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7
Attention
OVERVIEW
Deficits in attention are more commonly found among individuals with
more severe traumatic brain injuries (TBI), and may encompass delayed
reaction time, reduced speed of information processing, or challenges with
concentration, forgetfulness, or doing more than one thing at a time (e.g.,
walking and talking). This chapter presents cognitive rehabilitation therapy
(CRT) interventions aimed to restore attentional capacity, divided by phase
of recovery following moderate-severe TBI (i.e., subacute and chronic).
Controlled studies are described in detail within these sections, divided by
treatment comparator arm, followed by descriptions of the noncontrolled
studies. The committee’s conclusions are presented at the end of the chapter.
The committee reviewed six randomized controlled trials (RCTs), in-
cluding two crossover studies, of treatments intended to improve attention.
All six involved modular treatment directed at one or more attentional
processes. All used decontextualized treatment materials, and all were cat-
egorized as restorative. The trials involved a total of 264 study participants;
treatment group sizes in individual trials ranged from 7 to 43 patients.
Nearly all of the patients suffered moderate-severe injuries 6 weeks to many
months prior to study enrollment. Study participants were generally in their
late 20s to early 30s.
The committee did not identify any nonrandomized, controlled paral-
lel group designs of treatments for attention deficits, however it did review
two pre-post single group studies and one single-subject, multiple baseline
experiment. These studies also employed primarily modular restorative
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126 COGNITIVE REHABILITATION THERAPY FOR TBI
treatments, and all were delivered to patients in the chronic phase with
moderate-severe injuries. The committee did not identify any studies assess-
ing CRT interventions for attention in patients with mild TBI. Table 7-1
presents a summary of all included studies in this review.
MODERATE-SEVERE TBI
Subacute Phase of Recovery
Comparator Group: Non-CRT Content
Gray et al. (1992) compared approximately 17 hours of computer
administered modules stressing various dimensions of attention to about
12 hours of recreational computing that excluded externally paced tasks
or tasks that required rapid processing and responding. This study found
a positive effect of training on psychometric measures of attention, par-
ticularly the type that require numerical manipulation in working memory.
These effects grew in significance in follow-up compared to the immediate
posttreatment measures. This pattern is of some concern, since the median
time postinjury was 20 weeks, a point at which natural recovery may be
ongoing; therefore, imbalance in the acuity of injury between groups might
produce such a result. However, time postinjury was statistically controlled
for, and measures of functions unrelated to attention did not show greater
improvement in the treatment group, lending some specificity to the find-
ings. In this study nearly half of the subjects had nontraumatic injuries,
but the authors report no interaction between diagnosis and treatment
benefit. The credibility of this study is compromised due to its nonreport-
ing of sample sizes for analysis posttreatment, especially at the 6-month
follow-up. Furthermore, standard deviations of the outcomes were not
provided.
Comparator Group: Other CRT Content
Novack et al. (1996) studied participants who were 3 to 6 months
postinjury. This study was conducted in an acute inpatient rehabilitation
population approximately 3 to 6 weeks postinjury, a time when many of
the patients were confused and highly impaired. One group received a
structured program of attention training. The other group received a variety
of other rehabilitation interventions that involved cognitive rehabilitation
components that did not specifically focus on attention. Outcomes were
assessed with respect to several psychometric measures of attention as well
as the Functional Independence Measure (FIM). Both groups improved
significantly from pre- to posttreatment, but to a comparable degree.
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TABLE 7-1 Evidence Table: Attention
TBI
Severity
Study N Level Brief Narrative Comparator Outcome Measures Findings
RCT
Gray et al. 31 Mild, Patients with attentional Y • Psychometric measures: Significant differences
1992 moderate, deficits randomized ▪ Paced Auditory Serial between groups
severe to two groups. The Non-CRT Addition Test (PASAT) on psychometric
treatment group received Content: ▪ Wechsler Adult Intelligence measures of attention
computerized attention Recreational Scale-Revised (WAIS-R) at immediate and six-
training including: computing • Frontal functions: month follow-up.
• Reaction time training ▪ Wisconsin Card Sorting Test
• Rapid number (WCST)
comparison ▪ Finger tapping
• Digit symbol transfer ▪ Word fluency
• Alternating Stroop • Other attentional functions:
program ▪ Letter cancellation
• Divided attention tasks ▪ Picture completion
▪ Time estimation
McMillan 145 Moderate Sessions of supervised Y • Test of Everyday Attention Between-group
et al. 2002 mindfulness practice using • Adult Memory and comparison not
an audiotape obtained No or Non-CRT Information Processing Battery significant for any
from Jon Kabat-Zinn. Content: • PASAT measure.
