Head Injury Due to Intimate Partner Violence: Injury Characteristics,Subacute Symptoms,and Receipt of Care

Abstract

Women survivors of intimate partner violence (IPV) have increased risk of repetitive neurotrauma in their lifetime but have received less research focus compared with populations of athletes, veterans, and emergency department patients. The current study examined the importance of IPV as a contextual mechanism of injury, by comparing women survivors of IPV based on whether they experienced a head injury due to IPV or a head injury not due to IPV. The analyses involved archival data from in-person interviews conducted with women who received a protective order against an intimate partner in Kentucky from 2001 to 2004 (n = 641). Women were excluded if they reported no head injury history (n = 268), resulting in two groups compared based on a retrospective cohort design: 255 women with at least one self-reported IPV-related head injury (M = 33.8 ± 9.0 years old, range: 19–65; 87.5% White) and 118 women with self-reported head injuries due to reasons other than IPV (M = 32.2 ± 9.1 years old, range: 18–62; 89.0% White). Participants were compared on injury characteristics, lifetime physical and sexual IPV severity, subacute symptoms of head injury, and receipt of care for head injury. Compared with women with head injuries unrelated to IPV, women with IPV-related head injuries reported a higher number of lifetime head injuries (Mdn[range]: IPV-related = 3[1–515] vs. non-IPV-related = 1[1–13], p < 0.001, r = 0.51) and a higher number of head injuries involving loss of consciousness (Mdn[range]: IPV-related = 1[1–35] vs. non-IPV-related = 1[1–4], p < 0.001, r = 0.27), but lower rates of hospitalization (IPV-related = 56.1% vs. non-IPV-related = 73.7%, p = 0.001, odds ratio [OR] = 2.20 [95% confidence interval (CI): 1.36, 3.55]) and formal rehabilitation (IPV-related = 3.2% vs. non-IPV-related = 9.4%, p = 0.011, OR = 3.18 [1.24, 8.13]) following head injury. Women with IPV-related head injuries had greater lifetime severity of physical IPV (p < 0.001, d = 0.64 [0.41, 0.86]) and sexual IPV (p < 0.001, d = 0.38 [0.16, 0.60]). Women with IPV-related head injuries endorsed all symptoms at greater rates than women with non-IPV-related head injuries (ps < 0.001), including physical (e.g., headaches: OR = 3.15 [1.81, 5.47]; dizziness: OR = 2.65 [1.68, 4.16]), cognitive (e.g., trouble problem solving: OR = 2.66 [1.53, 4.64]; inattention: OR = 2.39 [1.52, 3.78]), and emotional symptoms (e.g., depression: OR = 7.39 [4.48, 12.20]; anxiety: OR = 4.60 [2.82, 7.51]). The total count of symptoms endorsed was higher for women with IPV-related head injury than women with head injuries unrelated to IPV (p < 0.001, d = 0.71 [0.49, 0.94]). When controlling for lifetime physical and sexual IPV, IPV-related head injury was independently associated with symptom count (β = 0.261, p < 0.001) and accounted for additional variance in symptom count (ΔR² = 0.06, p < 0.001). Among women survivors of IPV, those reporting IPV-related head injuries reported greater subacute symptoms, but a lower likelihood of being hospitalized or receiving rehabilitative care. Women with self-reported IPV-related head injuries represent an underserved population that is often unevaluated following injury and may have many unmet care needs. Future studies should examine persistent symptoms following IPV-related head injuries and interventions that would be most beneficial for this population.

Introduction

Roughly one-third of women have experienced physical and/or sexual intimate partner violence (IPV) in their lifetime,¹ which stands as a substantial public health issue² affecting primarily women^3,4 and directly impacting their physical and mental health.^5

–8 Women survivors of IPV often experience polytrauma, including both orthopedic and traumatic brain injuries (TBIs).⁹ IPV-related TBI reflects an invisible injury^10,11 and an overlooked public health issue,¹² with researchers calling for increased investigation in this area.^13
–15 The limited research focus on IPV-related TBIs among women is especially concerning. Women tend to experience greater symptom burden,¹⁶ longer recovery,¹⁷ and worse outcomes¹⁸ following TBI than men. The estimated prevalence range of TBI in survivors of IPV is 28–100%, with an estimated 31–75% having multiple TBIs.¹⁹ Based on few studies, IPV-related TBIs are associated with neurological changes,^10,20 worse cognitive functioning,^21,22 and greater post-concussion^23

–26 and mental health symptoms (e.g., depression, post-traumatic stress).^21,27

–30 These studies collectively demonstrate the impact of IPV-related TBI across multiple domains of health and functioning.

