Possible Lingering Effects of Multiple Past Concussions
Table 1
Performance on ImPACT in athletes with 3 or more previous concussions and matched controls.
ImPACT scores
3 or more previous concussions
No previous concussion
t-test
Effect size
Mean
SD
Mean
SD
(P value)
(Cohen’s d)
Raw scores
Verbal memory
86.4
8.1
92.1
10.0
5.14 (.028)
.63
Visual memory
77.1
13.3
82.3
13.1
1.99 (.16)
.39
Processing speed
41.7
7.5
41.3
8.2
0.21 (.88)
.04
Reaction time
0.55
0.08
0.54
0.08
0.56 (.46)
.21
Total symptoms
4.2
7.8
1.6
3.5
1.54 (.13)
.45
Percentile ranks
Verbal memory
44.4
31.8
71.3
27.2
10.75 (.002)
.91
Visual memory
50.5
33.0
63.1
31.1
2.00 (.16)
.39
Processing speed
66.5
29.2
66.8
28.9
0.002 (.97)
.01
Reaction time
54.3
33.1
58.6
29.9
0.24 (.63)
.14
Note: SD: standard deviation. “Percentile ranks” refer to the age adjusted percentile ranks for each raw score from the ImPACT normative data. By convention, Cohen’s effects sizes are interpreted as follows: small: 0.2, medium: 0.5, and large: 0.8.
