


































GSJP Volume 16 final


Graduate Student Journal of  Psychology
2015, Vol. 16

Copyright 2015 by the Department of  Counseling and Clinical Psychology
Teachers College, Columbia University

63

An Exploratory Study of  Posttraumatic Stress Disorder, 
Sleep Disturbances, and Executive Functioning in Veterans

Shannon Edwards, M.A. 
The Chicago School of  Professional Psychology 

Laurie Benton, PsyD 
Associate Professor 

The Chicago School of  Professional Psychology 

Anne Germain, PhD 
Assistant Professor 

University of  Pittsburgh 

James Iaccino, PhD
Associate Professor  

The Chicago School of  Professional Psychology 

Introduction: Hypervigilance, hyperarousal, and sleep disturbances are components in the diagnosis and 
treatment of  Posttraumatic Stress Disorder (PTSD) and other trauma-related diagnoses. The current 
study explores the relationships between PTSD, sleep, and executive functioning among military veterans.
Method: The Immediate Post-concussion Assessment and Cognitive Testing Battery (ImPACT) is uti-
lized to examine the cognitive performance of  18 veterans. Dependent measures included composite 
scores of  verbal memory, visual memory, processing speed, and reaction time from the ImPACT comput-
erized test battery, as well as total symptom scores from the Clinician Administered PTSD Scale (CAPS), the 
Pittsburgh Sleep Quality Index, and the Pittsburgh Sleep Quality Index – Addendum for PTSD (PSQI-A).
5HVXOWV�� � 9HWHUDQV� VKRZHG� VLJQLÀFDQW� GHÀFLWV� LQ� YHUEDO� PHPRU\� DQG� VORZHU� UHDFWLRQ� WLPHV� UHODWLYH� WR� QRU-
mative data.  The veterans did not differ from the normative group on visual memory and process-
LQJ� VSHHG� LQGLFHV�� $IWHU� DGMXVWLQJ� IRU� VOHHS� GLVWXUEDQFHV�� UHDFWLRQ� WLPH� UHPDLQHG� VLJQLÀFDQWO\� FRUUHODWHG�
ZLWK� 376'� V\PSWRP� VHYHULW\� LQ� YHWHUDQV�� &RQFOXVLRQV�� ([HFXWLYH� IXQFWLRQLQJ� GHÀFLWV� LQ� YHUEDO� PHPRU\�
and reaction time are detectable in veterans who endorse clinical and subthreshold symptoms of  PTSD. 

Trauma and the Military
 Researchers have estimated that 50-60% of  indi-
viduals will experience a type of  serious trauma (via 
military combat, sexual assault, perceived horror or 
threat, or another major accident) during their life-
time. Additionally, 5-10% of  individuals have been 
estimated to develop symptomology which quali-
ÀHV� WKHP� IRU� D� FOLQLFDO� GLDJQRVLV� RI � 3RVWWUDXPDWLF�
Stress Disorder (PTSD) (Aupperle, Melrose, Stein, 
& Paulus, 2011). Furthermore, Aupperle et al., have 
suggested that neuropsychological approaches to 
research, which address the frontal lobe or exec-
utive function/dysfunction, may offer addition-
al insight regarding cognitive processes that could 
potentially be affected by traumatic events and 
PTSD. To date, much of  the research has focused 

on learning and memory, which may not necessari-
ly have the same impact on PTSD susceptibility, re-
siliency, and development as executive functioning.   
 The prevalence of  traumatic brain injury (TBI), 
its relationship to veterans diagnosed with PTSD, and 
its impact on frontal lobe or executive functioning is 
also a presently debated topic.  Data from a Veteran 
Affairs Polytrauma Rehabilitation Facility involving 
OEF/OIF Veterans receiving care was studied in 
which the VA research group compared combat-re-
lated TBI (74%) to noncombat TBI (71%). Veterans 
with combat-exposed TBIs reported higher sleep dis-
turbances (>50% vs. <30%) and symptoms of  acute 
stress reaction or PTSD (Taber & Hurley, 2010). 
� 7KH� FRQÁLFWV� LQ� $IJKDQLVWDQ� �2SHUDWLRQ� (Q-
during Freedom [OEF]) and Iraq (Operation Iraqi 
Freedom [OIF]) have resulted in the highest rates of  
military troop mobilization and deployment since the Contact: sme1724@ego.thechicagoschool.edu  



