Neurofeedback Peak Neurofeedback Peak PerformancePerformance

in Microsurgeryin Microsurgery

Tomas RosDept. of PsychologyGoldsmiths CollegeLondon

Conjunct COST B27 and SAN Scientific Meeting, Swansea, UK, 16-18 September 2006

Neurofeedback Peak Neurofeedback Peak PerformancePerformance

in Microsurgeryin Microsurgery

Tomas RosDept. of PsychologyGoldsmiths CollegeLondon

RationaleRationale• EEG peak-performance enhancements in:

cognition sport artistic ability

• microsurgical technique uniquely combines the mental and physical skills present in such fields

• we assessed the training effects of 2 widespread neurofeedback protocols to the novel area of

eye microsurgery

2 Protocols

Research Evidence:

• SMR-Theta training can lead to improvements in attention and memory (Vernon et al. 2003, Egner & Gruzelier 2004)

• Alpha-Theta has been shown to induce relaxation and reduce anxiety, as well as enhance artistry (Egner & Gruzelier 2003, Raymond et al. 2005)

Neurofeedback Training

• visual feedback• SMR, theta, high beta SMR (12-15 Hz), theta (4-7 Hz), high beta (22-30 Hz)• referential at Cz

• auditory feedback only• alpha, theta alpha (8-11 Hz), theta (4-7 Hz)• referential at Pz

Alpha-Theta:

SMR-Theta:

Neurofeedback Training

• AT alpha: babbling brook theta: ocean wave

• SMR: “Space race” (3-way)

• ProComp + amplifier• Neurocybernetics EEGer• 160 Hz sampling, 0.5 s filter• 3-min autothreshold

Equipment:

Feedback:

Neurofeedback Training

• approx. 1 session / week

• 8 sessions in TOTAL

• 3 min baseline (period 1)

• approx. 25 min session

Duration:

Rate:

Study DesignStudy Design

• randomised, single-blind, controlled

• 2 neurofeedback protocols

Alpha-Theta (AT) N=10SMR-Theta (SMR) N=10

• 1 wait-list control group N=8

TOTALN=20

• LOCATION: Western Eye Hospital, London

• 20 trainee surgeons (NHS house officers & registrars)

• 10 males, 10 females

• mean age 33.5, SD 5.12

TOTALN=20

ControlN=8

Training onlyN=12

TOTALN=20

ControlN=8

Training onlyN=12

W A I T (~2 months)

TOTALN=20

ControlN=8

Training onlyN=12

W A I T (~2 months)

ATN=4

SMRN=4

TOTALN=20

ControlN=8

Training onlyN=12

SMRN=6

ATN=6

W A I T (~2 months)

ATN=4

SMRN=4

AssessmentAssessment

1) MOOD questionnaire Spielberger’s state & trait anxiety (pre performance self-report)

2) SURGICAL performancemulti stage surgical task on artificial-eye

(~10 min video recording from two angles)

3) ATTENTION test‘Attention Network Test’, or ANT

(15 min reaction time test on computer)

CONTROLassessment

PREassessment

POST assessment

WAITLIST GROUP(N=8)

W A I T

N F B

TRAINING ONLYGROUP(N=12)

CONTROLassessment

PREassessment

POST assessment

TRAININGpre / post

(N=8)

W A I T

N F BTRAININGpre / post(N=12)

CONTROLpre / post

(N=8)

WAITLIST TRAINING ONLY

Test-retest intervalsTest-retest intervals

CSMRAT

140

120

100

80

60

40

20

0

tim

e (d

ays)

Error bars: +/- 1.00 SE

• One-way ANOVA: no significant differences between groups

p=0.40

RESULTSRESULTS

NFB training spectra

1 2 3 4 5 6 7 8

Session

0.96

0.98

1.00

1.02

Alpha-Theta (AT) training

AVERAGE for all AT subjects

1 2 3 4 5 6 7 8 9 10

Period

0.95

0.98

1.00

1.03

1.05

Th

eta

/ Alp

ha

rat

io

p<0.01 p<0.01

SMR-Theta training

1 2 3 4 5 6 7 8

Session

0.50

0.55

0.60

0.65

AVERAGE for all SMR subjects

1 2 3 4 5 6 7 8 9

Period

0.57

0.58

0.59

0.60

0.61

SM

R/T

het

a ra

tio

p<0.01p<0.01

RESULTSRESULTS

Surgical Technique

Judges’ ratings

• scored independently

• score averaged over 2 judges

• each judge was blind to:

presentation order

subject identity

Task description Sub-step Score

1A Design of the side port

Correct stabilization of globe opposite cornea to corneal incision

1  

Correct angle of blade parallel to iris

2  

Correct length (1/2 length of 15° blade)

3  

Correct position / meridian / regularity (just on clear corneal side of limbus)

4  

Filling AC with viscoelastic evenly

5  

1B Avoidance of complications of creating the side port

No sudden collapse of AC 1  

No injury to the iris 2  

No injury to the capsule 3  

No injury to the cornea 4  

Overall Technique

post

pre

CSMRAT

1.00

0.80

0.60

0.40

0.20

0.00

tech

nic

al s

kill

sco

re (

%)

*

• Paired Wilcoxon: significant increase in SMR group

p=0.038

p=0.26p=1.0

Task Technique

wound

knotrrhexis

phaco

sideport

CSMRAT

20

15

10

5

0

-5

tech

nic

al s

core

ch

ang

e (%

)