Participants were asked • Group with • Trail Making Test
to practice daily with this therapist • Self-reported:
tape in the intervening contact and ▪ Sunderland Memory
periods. physical Questionnaire
exercise (PE) ▪ Cognitive Failures
• Group with Questionnaire
no treatment ▪ Hospital Anxiety and
Depression Questionnaire
127
continued
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TABLE 7-1 Continued
128
TBI
Severity
Study N Level Brief Narrative Comparator Outcome Measures Findings
▪ General Health
▪ Rivermead Post-
Concussional Symptoms
Questionnaire
Niemann 26 Moderate- Computerized attention Y • Attention Authors report
et al. 1990 Severe training with visual, ▪ Test d2 attention group
auditory, and divided (i.e., Other CRT ▪ PASAT-R improved significantly
both) training components, Content: ▪ Divided Attention Test more than control on
further subdivided into Memory training ▪ Trail Making Test, Part B the three measures
focused and alternating of equivalent • Memory of attention; memory
attention tasks duration and ▪ Rey Auditory Verbal group improved more
Training accompanied intensity Learning Test-Modified than attention group on
by feedback and strategy (RAVLT-M) one measure.
teaching ▪ Block Span Learning Test
Novack 44 Severe Hierarchical training of Y • Wechsler Memory Scale- Between-group
et al. 1996 attention skills for lowest Revised (WMS-R) comparison not
level of functioning Other CRT • Single reaction time significant for any
involved focused and Content: • Choice reaction time measure.
sustained attention, more Unstructured • Functional Independence
challenging tasks requiring stimulation Measure (FIM)—Activities of
selective attention, program Daily Living
alternating attention, and • FIM—Cognition
divided attention. Each • Neuropsychological tests:
level of the hierarchy ▪ Logical Memory I and II
included multiple tasks. ▪ Sentence Repetition Test
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▪ Judgment of Line
Orientation
▪ Trail Making Test
▪ Wide-Range Achievement
Test-Revised (WRAT-R),
arithmetic subtest
▪ Visual imperception
Ruff et al. 15 Severe Two groups received two Y • Attention Attention measures
1994 treatments (attention ▪ Ruff 2 & 7 Selective at posttreatment did
and memory training) Other CRT Attention test not show significant
delivered via THINKable, Content: Group ▪ WAIS-R Digit Symbol between-group
a computer-based, multi- A received ▪ Continuous Performance comparison.
media program. attention Test
training, then • Memory
memory training. ▪ Rey Auditory Verbal
Group B received Learning Test
memory training, ▪ Corsi Block Learning Test
then attention • Behavioral assessments
training.
129
continued
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TABLE 7-1 Continued
130
TBI
Severity
Study N Level Brief Narrative Comparator Outcome Measures Findings
Sohlberg et 14 Moderate- Compares Attention Y • Neuropsychological attention Training showed
al. 2000 Severe Process Training (APT) tests: improvement on
to education, delivered to No or Non-CRT ▪ Trail Making Test PASAT, Stroop, and
two groups in a crossover Content: ▪ PASAT Trail Making Test.
design. APT aims to Placebo—Brain ▪ Gordon Diagnostic Patients reported a
improve memory, learning, Injury Education ▪ Controlled Oral Word significant difference in
and some aspects of and Supportive Association Task (COWAT) attention and memory
executive control. Listening ▪ Covert Orienting in the treatment group
▪ Continuous Performance versus education.
Task Subjects with greater
▪ Stroop task changes had improved
▪ Sternberg tasks score on PASAT.
• Self-report: Significant more
▪ Attention Questionnaire reports of improvement
▪ Brock Adaptive Functioning to daily life (via
Questionnaire (BAFQ) questionnaires) were
▪ Dysexecutive Questionnaire given by participants
(DEX) after APT.
Pre-Post Single Group
Park et al. 23 Moderate- Examined the use of the N • PASAT Post-testing showed
1999 Severe Attention Process Training • Consonant trigrams (Brown- significant improvement
(APT) to determine if Peterson task) on PASAT and
APT improves cognitive • Beck Depression Inventory Consonant trigrams.
function versus learning (BDI) No significant
specific skills. improvement on BDI.
Results are mediated by
lack of control group.
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Stathopoulou 5 Severe Included a “Captain’s N • Electroencephalogram (EEG) Sustained attention,
and Lubar Log” computer training variables alternating attention,
2004 program for attention • WAIS-R and divided attention
skills with tasks for • PASAT improved in three of
vigilance, inattention, • Self-report measure of severity five subjects. Selective
prudence, impulsivity, (of deficit) for memory and attention improved in
focus, variability, and attention symptoms all subjects. Focused
speed. Participants attention improved in
selected, discriminated, or two of five subjects.
matched visual pictures or Results are mediated by
sounds. lack of control group.