64

Vietnam War (Gewirtz, Polusny, DeGarmo, Khaylis, 
& Erbes, 2010). An exceptional amount of  reliance 
is also being placed on National Guard/Reserve 
(NG/R) groups. Service members returning from 
OEF/OIF have been shown to be at greater risk for 
developing or presenting with mental health issues 
�)UXHK��*UXEDXJK��(OKDL��	�%XFNOH\���������6SHFLÀ-
cally, TBI, PTSD, and Major Depressive Disorder are 
distinct post-combat health outcomes (Ozer, Best, 
Lipsey, & Weiss, 2003). Additionally, research revealed 
self-reports from the NG/R troops of  mental health 
issues (depression, relational issues, and PTSD) are 
more than double those of  active duty service mem-
bers (42.4% versus 20.3%). NG/R troops also dou-
ble the amount of  mental health issues regarding 
(PTSD) screenings both post-deployment (12.7%) 
and 6 months thereafter (24.5%) when compared to 
active duty service members (Gewirtz et al, 2010). 
Statistics collected by Gewirtz et al., (2010), regard-
ing active duty troops versus NG/R troops, supports 
ongoing research efforts which hypothesize that 
non-combat exposed veterans face similar traumatic 
and psychological risks to combat-exposed veterans.  

Importance of  Executive Functioning 
 Executive functioning is a set of  mental process-
es that helps connect past experience with present 
action. Individuals use executive functioning to per-
form activities such as planning, organizing, strate-
gizing, paying attention to and remembering details, 
and managing time and space (Aupperle, Melrose, 
Stein, & Paulus, 2011). Individuals with executive 
IXQFWLRQLQJ� GHÀFLWV�PD\� DOVR� KDYH� D�ZHDNQHVV�ZLWK�
their working memory. Working memory is the abil-
ity to actively maintain and manipulate information 
of  one’s mind over a short period of  time. Work-
ing memory is an important component of  execu-
tive functioning, and is typically affected following a 
traumatic event due to the quick task demand that 
is necessary to encode, retrieve, and manipulate var-
ious stimuli while functioning in daily life (Aupper-
le et al., 2011). Samuelson et al (2006) noted that 
decreased performance on measures of  working 
memory have been found in combat- and sexual as-
sault- related PTSD when compared to victims with-
out PTSD and non-trauma controls. Furthermore, 

working memory is needed to transfer information 
to long-term memory. When working memory is 
impaired, the process of  transferring information is 
likely to be impaired as well (Brenner et al., 2010). 
 Verbal memory refers to the memory of  words 
and other abstractions of  language, while visual 
memory describes the relationship between percep-
tual processing and the encoding, storage, and re-
trieval of  the resulting neural representations (Ap-
perle et al., 2011). Reaction time, also referred to as 
‘mental chronometry,’ is the use of  response time in 
perceptual-motor tasks to infer the content, duration, 
and temporal sequencing of  cognitive operations. 
Processing Speed is one of  the measures of  cogni-
WLYH� HIÀFLHQF\� RU� FRJQLWLYH� SURÀFLHQF\�� ,W� LQYROYHV�
WKH�DELOLW\�WR�DXWRPDWLFDOO\�DQG�ÁXHQWO\�SHUIRUP�UHO-
atively over-learned cognitive tasks, especially when 
KLJK�PHQWDO�HIÀFLHQF\�LV�UHTXLUHG��6WUDXVV��6KHUPDQ��
& Spreen, 2006). PTSD effects memory recall and 
accuracy (Lezak, 2008). While PTSD affects various 
areas of  executive functioning, it has been shown 
WR�PRVW� VLJQLÀFDQWO\� DIIHFW�YHUEDO�PHPRU\� �6WUDXVV��
Sherman, & Spreen, 2006). Researchers have indi-
cated that verbal memory impairment is found to be 
the most consistent cognitive impairment related to 
PTSD. Verbal memory has also been shown to be a 
VSHFLÀFDOO\�SURQRXQFHG�GHÀFLW� LQ�FRPSDULVRQ�WR�YL-
sual memory or processing speed in individuals di-
agnosed with PTSD (Johnsen & Asbjornsen, 2008). 
 Short-term memory is another processes in-
volved with working memory. Short-term memory 
is needed for disposal, integration, processing, and 
retrieval aspects of  memory functioning to ensure 
the working memory aspect of  the cognitive process 
is effective (Turner, Salamat, Drummond, & Brown, 
2007). In the general population, the executive func-
tioning component involved with working memory 
elicits a controlled response to stimuli (e.g., impulse 
control). In individuals diagnosed with PTSD, exec-
utive functioning may be compromised. Individuals 
with PTSD may respond to stimuli with hypervigi-
lance, hyperarousal, and impulsivity (Turner et al., 
������� � ,QGLYLGXDOV� ZLWK� 376'�PD\� KDYH� GLIÀFXOW\�
with an inability to consolidate memories due to trau-
ma, which is also linked to increased autonomic arous-
al and inhibition of  the hippocampus (Aupperle et. 