As researchers begin to place increased focus on IPV-related TBI,³¹ studies have yet to assess whether TBI due to IPV may differ from TBI not due to IPV. The importance of mechanism of injury has been examined in other contexts, such as studies specifically examining outcomes following sport-related concussion among athletes^32,33 and blast-related TBI among veterans.³⁴ Researchers have even conducted empirical studies comparing cognitive and psychological symptoms based on injury mechanism, comparing blast-related TBI with blunt trauma-related TBI in veterans and finding greater depression and stress associated with blast as a TBI mechanism.³⁵ Similarly, the context of IPV surrounding TBI may contribute to different symptom experiences following injury than TBI unrelated to IPV, in that women often experience contextual psychological factors during IPV, including sustained fear³⁶ and coercive control,³⁷ a potentially higher likelihood of repeated injury,¹³ and barriers to accessing care.³⁸ Among samples of women survivors of IPV, repetitive TBIs are common^10,21,39 and may occur in rapid succession (i.e., within days of each other).¹³ The current study assessed the importance of IPV as a contextual mechanism of self-reported head injury among women survivors of IPV in Kentucky, which has the highest lifetime prevalence of physical IPV among women in the United States (i.e., 42.1%).³

This study involved analysis of an archival data set of interviews conducted with women survivors of IPV who received a protective order against an intimate partner from 2001 to 2004. During this interview, women were asked about their lifetime history of head injuries, both due to IPV and not due to IPV. Of note, head injury reflects a broader term than TBI, which is a primary focus of prior literature reviewed; but head injury was the specific type of injury asked about during data collection for this archival data set. Women with self-reported head injuries due to IPV and women with self-reported head injuries not due to IPV were compared on injury characteristics (i.e., loss of consciousness, number of head injuries), lifetime physical and sexual IPV severity, subacute symptoms of head injury, and receipt of care for head injury. Compared with women reporting non-IPV-related head injuries, we hypothesized that women reporting IPV-related head injuries would report: 1) more head injuries and more frequent loss of consciousness due to head injuries; 2) a higher degree of lifetime physical and sexual IPV severity; 3) greater subacute cognitive, physical, and emotional symptom burden (i.e., within 6 months of worst head injury); and 4) less frequent receipt of hospital-based care and rehabilitation services following head injury. We further hypothesized that differences in symptom severity would remain significantly higher among women reporting IPV-related head injuries even when controlling for lifetime physical and sexual IPV severity.

Methods

Participants

Participants were recruited out of court in urban and rural areas once they obtained protective orders against their intimate partners. Women were approached in the courthouse after obtaining a protective order with permission from each court judge. A member of the research team briefly spoke with the women, if they permitted, and told them about the study and gave them a brochure. Research staff also took their name and phone number, if they were willing to provide this information, so that they could be contacted to invite them for an interview.

Individuals were deemed eligible if they met the following criteria: 1) female; 2) 18 years and older, or 17 and emancipated; and 3) they had obtained a protective order against an intimate partner within 6 months of initial study participation. Women (n = 641) were asked questions about head injury history during an in-person interview, of whom 373 (52.6%) reported at least one head injury from any mechanism, and 255 (39.7%) reported at least one head injury from any mechanism due to IPV. The sample was divided based on whether they reported any prior head injury due to IPV, including 255 with one or more head injuries due to IPV (68.4%) and 118 with only head injuries not due to IPV (31.6%). Participant demographics are provided in Table 1. The groups did not differ in age or racial composition, but differed significantly in terms of education, employment status, and geographic area. Women with IPV-related head injuries, on average, had lower levels of education, higher rates of unemployment, slightly lower annual income, and resided more often in rural settings.

Table 1.

