grupa_11_naczyniowe_Grysiak.pdf

Journal of Clinical Neuroscience (2003) 10(1), 42–47

ª 2002 Published by Elsevier Science Ltd.

DOI:10.1016/S0967-5868(02)00217-5

Clinical study

Prospective study of neuropsychological and psychosocial

outcome following surgical excision of intracerebral

arteriovenous malformations

Geoffrey A. Marshall 1

MSSC, DIP CLIN PSYCH , Benjamin P. Jonker 2

MBBS , Michael K. Morgan 2

MD , FRACS

FRACS ,

MSSC, DIP CLIN PSYCH

MBBS

Alan J. Taylor 3

PHD

1 Department of Neurology, Royal North Shore Hospital, Sydney, Australia, 2 North and West Cerebrovascular Unit, Department of Surgery, University of Sydney,

Sydney, Australia, 3 Department of Psychology, Macquarie University, Sydney, Australia

Summary In this prospective study the neuropsychological and psychosocial function of 64 patients undergoing surgical resection of cerebral

arteriovenous malformations was examined prior to surgery (T1), one month post-surgery (T2) and one year post-surgery (T3). A mild but

widespread cognitive decline was observed pre-operatively. There was a trend toward decreased neuropsychological function at T2. All

neuropsychological tests showed a trend toward improvement at T3 compared with both pre-operative (generally not statistically signiﬁcant)

and early post-operative values (generally signiﬁcant). Patients were assessed for change between testing times. At T2 patients were more

likely to have deteriorated than improved, whereas at T3 the group which had altered from baseline were more likely to have improved than

deteriorated. Deterioration in some verbal/language tasks was more common for left sided AVMs. Outcome did not differ signiﬁcantly for

patients presenting with haemorrhage. Psychosocial function was unchanged at late follow-up for the majority of patients.

c 2002 Published by Elsevier Science Ltd.

Keywords: cerebral arteriovenous malformation, neuropsychology, cognitive, psychosocial

INTRODUCTION

Patients harboring intracranial arteriovenous malformations

(AVMs) present with a diverse range of clinical features which

include haemorrhage, seizures, headaches, focal neurological

deficits, and mental changes. 1–5 These mental changes have

been well documented in a number of case reports, 6–10 but overt

cognitive impairment appears to account for only a small pro-

portion of overall presentations. 4

Decisions regarding treatment of these lesions are necessarily

complex, and involve balancing the risks and benefits of various

treatment options such as surgical excision, embolization, radio-

surgery, and conservative management. Whilst sufficient data is

available concerning mortality and neurological morbidity, 11–13

cognitive and psychosocial outcome have been reported less fre-

quently. 14 ; 15 Knowledge of the likely cognitive and psychosocial

outcome following surgery could assist clinicians in their decision

making.

In this prospective study a large, relatively unselected group of

patients underwent comprehensive neuropsychological and psy-

chosocial evaluation both prior to and following surgery in order

to determine the effects of AVM excision on cognitive function-

ing.

the neurosurgeon (MKM) and were considered for eligibility by

the following criteria:

1. aged between 16 and 75 years.

2. fluent English speakers.

3. no history of previous neurological or psychological disease

unrelated to the AVM.

4. cerebral AVM was confirmed angiographically prior to

surgery.

5. sufficiently alert and attentive to undertake neuropsychological

testing.

6. initial surgery performed electively or urgently, but not as an

emergency.

Forty-six patients were ineligible, with the most common reasons

being insufficient alertness (15 patients), not fluent English

speakers (11 patients), or initial surgery performed as an emer-

gency (8 patients). The clinical characteristics of the 64 eligible

patients are presented in Table 1.

Neuropsychological assessment

Patients were assessed on 3 occasions: prior to surgery (T1),

within 4–6 weeks post-surgery (T2), and at 12 months post-sur-

gery (T3) (range: 9–24 months). Patients generally underwent

surgery within one month of diagnosis.

As a result of clinical and practical considerations not all pa-

tients received all assessments or tests. One patient was unas-

sessable at T2. Final neuropsychological follow-up (T3) was not

performed in 12 patients. Of those twelve, 2 had died, 6 had left

the area, and 4 declined to return for neuropsychological assess-

ment.