EDWARDS, BENTON, GERMAIN, IACCINO



65

DO����������([HFXWLYH�IXQFWLRQLQJ�GHÀFLWV�DUH�OLNHO\�WR�
affect the daily functioning of  individuals with PTSD, 
and may also play a prominent role in sleep patterns 
and nightmare production (Levin & Nielsen, 2007). 

Neurobiological Aspects of  Nightmares 
 Nightmares are a core re-experiencing feature 
RI � 376'��1LJKWPDUHV� DUH� FOLQLFDOO\� GHÀQHG� DV� ´LQ-
tensely disturbing dreams that awaken the dreamer 
to a fully conscious state and generally occur in the 
latter half  of  the sleep period” (Hasler & Germain, 
2009, p. 2). As many as 90% of  trauma-exposed 
individuals who develop PTSD report disturbing 
dreams that bear varying degrees of  resemblance to 
the actual traumatic event (Oscar et al., 2010). Ad-
ditionally, dream-related disorders such as posttrau-
matic dreams, nightmares, bad dreams, and recurrent 
dreams are the most frequently reported and most 
persistent symptoms exhibited by trauma victims 
(Kobayashi, Boarts, & Delahanty, 2007). According 
to Stickgold (2005), explicit Rapid Eye Movement 
(REM) sleep models of  the neurobiological states 
of  nightmares potentially provide emotional pro-
cessing and integration of  trauma-related memories. 
REM sleep provides a unique neurobiological state 
that allows for the transfer of  hippocampus-medi-
ated episodic traumatic memories and related amyg-
dala-dependent affect into the cortically distributed 
semantic networks of  the brain. The amygdala is hy-
perreactive to traumatic images during the sleep cycle 
in persons with PTSD, which then produces a night-
mare as a response to the threat-related stimuli, thus 
interfering with the transfer of  traumatic memories 
to higher cortical areas (Germain & Zadra, 2009). 
 A meta-analysis of  20 PTSD studies by Ko-
ED\DVKL��������IRXQG�WKDW�GLIÀFXOWLHV�IDOOLQJ�RU�VWD\LQJ�
asleep were reported by 44%-90% of  veterans with 
PTSD, and that 52%-87% reported having recurrent 
nightmares. Additionally, a recent study was complet-
ed in which 304 of  316 veterans reported combat-re-
lated nightmares (Germain & Zadra, 2009). Over half  
of  the veterans in this sample reported realistic com-
bat dreams, 21% reported conceivable war sequences 
they had not actually experienced, and 26% reported 
dreams that mention or relate to the war, but also in-
cluded fantasy and everyday factors. Furthermore, only 

21% of  the dreams reported by veterans in the study 
were precise replications of  their experienced trau-
matic event, while the majority of  dreams contained 
contrived distortions related to the traumatic event. 
 The current study explores the relationships 
between PTSD, sleep, and executive functioning.