Single Subject, Multiple Baseline Experimental Design
Gansler and 4 Severe Hierarchically organized N • Neuropsychological tests: Posttreatment test
McCaffrey attention training program ▪ WMS-R results proved
1991 based on Posner’s four ▪ Trail Making Test not significant for
component model of ▪ Minute Estimation Test all participants.
attention. ▪ Thurstone Word Fluency Participants reported
Test increase in ADLs.
▪ Grooved Pegboard Test
▪ WAIS-R
• Psychological variables for
depression, anxiety, and anger
• Self-report of ADLs
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132 COGNITIVE REHABILITATION THERAPY FOR TBI
Chronic Phase of Recovery
Studies of chronic, moderate-severe TBI included four RCTs (McMillan
et al. 2002; Niemann et al. 1990; Ruff et al. 1994; Sohlberg et al. 2000)
comparing five treatment arms with patients in the chronic phase. Inter-
ventions in three (Niemann et al. 1990; Ruff et al. 1994; Sohlberg et al.
2000) of these RCTs consisted of some form of attention training exercises,
similar to those employed by Gray et al. (1992) (see above), and most were
delivered via computer. Training ranged from 10 to 24 hours and typically
involved several different attention-demanding tasks that progressed in
difficulty with patient improvement. Some treatments included therapist-
delivered goal setting, feedback, and review of performance, including
one study of Attention Process Training (APT), a manualized treatment
approach that specifies therapist feedback more systematically. The fourth
RCT (McMillan et al. 2002), also the largest trial, used mindfulness train-
ing. Unlike the other attention treatments, mindfulness training did not in-
volve practice with attention-demanding tasks but rather separate sessions
focused on breathing. Therapist-led training in this study was fewer than 4
hours for both mindfulness training and the active comparison condition,
but with home practice assigned.
Comparator Group: No or Non-CRT Content
McMillan et al. (2002) compared the effects of instruction in mindful-
ness training to comparable instruction in physical exercise (non-CRT con-
tent) and a no-treatment control where participants received no therapist
contact but were assessed at the same intervals. Thus, this was the only
study that had a comparator arm of no treatment. Outcomes were assessed
in terms of neuropsychological measures of attention as well as several self-
report measures of mental health status and lapses of attention in everyday
life. The mindfulness intervention outcomes on attention were no different
than those of physical exercise or no intervention.
Sohlberg et al. (2000) compared 24 hours of manualized APT deliv-
ered over 10 weeks to 10 hours of brain injury education—a non-CRT
intervention—delivered over the same time period, in an RCT with out-
comes assessed at the point of crossover and again at trial completion.
Outcome measures included standardized neuropsychological measures of
attention, laboratory measures of information processing intended to assess
the functioning of specific neural networks subserving separable attentional
domains, and coded qualitative interviews regarding real-world changes re-
sulting from treatment. This trial found positive effects of attention training
on the Paced Auditory Serial Addition Test (PASAT), a measure of working
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133
ATTENTION
memory and speeded mental addition, and on the Memory for Location
task, a measure of location working memory. On the Stroop task and the
Trail Making Test, members of the APT group were characterized by “low
vigilance” at baseline. The trial did not find such effects on verbal work-
ing memory, verbal fluency, or on the laboratory tasks designed to isolate
the functions of specific neural networks. Although the patients were not
blinded to the content of their treatment, there were significantly more re-
ports of attention improvements in daily life after the APT treatment than
after brain injury education. Lending some support to the validity of these
reports, reports of everyday attention benefits correlated with improvement
in PASAT scores. This was a small study, with 14 participants, all with
moderate-severe injuries. Two subjects were not included in the structured
interview to assess improvement because they did not recall their par-
ticipation in the treatment. This situation is problematic, as it reduces the
sample size to 12 and raises concerns about generalization to patients with
substantial memory impairment. In addition, there were several statistical
tests, with no adjustment for multiple testing.
Comparator Group: Other CRT Content
Two trials (Neimann et al. 1990; Ruff et al. 1994) studied the impact
of an attention training program, compared to a memory training program,
on measures of attention; thus memory training served as the control
treatment.
Neimann et al. (1990) provided approximately 36 hours of training
on three different aspects of attention, or a comparable amount of training
on internal and external memory strategies. Neuropsychological measures
of attention and memory were assessed. Based on a significant result from
a MANOVA test for the four attention measures, the authors reported
“partial support” for the treatment prediction that attention training would
provide more robust impact on attention measures than the comparison
memory training. However, in post hoc testing, only one of the attention
measures differed significantly between groups. Inspection of the pattern of
improvement suggests that three attention measures improved more in the
group that received attention training, and one improved more in the group
that received memory training.