Neurocognitive functioning was evaluated using a variety of

tests, outlined in Table 2. To assess the patients general ability

prior to the current presentation the National Adult Reading Test 16

with adjustment for education 17 was included to estimate pre-

morbid cognitive levels and gauge any longstanding disruption to

cognitive functions. Psychosocial assessment was undertaken on

MATERIALS AND METHODS

Patients

Between July 1992 and March 1996 110 patients underwent

radical surgical excision of supratentorial AVMs of the brain by

Received 28 December 2001

Accepted 15 April 2002

Correspondence to: Professor Michael K. Morgan, MD FRACS, North and

West Cerebrovascular Unit, Department of Surgery, University of Sydney,

Suite 40-41, Level 8, 193 Macquarie Street, Sydney, NSW 2000, Australia.

Tel.: +61-2-9223-6500; Fax: +61-2-9223-6855;

E-mail: morgan@med.usyd.edu.au

Neuropsychological outcome of AVM surgery

Table 1

Clinical characteristics of 64 patients

Statistical analysis

Repeated measures analysis of variance was used to test the sta-

tistical significance of changes in neuropsychological test scores

over time. Since there were 14 tests, an alpha of 0.05/14 ¼ 0.0036

was used for each test, and a sequential Bonferroni test procedure

was used for tests of overall effects. 18 Significant overall results

were followed up by paired comparisons, with alpha set at 0.0036/

3 ¼ 0.0012. The sequential Bonferroni test procedure was used for

each of the three sets of comparisons (T2 vs T1, T3 vs T1 and T3

vs T2).

Since practice effects were likely to play a part, the overall re-

sults were examined in the light of effects reported for some of the

measuresbyotherinvestigators. 19 ; 20 Reliablechangeindices(RCIs)

were also calculated using previously described methods. 21 ; 22

Since it is probable that there were real changes in neuropsy-

chological function for some of the patients who underwent sur-

gery, regardless of the significance of overall changes, RCIs 21 ; 22

were calculated for scores at T2 and T3 vs those at T1. (Since the

size of the effect of practice on differences between T2 and T3

was impossible to gauge, this comparison was not considered. It

seems unlikely that the effect of practice on scores obtained at the

third sitting of a test was as great again as the effect at the second

sitting, especially when T3 came a year after T2.)

The calculation of the RCIs was based on the standard devi-

ation of scores at T1 and the relevant test-retest correlations and

practice effects. 19 ; 20 Ninety percent RCIs were derived.

Analyses of covariance were carried out to see whether

changes in test scores were related to patient characteristics such

as sex, age, hand, and the site, size and grade of the AVM.

The psychosocial measures were grouped into two categories:

intact function and mild or marked decline (there were relatively

few patients in the marked category). Changes in the proportion of

patients in each category over the three test occasions were as-

sessed using Cochrans Q test and significant overall results were

followed up with McNemar tests. Since there were four psycho-

social measures, an alpha of 0.05/4 ¼ 0.0125 was used for overall

tests, and 0.0125/3 was used for the follow-up tests. Analyses

were based on 51 patients who had data for all three times. An-

alyses to see whether changes over time were related to patient

characteristics were carried out with the SAS CATMOD proce-

dure. 23 For this purpose continuous variables such as age were

recoded to make them into categorical variables.

N = 64

N = 51

N = 11

Age

35.6

34.9

Sex

Male

33/64 (52%)

27/51 (53%)

5/11 (45%)

Female

31/64 (48%)

24/51 (47%)

6/11 (55%)

AVM Grade

8/64 (13%)

6/51 (12%)

2/11 (18%)

29/64 (45%)

24/51 (47%)

5/11 (45%)

III

18/64 (28%)

15/51 (29%)

2/11 (18%)

8/64 (13%)

5/51 (9.8%)

2/11 (18%)

1/64 (1.6%)

1/51 (2%)

0/11 (0%)

Side

Left

28/64 (44%)

23/51 (45%)

5/11 (45%)

Right

36/64 (56%)

28/51 (55%)

6/11 (55%)

Size (cm)

0–2

19/64 (30%)