Hypotheses
 The presence and severity of  PTSD symptoms 
was assessed by the Clinician Administered PTSD 
Scale (CAPS), and executive functions were assessed 
by different modules of  The Immediate Post-concus-
sion Assessment and Cognitive Testing (ImPACT), 
and results were compared to norms from age and 
sex-similar groups. The hypotheses were (1) that the 
overall participant group, exhibiting varying symp-
tom severity, would  score lower on visual memory, 
verbal memory, reaction time, and processing speed 
domains compared to normative values; (2) veterans 
with PTSD would show greater impairments than 
veterans without PTSD on the ImPACT domains 
when respectively compared to the normative group; 
and 3) the relationship between PTSD severity and 
H[HFXWLYH� G\VIXQFWLRQV�ZRXOG� UHPDLQ� VLJQLÀFDQW� DI-
ter adjusting for the severity of  sleep disturbances. 
 

Method
Participants
 Between January 2011 and January 2012, partic-
ipants were actively recruited though media advertis-
ing in a northwestern metropolitan area. Participants 
were combat-exposed military veterans diagnosed 
with Posttraumatic Stress Disorder (PTSD) (n = 11) 
and without PTSD (n = 7), all of  whom had self-re-
ported nightmares or nocturnal sleep disturbances. 
Fifteen participants were male and three were female 
between the ages of  18 and 50 years old (M = 24 
years, SD = 2.4). The racial/ethnic composition of  
the participants was fairly homogenous with four-
teen participants identifying as Caucasian, three as 
Asian-American, and one as African-American. Par-
ticipants were assessed via a detailed screening process 
as part of  a concurrent sleep study.  Veterans were 
excluded if  they were over 55 years of  age, or if  they 
had been excluded from the initial study due to med-
ical conditions or medication known to affect sleep. 

PTSD, SLEEP DISTURBANCES, AND EXECUTIVE FUNCTIONING



66

Measures
 As a part of  the parent study, participants also 
completed the Clinician-Administered PTSD Scale 
(CAPS; Blake, Weathers, Nagy, Kaloupek, Gusman, 
Charney & Keane, 1995), the Pittsburgh Sleep Quali-
ty Index (PSQI; Buysse, Reynolds, Monk, Berman & 
Kupfer, 1989) and the Pittsburgh Sleep Quality Index 
Addendum (PSQI-A; Germain, Hall, Krakow, Shear, 
& Buysse, 2005). The Clinician-Administered PTSD 
Scale (CAPS) is a structured interview that measures 
severity of  symptomology and diagnosis of  PTSD. 
The CAPS assesses the frequency and intensity of  
seventeen symptoms using standard questions and 
behaviorally anchored rating scales. Questions in-
clude assessing for nightmares associated with PTSD. 
The CAPS is considered to be the gold standard in 
PTSD assessment (Blake et al., 1995). The inter-rater 
reliability of  the CAPS is high, ranging from 0.92 to 
1.00 for “Frequency” and 0.93 to .98 for “Intensity” 
ratings with the global severity correlation equating 
0.89. The CAPS test-retest reliability ranges from .77-
.96 for the three symptom clusters and from .90-.98 
for the 17-item core symptom scale (Blake et.al, 1995).  
 The Pittsburgh Quality Sleep Index (PSQI) was 
employed as a measure of  disturbing nocturnal be-
havior (sleep disturbances). The PSQI has ten ques-
WLRQV�� DQG� LV� D� ÀOO�LQ�WKH� EODQN� TXHVWLRQQDLUH�� 7KH�
PSQI was developed to qualitatively measure sleep 
quality during the previous month. The instrument 
also discriminates between good and poor sleepers. 
7KH�364,�KDV�D�JOREDO�VFRUH�FRUUHODWLRQ�FRHIÀFLHQW�
for test-retest reliability of  (.87). Similarly, The Pitts-
burgh Quality Sleep Index Addendum (PSQI-A) is a 
self-report instrument designed to assess the frequen-
cy of  seven disruptive nocturnal behaviors (DNB) or 
sleep disturbances commonly associated with PTSD.
 Participants completed the Immediate Post-con-
cussion Assessment and Cognitive Testing (Im-
PACT), which is a computerized neuropsycho-
logical test (Iverson, Lovell, & Collins, 2003). 
 The ImPACT measures several executive func-
tioning composite index scores. This study made 
use of  four: Verbal Memory, Visual Memory, Pro-
cessing Speed, and Reaction Time. The compos-
ite scores are made up of  six modules designed to 

