65.5

67.8

Non signif. MRI

n=18

33.3

33.3

44.4

Signif. MRI

n= 20

80

80

80

A “significant” MRI abnormality (16% of subjects) was associated with increased risk of recurrence at 9 mo (p = 0.0389), but not 18 or 27 months

They do not recommend MRI after first seizure, because it is not predictive.

Of the 349 recruited into the larger study, 189 subjects met the criteria for this study.

150 had EEG performed

125 subjects had MRI performed.

 

 

(Chan et al., 2010)

Singapore

Children aged 1 month to 15 years with first  afebrile seizure

108 with ≥ 2 afebrile seizure and 103 with first afebrile seizure

Very Low

Population Survey

 

1st SZ

Epilepsy≥ 2 SZ

P value

Develop- mental exam (normal)

93%

87%

P=0.046

Neuro exam (normal)

98%

92%

P=0.016

EEG (abnl)

36.9%

75%

P≤0.005

CT/MRI (abnl)

33%

20.3%

NR

 

 

Population based study that looked at the epidemiology of afebrile seizure.

(Anand et al., 2012)

United Kingdom

128 children mean age 6.5 years (range 1 month to 17 years.

Very Low

Appears to be an abstract only

 

Retrospective observational cohort

 

Video EEG (vEEG) was normal in 75 subjects (59%)

Non-epileptic events were recorded in 8 subjects (6%)

Idiopathic generalized epilepsy was diagnosed in 14 subjects (11%)

Generalized epilepsy with febrile seizure was diagnosed in 2 subjects (2%)

A focal epilepsy was diagnosed in 29 subjects (23%)

Sensitivity= 100

Specificity = 10

(+) predictive value = 85%

(-) predictive value= not estimable

34 subjects had neurodevelopmental problem, 11 subjects had a family history of epilepsy, and 13 had a history of febrile seizure.

(Hamiwka, Singh, Niosi, & Wirrell, 2007)

Children 1 month -17 years

Mean age- 8 years, =/- 5 years

N= 127

53% male

Seen in clinic 52 +/- 18 days after first encounter

Development delay present in 19 children (15%)

Abnormal neurological exam was present in 14 (11%)

Very Low

Non randomized prospective cohort study of children seen at a First Seizure Follow-up Clinic

24% events were felt to be non-epileptic (n= 31) Primary event was syncope

74% were felt to be epileptic (n=94)

2% (2) were unclassifiable

 

Results of follow up EEG

All 94 children with an epileptic event had an EEG. 44 of these children (47%) had abnormalities present, 53% did not.

Thirty children without an epileptic event had EEGs. 93% had normal studies.

Over a one year follow up, 42 children (45%) were diagnosed with epilepsy.

 

 

Many of the subjects (38%) in this study did indeed have a prior seizure event that was unreported by the referring provider, or unrecognized by the parent/caregiver at the time of the referral.

(Hsieh et al., 2010)

USA

317 infant subjects (range 1-24 months) urban population

Low It is a cohort study based on a clinical guideline.

Prospective cohort

EEG (all subjects) abnormalities were found in half

CT (298/317 obtained) abnormalities were found in a third

MRI (182/ 317 obtained) abnormalities were found in 57%

Of the 193 normal CTs, 97 underwent MRI of which 32 (33%) had an abnormal MRI

The majority had more than one seizure upon presentation.

The incidence of seizures lasting longer than 20 minutes was 8.5%

30 subjects had a history of prematurity.

Increased likelihood of obtaining an MRI in younger infants.

 

(Landau, Waisman, & Shuper, 2010)

Israel

85 subjects average age 7.5 y (range 0-18 y) who made 104 visits to the ED

Excluded febrile seizure or other primary diagnosis

Very Low- inconsistent includes subjects that do not apply to this guideline

Retrospective chart review

Laboratory tests were obtained in 84% of visits. Eight percent provided useful information and < 5% were helpful in diagnosis and management.

Only one lumbar puncture was performed.

Eight percent of visits had electrocardiography performed and all were normal

Seven percent of visit had electroencephalography performed and was consistently useful and was always performed along with a neurology consultation

Mix of children with first seizure and those already on medication for seizure. Only 30 (35% )subjects presented with first seizure

These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time. It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.