14/51 (27%)

5/11 (45%)

>2–4

27/64 (42%)

23/51 (45%)

3/11 (27%)

18/64 (28%)

14/51 (27%)

3/11 (27%)

Location

23/64 (36%)

20/51 (41%)

3/11 (27%)

Posterior

41/64 (64%)

31/51 (61%)

8/11 (73%)

History

Haemorrhage

32/64 (50%)

21/51 (41%)

3/11 (27%)

Seizures

36/64 (56%)

31/51 (61%)

5/11 (45%)

Preoperative embolization

13/64 (20%)

9/51 (18%)

3/11 (27%)

Associated aneurysms

11/64 (17%)

10/51 (20%)

0/11 (0%)

General neurological

outcome-Modiﬁed Rankin

Scale (MRS)

43/64 (67%)

35/51 (69%)

8/11 (73%)

12/64 (12%)

11/51 (22%)

1/11 (9%)

6/64 (6%)

4/51 (7.8%)

2/11 (18%)

0/64 (0%)

0/51 (0%)

0/11 (0%)

1/64 (1%)

1/51 (2%)

0/11 (0%)

0/64 (0%)

0/51 (0%)

0/11 (0%)

2/64 (2%)

0/51 (0%)

0/11 (0%)

Note: Sixty-four patients were eligible for the study. Of these there were 51

patients who had data for all 3 occasions (T1, T2, T3). Of the remaining 13

patients: 2 died (one of pancreatitis, one of unrelated septicemia 3 months

post-op), 1 was unassessable at early follow-up (T2), and 10 did not attend

late follow-up (T3) because they had left the area (6 patients) or declined to

return for testing (4 patients). Therefore: N ¼ 64 represents the entire study

population; N ¼ 51 represents those patients included in statistical analysis;

N ¼ 11 represents those patients for whom data was incomplete (excluding

the 2 patients which died).

Table 2

Neuropsychological measures

RESULTS

Study population

Demographic data for the 64 eligible patients is provided in Table

1, along with the equivalent information for the 51 patients who

were included in statistical analysis, and the eleven patients ex-

cluded from analysis because of incomplete data (excluding the 2

patients who died). Patients with data on all 3 occasions did not

differ significantly with those who were excluded. As can be seen

in Table 1, the patient sample who underwent statistical analysis

in this study is representative of the study population, and there is

no evidence that patients unavailable for neuropsychological

testing were in any way different from those who were available

to undertake neuropsychological testing.

Function

Neuropsychological test

General cognitive ability

WAIS-R Full Scale IQ 44

WAIS-R Verbal IQ 44

WAIS-R Performance IQ 44

Attention

Digit Span 44

Mental processing speed

Digit Symbol 44

Visual perception

Rey Complex Figure Test 45

Memory and learning

Logical Memory I&II 46

Visual reproduction I&II 46

Rey Auditory Verbal Learning Test (Total) 45

Naming

Boston Naming Test 47

Verbal ﬂuency

Controlled Oral Word Association Test 48

Executive ability

Mazes 49

the basis of interview and measured level of drive, independence,

occupational status, and affective disturbance. Each measure was

rated on a 3 point scale where 1 represented intact function, 2

represented a mild decline, and 3 represented a marked decline in

the area concerned. All assessments were performed by a single

neuropsychologist (GAM).

Premorbid cognitive function

Comparison of estimated IQ with measured FSIQ, VIQ, and PIQ

revealed a small but statistically significant difference, each actual

IQ measurement lower than the estimated IQ (Table 3). Separate

analysis on the basis of AVM grade, site, and size did not show

ª 2002 Published by Elsevier Science Ltd.

Journal of Clinical Neuroscience (2003) 10(1), 42–47

Marshall et al.

Table 3

Estimated and measured general cognitive ability prior to surgery

IQ scores decreased despite a presumed practice effect), none

reached significance. In addition, none of the adjusted differences

between T1 and T3 was significant. The only difference for the

LMI scores which remained significant was that between T1 and

T3 for LMII (t(48) ¼ 4.6, p < 0 : 0005).