test verbal recognition, visual memory, process-
ing speed, impulse control, and working memory. 
� ,QWUDFODVV� FRUUHODWLRQ� FRHIÀFLHQWV� IRU� WKH� ,P-
PACT include processing speed (.85), reaction time 
(.76), visual memory (.70), and verbal memory (.62) 
(Elbin, Schatz, Covassin, 2011). Resch et.al (2013) 
compared two performance groups, with the sec-
ond group also completing a test of  effort. The 
researchers found that composite score intraclass 
FRUUHODWLRQ� FRHIÀFLHQWV� UDQJHG� IURP� ���� WR� ���� IRU�
the 4 scores in Group 1 and .37 to .76 in Group 2.
 For the current study, data was automatically 
scored with the computerized structure within the 
ImPACT, which provided composite scores for each 
category (Verbal Memory, Visual Memory, Processing 
Speed, and Reaction Time). The ImPACT generated 
the particular composite scores for the present study 
by comparing scores from university male participants 
to individuals in the overall normative sample, and 
provided composite scores. The primary populations 
studied for ImPACT research are typically that of  
VSRUWV�UHODWHG�LQMXULHV��ZKLFK�VXSHUÀFLDOO\�DSSHDUHG�WR�
differ from our sample of  combat-exposed injuries.  
However, the ImPACT has been investigated within 
the military population and yielded a .80-.89 test-re-
test reliability score (Cole et al., 2013). Individuals in 
the PTSD group met full diagnostic criteria for symp-
tomology as indicated by the CAPS. The nPTSD 
group, while self-reporting some symptomology, did 
not reach criteria threshold for a clinical diagnosis of  
PTSD. The two veteran groups were separately com-
pared to the normative sample from the ImPACT.

Procedures
 One-sample t-designs were used to analyze the 
composite scores of  each subtest score generated 
from the ImPACT, and were then compared to the 
mean composite score of  the normative sample. The 
chosen comparison was used due to none of  the par-
ticipants in the current study presenting completely 
free of  symptomology and therefore, they were un-
able to be utilized as part of  a control group. Fur-
ther, the normative group from the ImPACT used 
for comparison was comprised of  university males, 
which was the group which most closely matched 
the current study’s participant sample. While not ide-

EDWARDS, BENTON, GERMAIN, IACCINO



67

al, the limitations with power and sample size were 
recognized and results were interpreted with caution. 
 The ImPACT was administered via computer 
by the primary investigator while being supervised 
by a Ph.D. clinician, the primary investigator of  the 
concurrent sleep study. Participants were informed 
WKH� VWXG\� ZDV� LQ� SDUWLDO� IXOÀOOPHQW� RI � D� GRFWRUDO�
dissertation. The participants navigated through six 
modules. The ImPACT took approximately thirty 
WR� IRUW\�ÀYH� PLQXWHV� WR� DGPLQLVWHU��:KHQ� WKH� ,P-
PACT concluded, participants were afforded time 
WR� DVN� TXHVWLRQV�� DV�ZHOO� DV� JLYHQ�GHEULHÀQJ� VKHHWV�

