Cumulative Cognitive Deficits and Electroconvulsive
Therapy
Hazel Ballard - [email protected]
Mentored by Professor George Kirov
Introduction
The induction of seizures through short term Electroconvulsive Therapy
(ECT) is a widely accepted and effective method for the treatment of
severe acute depression. It is said to be one of the safest treatments
implemented in psychiatric practice, however little is known as to the side
effects of long term maintenance ECT, and one of the major concerns is
that it could lead to progressing cognitive deficits.
Aim
We used a linear regression model with random effects and fixed effects to
analyse our data. Recorded in table 2 are the P values of each variable
found to be significant (at a significance level of 5%). Figure 2 shows the
correlation found between Trail B and some of the co-variates recorded.
Digit !
Span
Memory!
Fluency! MMSE!
Complex
Figure
CFQ
Reaction
Trail A
Trail B
460
455
479
384
360
418
340
332
HAMD
0.03
0.0006
9×10
0.0007
0.002
0.003
Age
0.005
6×10
0.005
-8×10
4×10
4×10
3×10
0.0003
0.07
No. of
Assessments
The aim of this study was to find out whether individuals undergoing long
term ECT had any progressive decline in cognition.
Method
To obtain a conclusion we measured the number of
ECT’s a patient had and looked for a correlation
between this and their performance on cognitive
tests. Nine assessments were used (as shown in
figure 1) over a period of 10 years, and four covariables were recorded (age, HAMD score, days
since last ECT and how many times they had
Figure 1 - An example of the Complex
practiced that test). Data was collected pre, post
Figure Test
and three months after an ECT course.
Description
Cognitive Domain
Four versions of the standard MMSE to
minimise learning.
Global cognitive functioning and
orientation.
Digit Span Backwards
Number of digit repeated backwards.
(Four Versions).
Concentration, attention and working
memory.
Trail making A
The time needed to connect 24
scattered numbers in order.
Processing speed.
Trail making B
The time needed to connect 12 numbers
and 12 letters in order.
Executive Functioning.
Reaction Time D
Computer test assessing speed of
reactions.
Processing Speed.
Recognition of Words, Shapes and
Faces
Recalling and recognising previously
learnt words, shapes and faces.
Verbal and visual episodic memory.
Complex Figure Immediate Recall
Complex figures to be drawn from
memory. (Four versions).
Visual episodic memory and executive
functioning.
Verbal Fluency Test
Number of words named beginning with
a given letter within one minute. (Four
versions).
Executive function and Linguistic ability.
CFQ
Self assessment on a series of 25
statements.
Subjective assessment of memory and
cognitive performance.
Mini Mental State Examination
Conclusion
Results
493
No. ECTs
Days since
ECT
0.002
Practice
10
8×10
0.006
0.04
0.006
0.07
Table 2 - P values of each test vs co-variates
References
Semkovska.M and McLoughlin.D.M. (2010). Objective
Cognitive Performance Associated with Electroconvulsive
Therapy for Depression: A Systematic Review and MetaAnalysis. Biological Psychiatry. 68 (1), 568-577.!
Acknowledgments
I would like to thank CUROP for sponsoring this
programme. Special thanks to Professor Kirov and the rest
of the team at Whitchurch Hospital ECT Suite for their
support and teaching. Thank you also to all the patients who
agreed to undergo tests during their treatments.
Figure 2 - Scatter plots to show the correlations found between Trail B and the co-variates measured
Table 1 - Descriptions of each cognitive test used (Semkovska et al 2010)
We can conclude that our results showed a lack of
cumulative cognitive deterioration with an increasing
number of treatments. This is shown in table 2, as there
was no significant relationship between the number of
ECTs and any of the cognitive tests used. This is also
demonstrated in Figure 2, as the R squared value
referring to number of ECTs vs Trail B Time has a value of
0.00003, suggesting there is no significant correlation
between the two.
The fear of cognitive
decline and memory
problems is one of the
biggest deterrents to
patients offered long term
ECT, however we have
Figure 3 - Whitchurch Hospital
found that co-variates,
such as age and HAMD score, have been a lot more
influential than treatment number. We have found that
discussing our findings with patients undergoing ECT can be
very reassuring, as they are able to see how stable their
scores are throughout. Our results suggest that patients
can have long-term treatment, without worrying about
long-term cognitive consequences.