Ruff et al. (1994) conducted a similar study in which the two treat-
ment groups received both attention training and memory training, but in
counterbalanced order. However, the authors did not conduct statistical
testing at the midpoint of treatment (when a parallel group comparison
would have been possible) because of the small sample size. They report
benefit in both domains at the end of combined treatment, but inspection of
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134 COGNITIVE REHABILITATION THERAPY FOR TBI
the pattern of scores at the midpoint suggests that some attention measures
improved more in one group and some in the other.
Pre-Post Designs
Park et al. (1999) studied the effects of 40 hours of APT training in
23 individuals with chronic, moderate-severe TBI using the PASAT and
Consonant Trigrams tests as outcome measures, along with the Beck De-
pression inventory. Stathopoulou and Lubar (2004) studied five people
with severe brain injury between 1.5 and 23 years postinjury. The patients
received 18 hours of attention training using “Captain’s Log,” a commer-
cial computerized product that administers tasks involving various chal-
lenges to verbal and visual attention and memory. Participants were tested
only once pre and once post, using digit span and digit symbol subtests
of the Wechsler Adult Intelligence Scale (WAIS), the PASAT, a continuous
performance test, a self-report measure of severity of a number of atten-
tion and memory symptoms rated on a five-point scale from “no problem”
to “severe problem,” and electroencephalogram (EEG) spectral measures.
These studies—all of which were conducted at a time when rapid natural
recovery would be unexpected—showed improvement in some of the out-
come measures relevant to treatment. However, none of these studies had
an adequate control for practice on the outcome assessments themselves,
which were assessed twice, so none provides strong support for a treat-
ment effect.
Single-Subject, Multiple Baseline Experiment
Gansler and McCaffrey (1991) conducted four single-subject experi-
ments in which individuals with severe TBI—4 to 27 years postinjury—re-
ceived repeated testing on a set of information processing measures modeled
on Posner’s attention components. The measures were administered weekly,
beginning 4 weeks prior to training, during the 8 weeks of training, and at
1 month after training. Training consisted of 8 weeks of hierarchically or-
ganized modules of attention totaling about 64 hours. Other psychological
measures were also administered weekly and neuropsychological measures
at baseline, after training, and at follow-up; participants also completed a
self-assessment of ADL performance and their satisfaction with it. Improve-
ment on attention measures and psychological measures was negligible
for all participants, though there were larger effects on self-appraisal of
ADL performance. This result could suggest that the treatment imparted
compensatory skills for managing attention deficits that were evident in
real-world ADL tasks but not on controlled attention processing tasks.
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135
ATTENTION
However, the result is also consistent with biasing of self-reported benefit
because of expectation.
CONCLUSIONS: ATTENTION
The committee found limited evidence from one RCT (Sohlberg et al.
2000) to support conclusions about the impact on patient-centered
outcomes (quality of life, functional status) in moderate-severe TBI.
The committee found limited evidence from one RCT (Gray et al.
1992) on long-term impact of treatment (6 months) in the subacute
phase as assessed with psychometric measures, particularly the type
requiring numerical manipulation in working memory.
Considering subacute and chronic studies together, the committee
found limited evidence from two studies (Grey et al. 1992; Sohlberg et
al. 2000), that intensive practice of hierarchical attention-demanding
tasks had a positive impact on psycho-metric measures of attention in
the immediate posttreatment period and/or at follow-up.
The review did not include any RCTs or other study designs on CRT
for attention in mild TBI. Two studies (Gray et al. 1992; Novack et al.
1996) provided limited evidence to conclude that CRT improves attention
in subacute, moderate-severe TBI patients. In studies of moderate-severe
TBI patients in the chronic phase of recovery, a few, relatively small RCTs
with several methodologic limitations provided mixed support for treat-
ment benefit. These trials tested intensive practice of hierarchical attention-
demanding tasks on some psychometric measures of attention, with positive
immediate outcomes. However, none studied the durability of benefits, and
only one study assessed treatment impact with respect to patient-centered
outcomes (i.e., Sohlberg et al. [2000] found a preliminary association of
improved psychometric measures of attention with real-world benefits).
Data from pre-post designs, although consistent with some treatment ben-
efit, provide weak support because of the possible confounding effect of
practice on the outcome measures.
Several of the RCTs with equivocal results (Niemann et al. 1990; Ruff
et al. 1994) used intensive memory training as a control condition. Since
all tasks requiring effort place demands on attention, it is possible that the
overlap in treatment outcomes between treatment groups in such studies
reflects the overlap in mental demands of treatment content, potentially
attenuating or accounting for the lack of finding of differences in attention
outcomes. Of note, the two studies that provided the strongest support for
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136 COGNITIVE REHABILITATION THERAPY FOR TBI
the efficacy of hierarchical attention training employed non-CRT compara-
tor conditions.
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