Results

 The ImPACT computer-generated printout pro-
vided descriptive statistics for each composite score 
based on their overall normative group of  university 
students.  Verbal memory composite score (M = 88.2, 
SD = 12.4), Visual Memory composite score (M = 
72.3, SD = 14.9), Processing Speed composite score 
(M = 35.6, SD = 8.3), and Reaction Time compos-
ite score (M = 0.58, SD = .12) averages and stan-
dard deviations were all provided to the investigators.
 H1: The entire sample of  veterans showed 
VWDWLVWLFDOO\� VLJQLÀFDQW� LPSDLUPHQWV� FRPSDUHG�
to the normative data for IMPACT, on the ver-
bal memory composite score (t (17) = -2.737, p = 
.014; M = 81.72). Reaction time composite scores 
among participants were also slower than nor-
mative data, t (17) = 2.837, p = .011; M = .61.
 H2: The verbal memory composite score was 
VLJQLÀFDQWO\� ORZHU� LQ� YHWHUDQV�ZLWK�376'� (t (11) = 
-3.001, p = .013; M = 78.73), but not in veterans 
without PTSD t (6) = -.658, p > .05, M = 86.43. 
Each group was compared to the ImPACT norma-
tive group, respectively. Further, when compared to 
the ImPACT normative group, individuals diagnosed 
ZLWK�376'�KDG�VLJQLÀFDQWO\�VORZHU�UHDFWLRQ�WLPHV� t 
(10) = 2.610, p = .026; M = .62, indicating they re-
sponded less quickly to tasks that were construct-
HG� WR�PHDVXUH� VSHHG� DQG� HIÀFDF\�� � ,Q� FRPSDULVRQ��
veterans without PTSD responded as quickly as the 
normative sample t (6) = 1.224, p > .05; M = .59.
Both visual memory and processing speed had 
QRQ�VLJQLÀFDQW�ÀQGLQJV� LQ�WKH�RYHUDOO�VDPSOH�JURXS�

(t (17) = -.948, p > .05; M = 74.72 and t (17) = 
-.946, p > .05; M = 35.22), when compared to the 
ImPACT normative group. Additionally, the PTSD 
JURXS� KDG� QRQ�VLJQLÀFDQW� ÀQGLQJV� t (10) = -1.070, 
p > .05; M = 73.28 and t (10) = -2.229, p > .05; M 
= 32.36 when compared to the ImPACT norma-
tive group, as did the PTSD group t (6) = -.148, p > 
.05; M = 77.00 and t (6) = .650, p > .05; M = 39.72 
when compared to the ImPACT normative group. 
 H3: Lastly, results indicated that verbal memory 
DQG�UHDFWLRQ�WLPH�ZHUH�VLJQLÀFDQWO\�FRUUHODWHG�ZLWK�WKH�
PSQI-A (r = .033, p = < .05) and (r = .031, p = < .05), re-
spectively, when adjusting for sleep symptom severity. 

Conclusion

 The results of  the current study coincide with ex-
isting research regarding verbal memory impairments 
in individuals diagnosed with PTSD. The term verbal 
memory encompasses both encoding and retrieval 
of  information. Verbal memory is necessary for the 
processing of  traumatic memories when consider-
ing hyperarousal and the inability to quickly encode 
and retrieve responses concerning external stimuli 
(McClincy, Lovell, Pardini, Collins, & Spore, 2006).  
'LIÀFXOW\�ZLWK�HQFRGLQJ�DQG�SURFHVVLQJ�YLVXDO�VWLP-
uli can lead to increased or prolonged hyper-aroused 
states, increased physiological responses (high blood 
pressure), and other psychological symptoms such as 
increased levels of  anxiety (Frueh, et al., 2007). Reac-
tion time appears to be another area of  functioning 
affected in individuals with PTSD symptompology. 
Research has suggested that individuals diagnosed 
with PTSD, or individuals with symptoms related 
to traumatic memories, have slower reaction times, 
which could be a vicarious consequence of  decreased 
executive functioning (Johnsen & Asbjornsen, 2008). 
Decreased reaction time can lead to slowed response 
to external stimuli, reduced agility in response to 
physical responsibilities, and possibly psychomotor 
slowing while addressing cognitive tasks in employ-
ment or academic settings (Aupperle et al., 2011).
 Commonly, traumatic nightmares are among the 
most treatment-resistant symptoms of  PTSD. When 
utilizing sleep as a correlative variable in the equa-
tion, verbal memory and reaction times appeared to 

