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Neuropsychology of Epilepsy II

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Title: 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


2
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

3
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

4
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

5
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

6
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 -

7
Temporal lobe surgery
8
cases showing change in verbal learning score _at_
one year.
9
Predicting decline
  • Significant
  • left sided
  • good verbal memory
  • age gt 40yrs
  • additional pathology
  • Not significant
  • Age of onset epilepsy
  • duration
  • Verbal IQ

Seizure control?
10
N cases showing decline in verbal learning score
11
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

12
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

13
Intra-carotid Sodium Amytal Test
  • ipsilateral
    contralateral

14
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

15
Procedure
  • both sides in turn
  • ipsilateral side first
  • EEG monitored throughout
  • video monitoring
  • dosage 45mg-625mg
  • mode 100mg
  • duration 1.5-14 mins

16
Procedure
  • 1988-1995
  • all cases
  • 1995-2004
  • selected cases
  • discordant data

17
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

18
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)

19
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

20
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

21
Sodium amytal test
  • not valid as screen for amnesia
  • no cases have become amnesic without abnormal
  • imaging

22
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?

23
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

24
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

25
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
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