(T1)

Mean

Difference from

Est IQ

Signiﬁcance

Est. IQ

100.7

12.4

–

FSIQ

96.1

14.5

) 4.7

p < 0:001

Correlates of change

There was no relationship between age, sex, years of education,

hand, size, and grade of the AVM and the nature of the event

preceding diagnosis (seizure, haemorrhage or other) and the

magnitude and direction of change in neuropsychological score

over time. However the interaction between time and site was

significant for REY_Tscores ð p < 0 : 0036 Þ and almost so for VIQ

scores (p ¼ 0 : 005 Þ . In both cases the decrease in the score at T2

(and the recovery from T2 to T3) was much more marked when

the AVM was on the left side than when it was on the right.

VIQ

95.7

14.5

) 5.1

p < 0:001

PIQ

97.7

15.1

) 3.1

p < 0:05

Est IQ: Estimated IQ, FSIQ: WAIS-R Full Scale IQ, VIQ: WAIS-R Verbal IQ,

PIQ: WAIS-R Performance IQ.

any of these factors to be associated with larger differences be-

tween estimated and measured IQ.

Neuropsychological status prior to surgery (T1), at

early follow-up (T2), and at late follow-up (T3)

Two different patterns over time are evident in Table 4. The IQ,

D.Sp, D.Sy, RCFT, Rey_T, COWAT and MAZE scores all show a

decrease from T1 to T2 and an increase at T3 to a level higher

than that at T1. The WMS-R memory scores (LMII, LMII, VRI

and VRII) and the BNTscore, on the other hand, increase from T1

to T2 and from T2 to T3. In the first group of measures, only the

COWAT showed a significant decrease from T1 to T2 (results of

comparisons are shown in the last three columns of Table 4). The

increase from T2 to T3 was significant for all of the IQ measures

and also for the D.Sp, D.Sy and COWATand Maze scores, while

the difference between T1 and T3 was significant for FSIQ and

PIQ. In the second group of measures, the increase from T1 to T2

was significant for LMI and LMII, as was the difference between

T1 and T3 scores.

Reliable changes

The percentage of patients who showed a reliable change in either

a positive or negative direction for each test is shown in Table 5.

At T2 up to 25% of patients showed a decline in scores. For FSIQ,

VIQ, D.Sy and Rey_T, the number of patients whose scores had

changed for the worse outnumbered those whose scores had in-

creased. At T3, patients were more likely to show an increased

score relative to that at T1. For FSIQ, PIQ D.Sy, LMI, LMII, VRI

and VRII the number whose score increased outnumbered those

whose score decreased. The percentage of patients who showed a

reliable decrease in scores between T1 and T3 was greater than

10% for only the VIQ and D.Sp scores. Very few patients whose

scores had not decreased reliably from T1 to T2 showed a reliable

decrease at T3 (1/37 for PIQ, 1/34 for D.Sp and 2/37 for Rey_T).

However, some patients who had shown a reliable decrease at T2

also showed a reliable decrease at T3. The largest numbers oc-

curred for VIQ (6/9), D.Sp (6/9), D.Sy (4/12), PIQ (3/7) and FSIQ

(2/9). Analyses showed that patients whose scores decreased re-

liably from both T1 to T2 and T1 to T3 did not differ on any of the

demographic or AVM variables listed earlier. There was also no

relationship between reliable change from either T1 to T2 or T1 to

T3 and the same patient characteristics. The nearest approach

ð p ¼ 0 : 016 Þ occurred for the change in the Rey_Tscore from T1

to T3: the four patients who showed a reliable decrease tended to

Practice effects

Non-zero practice effects for WAIS IQ scores 19 and LMI and

LMII scores 20 were included in recalculations of the T2 vs T1 and

T3 vs T1 comparisons for these measures shown in Table 4 (the

rounded practice effect given in the papers was added to the ob-

tained difference and the result was divided by the standard error

for the original analysis). Although the decrease in IQ scores

between T1 and T2 became more marked (in the original analysis,

Table 4

Mean scores on neuropsychological tests prior to surgery (T1), early post-surgery (T2) and at long-term follow-up (T3)