PTSD, SLEEP DISTURBANCES, AND EXECUTIVE FUNCTIONING



68

be non-affected in individuals with and without a di-
agnosis of  PTSD. It could be suggested that sleep 
disturbances can decrease verbal memory and reac-
tion time; however, one could also infer that by in-
creasing executive functioning (i.e., strengthening 
verbal memory and reaction time via neurocognitive 
therapeutic interventions), sleep disturbances may 
decrease and vice versa. This is particularly concern-
ing within the veteran population as they are more 
likely to underreport psychological symptoms than 
the general population, which could arguably be 
due to the military culture and training (Port, 2001). 
 Within the general population, executive func-
tioning that is involved with working memory elic-
its a controlled response to stimuli. Research has 
suggested that individuals diagnosed with PTSD 
are more likely than the general population to have 
compromised executive functioning (Aupperle et 
al, 2011) (Johnsen & Asbjornsen, 2008). Individu-
DOV�ZLWK� 376'�PD\� DOVR� KDYH� GLIÀFXOW\� FRQVROLGDW-
LQJ� PHPRULHV� GXH� WR� GHÀFLWV� LQ� ZRUNLQJ� PHPRU\��
which is also linked to increased autonomic arous-
al and inhibition of  the hippocampus (Aupperle et. 
DO��� ������� 7KXV�� H[HFXWLYH� IXQFWLRQLQJ� GHÀFLWV� DUH�
more likely to effect the daily functioning of  in-
dividuals with PTSD than the general population, 
and may also play a prominent role in sleep patterns 
and nightmare production (Levin & Nielsen, 2007).

Limitations
 The primary limitation to the study was the 
homogeneity of  the sample, as well as the sample 
VL]H��:KLOH�ZH�ZHUH�DEOH� WR�REWDLQ�VRPH�VLJQLÀFDQW�
results on two composite scores with a small sam-
ple size, a larger sample would have allowed us to 
make further inferences, particularly when exam-
ining the relationship with sleep disturbances. Ob-
WDLQLQJ� VRPH� VLJQLÀFDQFH� LV� HQFRXUDJLQJ� IRU� IXWXUH�
research, when a larger sample may be possible, 
as well as a more gender, ethnically diverse sam-
ple. This could be sought in future studies in order 
to provide a broader understanding of  how sleep 
and executive functioning may affect different so-
ciocultural groups within the veteran population. 

Directions for Future Research
 The study aspired to determine if  there was a re-
lationship between PTSD, sleep, and executive func-
tioning. While there was a power differential and our 
UHVXOWV�ZHUH�LQWHUSUHWHG�ZLWK�FDXWLRQ��WKH�ÀQGLQJV�GR�
suggest a link between some aspects of  executive func-
tioning, which will likely affect individuals with PTSD 
symptoms. Results also suggested verbal memory and 
reaction times are unaffected by sleep disturbances. 
 Future research could include the implementa-
tion of  an intervention, in a test-retest model, for 
veterans who are experiencing the aforementioned 
symptoms. The determination of  executive func-
tioning impairments could be measured via broad as-
sessment and evaluation protocols (Bromberg, 2003; 
Rutherford et al., 2010). Rather than the unaccom-
panied treatment of  the psychological symptomolo-
gy of  PTSD with primarily trauma-based therapeu-
tic interventions, the addition of  a neurocognitive 
WKHUDSHXWLF� LQWHUYHQWLRQ�FRXOG�EH�EHQHÀFLDO� LI � WKHUH�
were present executive dysfunctions to consider. 
 Research has suggested that a multi-modal ap-
SURDFK�PD\�EH�PRUH�HIÀFDFLRXV�LQ�WKH�WUHDWPHQW�RI �
co-occurring PTSD and neurocognitive dysfunction 
(Davidson & Frances, 1999); although, at this time, 
there is not a substantial amount of  literature that pro-
vides empirically based approaches to this ideation. 
While Aupperle and colleagues (2011) validated that 
increased neuropsychological research is needed to 
identify the effects of  treatment on cognitive function 
and to potentially characterize mechanisms of  current 
PTSD treatments, the ability to identify areas of  focal 
GHÀFLWV� LV� D� VWHS� FORVHU� WKDQ� UHVHDUFKHUV� KDYH� EHHQ�
in the recent past. The option of  providing a differ-
ent type of  treatment opportunity to the civilian and 
military populations could potentially increase their 
quality of  life and afford individuals more opportuni-
ties regarding interdisciplinary treatment and options.

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��������7KH�LQWHUQDWLRQDO�FODVVLÀFDWLRQ��RI �VOHHS�
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EDWARDS, BENTON, GERMAIN, IACCINO



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