*

• Paired Wilcoxon: significant increase in SMR group

p=0.018

6.2 %

484437332925211713951

Video number

1.00

0.90

0.80

0.70

0.60

Ove

rall

sco

re (

%)

JUDGE B

JUDGE A

• ICC: 0.85 for SMR performances, 0.64 for ALL performances

Inter-rater reliability

RESULTSRESULTS

Performance Speed

Performance Speed

• objective data calculated from videos

OVERALL time = TASK time + PAUSE time

OVERALL time: start to finish

TASK time: spent in contact with eye

PAUSE time: spent otherwise

Overall time

CSMRAT

12

11

10

9

8

7

Mea

n t

ime

(min

)

postpre

• Paired T-test: marginal decrease in AT & SMR group

p=0.16

p=0.20

p=0.84

15 %

Task time

CSMRAT

10

9

8

7

6

5

Me

an

tim

e (

min

)postpre

*

• Paired T-test: significant decrease in SMR group

p=0.021

25 %

p=0.26p=0.90

Pause time

CSMRAT

5

4

3

2

1

me

an

tim

e (

min

)

post pre

• Paired T-test: no significant changes in groups

p=0.56p=0.50

p=0.72

Individual Tasks

phaco

knotrrhexiswound

sideport

CSMRAT

2.5

0

-2.5

-5

-7.5

tim

e c

ha

ng

e (m

in)

*

• Paired T-test: significant decrease in SMR group

p=0.018

6 %

Subjective vs objective scores

• Correlation between subjective (technique) and objective (times) performance measures

• Positive changes in overall technique were coupled to reductions in total task time (R= -0.700, p=0.036)

RESULTSRESULTS

Attention Network Test

A N T Posner et al (2002, 2004)

• measures 3 separate attentional networks (alerting, orienting, and conflict)

• based on earlier functional studies (e.g. Posner & Peterson, 1990)

Attention Network Test (A N T)

conflictorientingalerting

CSMRAT

20

10

0

-10

-20

-30

Eff

icie

ncy

ch

an

ge

( m

s )

p=0.05

p=0.095

• Paired T-test: significant orienting decrease in SMR group

25 %

RESULTSRESULTS

State & Trait Anxiety

• filled in prior to each assessment

• 2 parts:STATE anxiety

how subject feels at that moment

TRAIT anxiety how subject felt in the last week

Spielberger’s Anxiety Inventory

Spielberger’s Anxiety Inventory

CSMRAT

50

40

30

20

10

0

mea

n A

NX

IET

Y s

core

postpreSTATE

• Paired Wilcoxon: no significant change within groups

p> 0.05

Spielberger’s Anxiety Inventory

• Paired Wilcoxon: significant decrease in SMR group

CSMRAT

50

40

30

20

10

0

mea

n A

NX

IET

Y s

core post

preTRAIT *

p=0.017

10 %

RESULTSRESULTS

NFB / surgical performanceassociations

AT training vs performance

• Successful within-session AT training correlated significantly with overall technique (R= 0.638, p=0.047)

• Between-session AT training marginally correlated with overall time of performance (R=-0.523, one tailed p=0.060)

• Successful within-session SMR-training ratio was associated with increases in total pause time (R=0.584, p=0.077)

• Pause time was also negatively correlated with task time (R= -0.251)

• A significant partial correlation of within-session learning and pause time was obtained (R=0.703, p=0.035)

SMR training vs performance

X-axis: SMR group split into two equal halves.

GOOD performers were top five subjects with greatest reductions in surgical task time,

BAD performers were bottom half

Y-axis: mean SMR-theta ratio

BARS: between first & second half of all periods between first & second half of all sessions

SMR training vs performance

GOOD performersBAD performers

0.60

0.40

0.20

0.00

SM

R-T

he

ta r

atio

Periods 6 - 9Periods 2 - 5

PERIOD ratio vs performance

• Paired T-test: no significant change within groups

p> 0.05

GOOD performersBAD performers

0.60

0.40

0.20

0.00

SM

R-T

he

ta r

atio

Sessions 5 - 8 Sessions 1 - 4

*

• Paired T-test: significant decrease in BAD performers

p=0.001

SESSION ratio vs performance

10 %

ConclusionConclusion&&

SummarySummary

Summary

SUBJECTIVE MEASURES

•technique improvement in SMR group p=0.04

•trait anxiety reduction in SMR group p=0.02

OBJECTIVE MEASURES

•task time reduction in SMR group p=0.02

•SMR/theta lowered in BAD performers p<0.01

•SMR learning/pause time correlation p=0.03

Model

The results therefore remain in line with previous research on trained enhancement of SMR activity:

• successful reduction of impulsiveness & hyperactivity (Lubar and Shouse 1976)

• enhancement of attention more generally (Sterman 1996; Egner and Gruzelier 2004)

Conclusions

SMR training:

significantly enhances surgical technique

25% less time of instrument contact with eye(can improve post-operation recovery)

AT training:

marginally reduces total surgery time(despite low training efficacies)

AcknowledgementsAcknowledgements

All the surgeons

Prof. John Gruzelier, Merrick Moseley, Philip Bloom and Larry Benjamin

Royal College of Ophthalmology

Dr. Lesley Parkinson