Modality

Test

Comparisons

Mean

2v1

3v1

3v2

General cognitive ability

FSIQ

97.2

15.4

96.5

14.5

101.0

15.2

VIQ

97.0

15.1

96.0

12.4

98.6

13.3

PIQ

98.3

16.2

97.9

18.2

103.6

17.2

Attention

D.Sp

10.0

2.7

9.5

2.8

10.4

2.5

D.Sym

Mental processing speed

9.3

3.1

8.4

3.4

9.8

3.4

Visual perception

RCFT

33.0

4.6

32.1

5.4

33.2

4.0

LMI

Memory and learning

26.4

7.7

29.5

7.8

30.8

6.9

LMII

20.5

9.3

25.0

9.7

27.2

8.8

VRI

32.4

8.4

33.2

6.5

34.2

6.2

VRII

29.5

10.2

31.0

9.1

32.3

8.5

REY T

48.6

9.5

46.7

11.0

49.6

9.8

BNT

Naming

51.5

8.8

51.9

8.9

53.3

9.2

Verbal ﬂuency

COWAT

33.4

15.3

27.7

13.1

34.8

16.4

)

Executive ability

MAZE

25.1

5.4

23.2

5.7

26.0

4.3

Note: +or ) Signiﬁcant difference between times at p < 0:05 (sequential Bonferroni-adjusted for three comparisons per test). + indicates that the mean score was

higher at the later time (e.g., T2 in T2 vs T1); ) indicates that the mean score was lower for the later test.

FSIQ: WAIS-R Full Scale IQ, VIQ: WAIS-R Verbal IQ, PIQ: WAIS-R Performance IQ, D.Sp: Digit Span, D.Sym: Digit Symbol, RCFT: Rey Complex Figure Test,

LMI: Logical Memory (Immediate), LMII: Logical Memory (Delayed), VRI: Visual Reproduction (Immediate), VRII: Visual Reproduction (Delayed), REY T: Rey

Auditory Verbal Learning Test (Total), BNT: Boston Naming Test, COWAT: Controlled Oral Word Association Test, MAZE: Mazes.

Signiﬁcant overall time difference at p < 0:05 (sequential Bonferroni-adjusted for 14 tests).

Journal of Clinical Neuroscience (2003) 10(1), 42–47

ª 2002 Published by Elsevier Science Ltd.

Neuropsychological outcome of AVM surgery

Table 5 The percentage of patients who showed a reliable change in

neuropsychological scores from T1 to T2 and T1 to T3

though the overall differences were of small magnitude, they were

highly significant for two of the three indices. These results

suggest that some degree of cognitive impairment is common in

patients harboring AVMs. This is consistent with other contem-

porary studies in which neuropsychological evaluation has been

undertaken. 14 ; 24–27 The current study confirms a mild but wide-

spread cognitive deterioration prior to surgery.

The effect of cognitive decline on an individual patients level

of independence and occupational status depends on the extent

and nature of the decline as well as the specific situation of the

patient. In this series the widespread cognitive decline which was

witnessed was not associated with a consequent reduction in in-

dependence or occupational status in the majority of patients.

The basis of impaired cognition may lie in the effects of

haemorrhage, compression of surrounding tissue, or chronic ce-

rebral hypoperfusion. 14 ; 26 ; 28 Haemorrhage and tissue compression

cause neurologic dysfunction by well-established mechanisms.

The absence of capillaries and consequent low resistance results in

shunting of blood away from viable brain tissue into the AVM.

This produces both regional arterial hypotension and venous hy-

pertension resulting in chronic cerebral hypoperfusion. 29–35 This

may in turn be associated with altered neuronal structure and

function 36 ; 37 and neurological or neuropsychological deteriora-

tion. 2 ; 38–42

T1!T2 T1!T3

%%%%%%

)

0 +

FSIQ 48 19 75 6 6 77 17

VIQ 48 19 71 10 13 73 15

PIQ 49 14 76 10 8 76 16

D.Sp 50 18 68 14 14 68 18

D.Sy 48 25 71 4 8 75 17

LMI 49 8 82 10 2 92 6

LMII 49 8 80 12 0 82 18

VRI 50 2 96 2 2 88 10

VRII 50 2 96 2 2 88 10

Rey_T 45 13 82 4 9 78 13

FSIQ: WAIS-R Full Scale IQ, VIQ: WAIS-R Verbal IQ, PIQ: WAIS-R

Performance IQ, D.Sp: Digit Span, D.Sym: Digit Symbol, LMI: Logical Memory

(Immediate), LMII: Logical Memory (Delayed), VRI: Visual Reproduction

(Immediate), VRII: Visual Reproduction (Delayed), REY T: Rey Auditory

Verbal Learning Test (Total).

