EEG Benign Variants

Question 1

Answer 1

Midline theta rhythm of drowsiness (Ciganek)

• Drowsiness
• Most prominent in central vertex
• 5-7 Hz smooth, sinusoidal, arciform, spikey or mu-like

Question 2

Answer 2

Wicket Spikes

• 6-11 Hz
• Temporal
• Unilateral/bilateral
• Medium-high amplitude
• Older adults
• Drowsy/light sleep
• Arciform/wicket-like appearance

Question 3

Answer 3

RMTTD (Psychomotor variant)

• Theta
• Midtemporal
• Unilateral/bilateral
• Does not evolve or spread to other sites
• 5-15 seconds duration
• Wake (less during drowsiness and disappears during light NREM sleep) (? Research this)
• Teen/adult

Question 4

Answer 4

Small sharp spikes

Beneign sporadic sleep spikes

Beneign epileptiform transients of sleep

• Drowsiness or light sleep (disappears during deeper sleep) in adults
• Low amplitude and duration (no repetitive trains or slow waves after)
• Usually unilateral but can be b/l independent
• Temporal or broad field of distribution

Question 5

Answer 5

14 and 6 Hz Positive Spikes

• 20-60% of normal population
• 12-20 years
  
  • 6 Hz < 1 y/o
  • 14 Hz adolescents (more commonly seen)
  • Both can be seen in the same study
• Drowsiness and light sleep
• Posterior temporal and parietal
• Trains of arch shaped waveforms with alternating positive spikey components and negative smooth rounded waveform
  
  • Looks a little like a sleep spindle
  • Usually < 2 seconds
• Best seen in referential montages

Question 6

Answer 6

6 Hz Phantom Spike and Wave

• Diffuse, anterior or posterior predominant bursts
  
  • Posterior dominant: drowsiness
• Mitten-like morphology
  
  • Small spike (often not visible, i.e. phantom) followed by slow wave
  • Also phantom in that it is very brief
• Drowsiness and light sleep
• Adolescents and adults

Question 7

Answer 7

SREDA (Subclinical Rhythmic Electrographic Discharges in Adults))

• 5-6 Hz sharply contoured theta
• Diffuse but maximal over parietal and posterior temporal regions
• Seconds - 2 min (usually > 30 seconds)
• Drowsiness
• Usually abrupt onset and termination
• Hyperventilation can trigger
• Older adults (usually > 50 y/o)

Question 8

If a patient is aroused from N1 sleep and the posterior alpha activity reappears with a higher amplitude then the individuals regular rhythm it is called ________

Answer 8

Paradoxical alpha

Question 9

What is the rhythm?

Answer 9

Mu

• Alpha rhythm
• Represents sensory-motor cortex at rest
• Suppressed by contralateral opening and closing fist (or thinking about it)
• Non reactive to blink/eye closure
• Awake only
• Max central

Question 10

What 2 wave forms do you see?

Answer 10

Lambda waves (mu later on)

• Occipital region
• Surface positive (actually negative?)
• Triangular in shape and generally symmetric
• Looks like POSTS (except with lambda the patient is awake)
• Brought out by scanning of a textured image

Question 11

What are the benign variants that occur during drowsiness?

Answer 11

WoRMS 6 or 14?

• Wicket Spikes
• RMTTD (psychomotor variant)
• Midline Theta Rhythm of Drowsiness (ciganek)
• SREDA (Subclinical Rhythmic Electrographic Discharges in adults)
• 6 Hz phantom spike and wave
• 14 and 6 Hz Positive Spikes

Question 12

All are drowsy but what is speical about:

Wicket Spikes

Answer 12

• 6-11 Hz temporal
• Older adults

Question 13

All are drowsy but what is speical about:

RMTD (Psychomotor)

Answer 13

• Temporal
• Teen/adult

Question 14

All are drowsy but what is speical about:

Midline theta rhythm of drowsiness (ciganek)?

Answer 14

• Central/vertex

Question 15

All are drowsy but what is speical about:

SREDA?

Answer 15

• Parietal/posterior temporal
• 5-6 Hz sharply contoured theta
• Older adults
• Hyperventilation trigger
• Usually abrupt onset and termination
• Usually > 30 seconds

Question 16

All are drowsy but what is speical about:

6 Hz spike and wave (phantom)

Answer 16

• Posterior dominant
• Small spike
• Brief duration

Question 17

All are drowsy but what is special about:

14 and 6 Hz Positive bursts

Answer 17

• Looks like sleep spindle
• < 2 seconds
• Posterior temporal/parietal
• Young adults

Question 18

What are the 2 benign variants seen in older adults (> 50)?

Answer 18

• Wicket spikes
• SREDA

Question 19

Diagnosis?

Answer 19

Ocular flutter

Eye may or may not be open

Question 20

Answer 20

Posterior slow waves of youth

Typically seen ages 6 to 12

Question 21

Diagnosis?

Answer 21

Glossokinetic artifact.

Question 22

Diagnosis?

Answer 22

Lambda waves

Question 23

Diagnosis?

Answer 23

Eye rubbing artifact

Question 24

Diagnosis?

Answer 24

Question 25

Diagnosis?

Answer 25

These are 6 Hz

Question 26

Diagnosis?

Answer 26

Question 27

Diagnosis?

Answer 27

Tremor artifact | (Lots of muscle as well)