INTERIM REPORT ON
THE OUTCOME OF COGNITIVE ASSESSMENT IN STUDY 7009
Longitudinal
cognition follow-up and serial DNA/RNA/SERUM/PLASMA/URINE with or without CSF
banking in normal subjects aged 60 to 75 years
Sponsor: PRECISIONMED,
INC
132 North
Acacia Avenue
Solana
Beach, California 92075
Report Prepared by: Catherine
Deeprose and Keith Wesnes
Cognitive
Drug Research Ltd,
CDR House,
Gatehampton Road,
Goring-on-Thames,
RG8 0EN, UK
Tel:
+44 1491 878700
Fax:
+44 1491 878701
Report Status: Interim
3
Date:
October 2007
Contents
1............. summary. 3
1.1.......... DATA COLLECTED.. 3
1.2.......... BASELINE CHARACTERISTICS.. 3
1.3.......... TEST-RETEST RELIABILITY. 4
1.3.1....... Test-retest and change analyses. 4
1.4.......... INDIVIDUAL DECLINE / IMPAIRMENT. 5
2............. DISCUSSION.. 6
3............. REFERENCES.. 6
For
the third interim report CDR data are reported for 73 subjects at Visit 1
(baseline mean age 66.6, SD 5.71), for 52 subjects at Visit 2 (first follow-up
mean age 66.8, SD 6.01), and for 8 subjects at Visit 3 (second follow-up mean
age 68.5, SD 5.88). Age data were only available for 72 subjects at Visit 1, as
age was not available for subject 7090068 who had data at baseline only.
The mean baseline performance indicated
that the healthy elderly subjects recruited into the present study had similar performance
levels compared to CDR normative data for the same age range, with performance
within one standard deviation of control data.
Table 1 Baseline Characteristics
|
|
Range 58 to 83
Mean 66.6 (5.71)
|
Range 58 to 83
Mean 67.6 (5.67)
|
|
|
|
|
|
|
|
|
Power of
Attention (msec)
|
73
|
1252
(148.0)
|
1176
|
1197
(127)
|
|
Continuity of
Attention (#)
|
73
|
91.6
(2.90)
|
1177
|
89.7
(4.82)
|
|
Quality of Working Memory (SI)
|
73
|
1.72
(0.229)
|
620
|
1.56
(0.386)
|
|
Quality of Episodic Secondary Memory (SI)
|
73
|
2.43
(0.323)
|
N/A
|
N/A
|
|
Speed of Memory (msec)
|
73
|
4984
(906.3)
|
N/A
|
N/A
|
|
Paired Associates Learning Easy Pairs Accuracy
|
73
|
92.1
(12.41)
|
N/A
|
N/A
|
|
Paired Associates Learning Hard Pairs Accuracy
|
73
|
86.64
(16.18)
|
N/A
|
N/A
|
|
|
|
|
|
|
|
Test-retest reliability was generally good
(>0.5 at Visit 2 and >0.7 at Visit 3) for the five composite scores with
the exception of Continuity of Attention, though this is likely due to a
restricted data range. Greatest test-retest reliability was seen for Power of
Attention, with the Spearman correlation coefficient >0.8 from Visit 1 to
Visit 2 and >0.7 from Visit 2 to Visit 3 indicating high levels of
test-retest reliability.
Table
2 Analysis Summary
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Power of Attention (msec)
|
1245
(146.6)
|
0.824
(P<0.001)
|
1.69
(86.5)
|
1229
(83.3)
|
0.786
(P=0.021)
|
54.9
(72.8)
|
|
Continuity of Attention (#)
|
90.5
(4.14)
|
0.39
(P=0.004)
|
-0.75
(3.31)
|
93.1
(0.99)
|
-0.097
(P=0.819)
|
1.87
(1.13)
|
|
Quality Working Memory (#)
|
1.76
(0.244)
|
0.60
(P<0.001)
|
0.06
(0.192)
|
1.76
(0.200)
|
0.74
(P=0.366)
|
0.07
(0.205)
|
|
Quality of Episodic Secondary Memory (#)
|
2.40
(0.293)
|
0.52
(P<0.001)
|
-0.04
(0.292)
|
2.60
(0.235)
|
0.88
(P=0.004)
|
-0.01
(0.104)
|
|
Speed of Memory (msec)
|
4632
(776.7)
|
0.64
(P<0.001)
|
-266
(778.7)
|
4519
(694.9)
|
0.69
(P=0.058)
|
-47
(547.1)
|
|
Paired Associates Learning Easy Pairs Accuracy
|
99.0
(4.86)
|
0.12
(P=0.415)
|
5.29
(11.44)
|
100
(*)
|
*
|
3.13
(8.84)
|
|
Paired Associates Learning Hard Pairs Accuracy
|
85.1
(9.96)
|
0.054
(P=0.704)
|
-1.44
(25.44)
|
100
(*)
|
*
|
12.5
(18.90)
|
**
Not estimatable – all values identical.
Individual data were
examined for performance 1.5 or more standard deviations poorer than age-matched
normative data.
For Power of
Attention, six subjects showed performance 1.5 standard deviations poorer than
age-matched norms:
- subject 18 at visit 1 (1497 msecs) and visit
2 (1593 millisecs)
- subject 21 at visit 1 (1513 msecs) and visit
2 (1571 msecs)
- subject 25 at visit 1 (1580 msecs) and visit
2 (1584 msecs)
- subject 28 at visit 1 (1540 msecs) and visit
2 (1532 msecs)
- subject 32 at visit 1 (1556 msecs) and visit
2 (1657 msecs)
- subject 33 at visit 1 (1383 msecs) and visit
2 (1375 msecs)
For Continuity of
Attention, one subject showed performance 1.5 standard deviations poorer than
age-matched norms:
- subject 36 at visit 2 (81)
For Quality of
Working Memory, two subjects showed performance 1.5 standard deviations poorer
than age-matched norms:
- subject 4 at visit 2 (0.87)
- subject 83 at visit 2 (0.90)
Comparison to healthy aged matched
controls at the baseline visit show a study population with mean data which is
comparable to CDR normative data i.e. performance was within one standard
deviation of the controls.
Data for the individual subjects showed
that for Power of Attention, approximately 12% of subjects were 1.5 standard
deviations or more poorer than normative control data at both Visit 1 and Visit
2. This was consistent with the concept of mild cognitive impairment (MCI) as
defined by Petersen (2004) although slightly lower than the cited US study of
prevalence rates, which showed 22% of subjects to meet MCI criteria.
In conclusion, the data showed a
population with cognitive performance comparable to existing normative data.
Some of these subjects may be beginning to show decline or mild impairment.
Petersen RC (2004). Mild cognitive
impairment as a diagnostic entity. Journal of Internal Medicine; 256: 183-194.