)

Table 6 Percentage of patients with deterioration of psychosocial

condition prior to surgery (T1), in the early post-operative period (T2) and

at long term follow-up (T3)

Measure

T1 (%) T2 (%) T3 (%)

Comparisons

2vs1 3vs1 3vs2

Post-operative cognitive outcome (early)

At early post-operative follow-up there was a trend towards re-

duced scores in most areas of assessment. The exception was in

the area of memory and learning in which scores tended to in-

crease. With the incorporation of adjustment for practice effect the

trend toward reduced scores became more marked, and the sig-

nificant increase in some areas of memory and learning was no

longer seen. The only statistically significant result after inclusion

of the practice effect was a decrease in verbal fluency as measured

by COWAT. These results confirm that in the short term (4–6

weeks post-operative) this group of patients showed a trend to-

wards cognitive decline, although the magnitude was small.

The percentage of patients with a reliable change in neuro-

psychological scores was calculated, and when positive implies

the onset of a neuropsychological deficit or improvement in the

given area. Our results demonstrate that for each given neuro-

psychological variable most patients did not show a significant

change from pre-operative status at one month after surgery.

However for the proportion that did show a change (approxi-

mately 25% for most variables), deterioration was more common

than improvement. Patients can be warned that at 4–6 weeks

following surgery they will not yet have improved maximally, and

they should allow up to a full year for cognitive recovery.

Drive

3.9

17.6

9.8

Affect 51 15.7 27.5 19.6

Occupational status 51 2.0 25.5 13.7 +

Independence 51 2.0 15.7 9.8 +

Note: +or ) Signiﬁcant difference between times at p < 0:05 (sequential

Bonferroni-adjusted for three comparisons per test). + indicates that the

proportion of patients with a psychosocial deﬁcit was higher for the later time

(e.g., T2 in T2 vs T1).

Signiﬁcant overall time difference at p < 0:05 (sequential Bonferroni-

adjusted for 4 tests).

be older than the 34 patients whose scores did not change sig-

nificantly (mean age 53.0 [12.6] and 33.5 [11.1]).

Psychosocial measures

The proportion of patients who were judged to have a deficit on

each of the psychosocial measures at each time is shown in Table

6. The pattern was similar for all measures: there was a rise in the

proportion showing a deficit at T2 which declined at T3, but not to

the pre-operative level. The overall change over time was sig-

nificant for Drive, Occupational status and Independence. Follow-

up tests showed a significant increase from T1 to T2 for all three

measures. Only one variable was related to changes in psycho-

social measures. It was found that the increase in deteroration of

Occupational status from T1 to T2 was much greater for patients

with 11or more years of education than it was for those with up to

10 years of education: the deterioration occurred for only one of

the 26 patients in the lower education group and for 11 of the 25

with in the higher education group. Further investigation showed

that of the 18 patients who were in unskilled or semi-skilled oc-

cupations, 17 showed no deterioration in Occupational status from

T1 to T2. Thirteen of these subjects were in the lower educational

group.

Post-operative cognitive outcome (late)

When patients underwent neuropsychological evaluation at late

follow-up (T3) the trend towards cognitive decline witnessed for

most tests at T2 was no longer apparent. Instead, a trend towards

improved neuropsychological function was seen in all tests,

reaching significance in 5/14. The trend towards improved cog-

nitive function remained after adjustment for practice effect, and

was statistically significant for LMII. When outcome data from T3

was compared with T2 this trend was even more marked, reaching

significance in 8/14 tests.

Potential causes, other than practice effect, of improved neu-

ropsychological function following AVM resection include

evacuation of a hematoma, natural recovery following haemor-

rhage, or improvement in cerebral hemodynamics with normali-

DISCUSSION

Preoperative cognitive and psychosocial status

Preoperatively, our patients showed significant reductions in

general cognitive abilities compared with expected levels. Al-

ª 2002 Published by Elsevier Science Ltd.

