Neuropsychology of Epilepsy II

1
Birmingham 2006

• Neuropsychology of Epilepsy II
• Pam Thompson
• Department of Clinical Experimental Epilepsy,
• Institute of Neurology
• National Society for Epilepsy

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Surgical treatment

• temporal lobe surgery
• most common most successful
• NHNN experience
• 1988 programme began
• neuropsychological assessment part of
  pre-surgical work-up
• MRI, EEG, Psychiatry
• 31/12/2005 N 360 cases

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Surgical treatment

• Why assess?
• prognostic data
• good concordance between investigations good
  prognosis for seizure control
• provides data to counsel patients
• flags up cases at risk of major cognitive
  decline

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Surgical treatment

• Historical background
• 1940s 1950s bilateral temporal lobectomies
• 40 published cases
• Scoville no marked changes with the exception
  of a very grave,recent memory loss so severe as
  to prevent our patient (HM) from remembering the
  names of his close associates or even the way to
  the toilet
• 48 years amnesic

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Surgical treatment

• Historical background
• unilateral temporal lobectomy cases
• NT RTL epileptogenic focus on EEG
• 1961 RTLR
• Surgical specimen normal
• Profoundly amnesic
• 1986 diedpost-mortem LHS

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Surgical treatment

• Neuropsychological assessment
• detailed assessmentemphasis on memory
• subjective ratings of everyday problems
• FU 3-6 ms 1-2 yrs
• existing FU data regularly analysed
• used in pre-op counselling
• sodium amytal procedure (WADA)
• routinely 1988-1995
• selectively 1995-2004
• rarely 2005 -

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Temporal lobe surgery
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cases showing change in verbal learning score _at_
one year.
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Predicting decline

• Significant
• left sided
• good verbal memory
• age gt 40yrs
• additional pathology
• Not significant
• Age of onset epilepsy
• duration
• Verbal IQ

Seizure control?
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N cases showing decline in verbal learning score
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Intracarotid Sodium Amytal Test

• Gardner 1941
• temporary inactivation of language zone
• procaine hydrochloride via trephine hole
• 1949 Wada sodium amobarbital
• 1960 first series published N20
• direct into common carotid
• 1962 for memory assessment

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Intracarotid Sodium Amytal Test

• 1. To establish language dominance
• 95 RH left dominant
• 80 genetic LH left dominant
• rates of atypical dominance elevated in PWE
• LH 69 left 18 right 13 both
• Why important
• decision to operate
  
• size of resection
• type of operation
• 2. To screen for amnesia

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Intra-carotid Sodium Amytal Test

• ipsilateral
  contralateral

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Procedure

• 2-3 pictures
• Injection incremental until hemi-paresis
• Present 8 objects for naming
• Test memory for 4 objects
• Test memory pre-injection items
• Upon recovery test for remaining 4 objects

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Procedure

• both sides in turn
• ipsilateral side first
• EEG monitored throughout
• video monitoring
• dosage 45mg-625mg
• mode 100mg
• duration 1.5-14 mins

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Procedure

• 1988-1995
• all cases
• 1995-2004
• selected cases
• discordant data

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Problems

• invasive, 1 in 200 morbidity
• psychologically stressful
• labour intensive (min n 7)
• costlywagesstay in hospital
• procedural failures
• X flow FLs visual neglectsedation
• testing window small

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Sodium amytalFailures

• SH
• lhs
• verbal memory impaired visual intact
• amytal not indicated but failed at another centre
  
• amytal 8/2002 failed
• super selective passed 11/2002
• LTLBR may 2003
• post-op 2/12 sz free 1/m for 5/12 sz free 2004
• not amnesic
• Verbal memory decline (as predicted)

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Sodium amytalFailure

• PM
• rhs
• visual memory ? verbal memory intact
  
• failed amytal at another centre
• RTLBx 004/05
• sz free not amnesic
• 6/12 memory no change from pre-op

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Sodium amytalPass

• AS 54 yrs AO 24 yrs
• EEG RT focus
• amytal at another centre- pass
• 1993 RTLBR post-operative cognitive decline
  odd behaviours
• Seizure control deteriorated
• Post-op MRI LHS
• Highly dependent after 10yrs wife unable to cope
• Moved to residential care for EMI

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Sodium amytal test

• not valid as screen for amnesia
• no cases have become amnesic without abnormal
  
• imaging

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Sodium amytal test

• not valid as screen for amnesia
• no cases have become amnesic without abnormal
  
• imaging
• in cases with clear unilateral pathology IAP is
  a screening test for a patient that does not
  exist
• patients with bilateral pathology are _at_ risk
• regardless of amytal outcome?

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fMRI as alternative

• enables observation of brain activity during
  cognition
• non-invasive
• less labour intensive
• cheaper (if you have access to a scanner!)
• regard
• good evidence for language lateralisation
• Some evidence for memory
• Any better at predicting meaningful change than
  predictions from other existing data

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Intracarotid Sodium Amytal Test

• 1. language lateralisation
• 2. screen for amnesia
• 3. prediction of memory decline
• 4. lateralisation of seizure focus
• 5. prediction of seizure control

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Intracarotid Sodium Amytal Test

• 3. prediction of memory decline
• baseline neuropsychological data ,demographic
  scan data
• amytal data does not improve the accuracy of our
  model
• other centres show statistical but not clinical
  significance
• insufficient evidence of continued use of
  invasive, costly and psychologically stressful
  technique