Journal of Clinical Neuroscience (2003) 10(1), 42–47

Marshall et al.

sation of cerebral perfusion. This is consistent with other studies

which suggest that neuropsychological impairment is at least

partially reversible with surgery. 7 ; 9 ; 15 ; 43

tients showing a change in cognitive function at 1 year,

improvement is slightly more common than deterioration. As

expected, deterioration in some verbal and language tasks is more

common with surgery for left sided AVMs. There is no increased

cognitive morbidity of surgery for patients with hemorrhagic

presentations. Most patients return to a similar level of psycho-

social functioning post-operatively, but a small group deteriorate

in their potential to undertake employment. Surgery continues to

be a highly effective method of AVM obliteration, and our data

suggests that with the use of careful microsurgical techniques

significant cognitive morbidity is unusual.

Effect of correlates of change

A significant difference was found in performance of an auditory

learning task (Rey T) over time, patients with left sided AVMs

showing a more marked deterioration, particularly at early follow-

up. In addition the Verbal IQ scores showed a similar trend, nearly

reaching significance. Since language is predominantly a function

of the left cerebral hemisphere, the poor performance in these

tests, especially at T2 may represent a local effect from resection.

Whilst the localisation of language is widely recognized, most

neuropsychological tests do not represent a single function

or correspond to a single brain locus, and it is therefore not sur-

prising that other correlations between site and test scores were

not found.

There was no significant effect of any of the above factors on

the likelihood of sustaining a reliable change in neuropsycho-

logical function, although there was a trend towards poorer out-

come at T3 in older patients for at least one function (Rey T).

The potentially at risk groups with larger AVMs, higher

Spetzler–Martin grades, and hemorrhagic presentations did not

fare worse than other patients. It must be noted, however, that the

absolute numbers of high grade AVMs were low, and increased

numbers may be required to obtain the statistical power to detect

such an effect. In addition there were a number of patients who

were excluded from our study for insufficient alertness, or re-

quired emergency surgery because of a deterioration. These pa-

tients were almost exclusively patients with haemorrhage. Thus

the haemorrhage patients in our study population must be con-

sidered to represent the more benign side of the spectrum of

hemorrhagic AVM disease.

REFERENCES

1. Mast H, Mohr JP, Osipov A et al. Steal is an unestablished mechanism for the

clinical presentation of cerebral arteriovenous malformations. Stroke 1995; 26:

1215–1220.

2. Olivecrona H, Riives J. Arteriovenous aneurysms of the brain. Arch Neurol

Psychiatry 1948; 59: 567–603.

3. Paterson JH, McKissock W. A clinical survey of intracranial angiomas with

special reference to their mode of progression and surgical treatment: A report

of 110 cases. Brain 1956; 79: 233–267.

4. Perret G, Nishioka H. Report on the cooperative study of intracranial aneurysms

and subarachnoid haemorrhage. Section VI. Arteriovenous malformations and

fistulae reported to the cooperative study. J Neurosurg 1966; 25: 467–490.

5. Wyburn-Mason R. Arteriovenous aneurysm of mid-brain and retina, facial

naevi and mental changes. Brain 1943; 66: 163–189.

6. Wertz RT, Messert B, Collins M, Rosenbek JC, Kao CC. Right hemisphere

language dominance in a case of left hemisphere arteriovenous malformation. J

Speech Hear Disord 1977; 42: 106–112.

7. v Overbeeke JJ, Bosma NJ, Verdonck AFMM, von Huffelen AC. Higher

cortical disorders: An unusual presentation of an arteriovenous malformation.

Neurosurgery 1987; 21: 839–842.

8. Koffler SP, Roberts EV, Mancall EL. Replacement of dominant temporal lobe

by arteriovenous malformation with minimal neuropsychological impairment:

Report of a case. Neuropsychology 1990; 4: 201–213.

9. Carter PL, Morgan M, Urrea D. Psychological improvement following

arteriovenous malformation excision. J Neurosurg 1975; 42: 452–456.

10. Conley F, Moses JA, Helle TL. Deficits of higher cortical functioning in two

patients with posterior parietal arteriovenous malformations: Use of a

standardized Luria–Nebraska neuropsychological battery for pre- and

postoperative assessment. Neurosurgery 1980; 7: 230–237.

11. Morgan MK, Sekhon LH, Finfer S, Grinnell V. Delayed neurological

deterioration following resection of arteriovenous malformations of the brain. J

Neurosurg 1999; 90: 695–701.

12. Morgan MK, Johnston IH, Hallinan JM, Weber NC. Complications of surgery

for arteriovenous malformations of the brain. J Neurosurg 1993; 78: 176–182.

13. Heros RC, Korosue K, Diebold PM. Surgical excision of cerebral arteriovenous

malformations: Late results. Neurosurgery 1990; 26: 570–578.

14. Stabell KE, Nornes H. Prospective neuropsychological investigation of patients

with supratentorial arteriovenous malformations. Acta Neurochir (Wien) 1994;

131: 32–44.

15. Mahalick DM, Ruff RM, Heary RF, U HS. Preoperative versus postoperative

neuropsychological sequelae of arteriovenous malformations. Neurosurgery

1993; 33: 563–570.

16. Nelson. The National Adult Reading Test: Test Manual. 1982 NFER-Nelson,

Windsor 1982.

17. Willshire D, Kinsella G, Prior M. Estimating the WAIS-R IQ from the National

Adult Reading Test: A cross-validation. J Clin Exper Neuropsych 1991; 13.

18. Holm S. A simple sequentially rejective multiple test procedure. Scand J Stat

1979; 6: 65–70.

19. Hermann B, Seidenberg M, Schoenfeld J, Peterson J, Leveroni C, Wyler A.

Empirical techniques for determining the reliability, magnitude, and pattern of

neuropsychological change after epilepsy surgery. Epilepsia 1996; 37: 942–950.

20. Sawrie S, Chelune G, Naugle R, Luders H. Empirical methods for assessing

meaningful neuropsychological change following epilepsy surgery. J Int

Neuropsych Soc 1996; 2: 556–564.

21. Chelune G, Naugle R, Luders H, Sedlak J, Awad I. Individual change after

epilepsy surgery: Practice effects and base-rate information. Neuropsychology

1993; 7: 41–52.

22. Jacobson N, Truax P. Clinical significance: A statistical approach to defining

meaningful change in psychotherapy research. J Consult Clin Psychol 1991; 59:

12–19.

23. Stanish W, Koch G. The use of CATMOD for repeated measurement analysis

for categorical data. In: Proceedings of the Ninth Annual SAS Users group

International SUGI Conference. SAS Institute, Cary, NC 1984; 761–770.

Post-operative psychosocial outcome

There was a significant increase in the number of patients showing

impairment in psychosocial function in the areas of drive, occu-

pational status, and independence at early follow-up. These sig-

nificant deteriorations had resolved by late follow-up, but not to

pre-operative levels. In some patients psychosocial measures were

improved by surgery, but this was unusual. Our results indicate

that whilst some patients had a permanent deterioration in psy-

chosocial function this was unusual.

One sensitive indicator of the effect of AVM resection on

patients ultimate outcome is their ability to return to work in the

same capacity as they left. Our study shows that the deterioration

in occupational status was more profound for patients in the

higher educational group and those in skilled occupations. This

effect was significant at early follow-up, though it was no longer

so at late follow-up. Data regarding the natural history of occu-

pational status in conservatively treated patients is scant. How-

ever, in one report of AVM patients treated conservatively 6/25

(24%) showed reduction in occupational status at a mean follow-

up of 10.6 years. 27 By contrast, at long term follow-up 13.7% of

our patients had some reduction in ability to undertake the same

level of employment.

CONCLUSIONS

We conclude that AVM surgery has a relatively benign effect on

cognitive and psychosocial functioning in the vast majority of

patients. At one year most patients perform similarly to pre-op-

erative levels on most cognitive tasks. Of the small group of pa-

Journal of Clinical Neuroscience (2003) 10(1), 42–47

ª 2002 Published by Elsevier Science Ltd.

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