Demographic Characteristics

	Full sample (n = 373)	≥ 1 HI due to IPV (n = 255)	HI not due to IPV (n = 118)	t/χ²	P	d/OR (95% CI)
Age, M(SD)	33.3 (9.0)	33.8 (9.0)	32.2 (9.1)	t = 1.67	0.096	0.19 (-0.03, 0.40)
Age bands, n (%)
< 20	12 (3.2%)	8 (3.1%)	4 (3.4%)
20–29	134 (35.9%)	85 (33.3%)	49 (41.5%)
30–39	137 (36.7%)	94 (36.9%)	43 (36.4%)
40–49	72 (19.3%)	56 (22.0%)	16 (13.6%)
50–59	15 (4.0%)	11 (4.3%)	4 (3.4%)
60+	3 (0.8%)	1 (0.4%)	2 (1.7%)
Race/Ethnicity, n (%)				χ² = 0.18	0.673	OR = 1.16 (0.58, 2.30)
White	328 (87.9%)	223 (87.5%)	105 (89.0%)
Black	30 (8.0%)	21 (8.2%)	9 (7.6%)
Hispanic/Latina	4 (1.1%)	3 (1.2%)	1 (0.8%)
Asian	1 (0.3%)	0 (0.0%)	1 (0.8%)
Native American	2 (0.5%)	2 (0.8%)	0 (0.0%)
Puerto Rican	1 (0.3%)	1 (0.4%)	0 (0.0%)
Biracial	7 (1.9%)	5 (2.0%)	2 (1.7%)
Education, n (%)				χ² = 15.06	<0.001	OR = 3.02 (1.70, 5.38)
8th grade or less	23 (6.2%)	19 (7.5%)	4 (3.4%)
Less than high school	80 (21.4%)	67 (26.3%)	13 (11.0%)
GED	45 (12.1%)	33 (12.9%)	12 (10.2%)
High school diploma	75 (20.1%)	51 (20.0%)	24 (20.3%)
Trade/technical school	19 (5.1%)	12 (4.7%)	7 (5.9%)
Some college	101 (27.1%)	54 (21.2%)	47 (39.8%)
College degree	27 (7.2%)	18 (7.1%)	9 (7.6%)
Some graduate school	1 (0.3%)	0 (0.0%)	1 (0.8%)
Graduate school degree	2 (0.5%)	1 (0.4%)	1 (0.8%)
Employment, n (%)				χ² = 12.52	<0.001	OR = 2.21 (1.42, 3.45)
Unemployed	211 (56.6%)	160 (62.7%)	51 (43.2%)
Part-time employment	42 (11.3%)	23 (9.0%)	19 (16.1%)
Full-time employment	120 (32.2%)	72 (28.2%)	48 (40.7%)
Area, n (%)				χ² = 5.69	0.017	OR = 1.72 (1.10, 2.68)
Urban	138 (37.0%)	84 (32.9%)	54 (45.8%)
Rural	235 (63.0%)	171 (67.1%)	64 (54.2%)
Income ($US), Mdn ^a	12.5k	12.5k	17.5k	t = 1.90	0.059	d = 0.21 (-0.01, 0.43)

Five participants were missing on Income, which was the total self-reported annual income from all sources in the past year; the Income range was the same for all groups (<$1000 to >50,000). χ² test for race was based on percentage White versus percentage other racial/ethnic identities; for education it was based on high school degree versus less than a high school degree; and for employment it was based on unemployed versus part-time or full-time employment.

CI, confidence interval; HI, head injury; IVP, intimate partner violence; OR, odds ratio; SD, standard deviation.

Measures

Head injury history and symptoms

Participants were asked questions related to head injury history, the mechanism of head injury, and symptoms related to the most serious head injury that they had experienced. These questions were introduced with the following statement, “Now, I am going to ask you some questions about head injuries. I will ask about injuries that caused severe pain, being knocked out, coma, being hospitalized, or that resulted in memory problems, visual problems, difficult recovery, or rehabilitation.” Interviewers were directed that minor bumps to the head or incidents that did not result in serious pain, actual injury, or loss of consciousness should not be recorded. Individuals responded to, “Have you ever received a head injury from” the following causes: automobile crash, motorcycle crash, all-terrain vehicle crash, other vehicle crash, assault/abuse, gunshot wound, sports injury, fall/being pushed or shoved, near drowning, and other injury. Participants also noted how many times they experienced a head injury from each of these causes, in addition to stating whether an intimate partner caused the injury.

Further, individuals were asked other information related to their head injuries, including the age at which they experienced their most serious head injury and whether they were knocked out, hospitalized, entered a coma, or received formal rehabilitation after their injuries. In terms of subacute symptoms, participants were asked whether they had any problems with the following cognitive, physical, and emotional symptoms within the first 6 months of their most serious head injury: remembering things, concentrating, solving problems, seeing clearly, physical coordination, dizziness, headaches, controlling temper, feeling anxious, and feeling depressed. Each symptom had a yes/no response option.

Physical and sexual IPV severity

Questions on physical and sexual IPV were adapted from the Conflict Tactics Scales^40,41 based on pilot work with the target population.⁴² Participants were asked whether they had experiences of physical or sexual violence; each specific experience is listed in Table 2. Physical and sexual IPV items were assigned weights based on tactic severity as used in prior research.^43

–47 For physical violence, the items and weights (listed in parentheses) were as follows: twist arm/hair (1), push/shove (1), grab (1), slap (1), kick (2), bite (2), punch/hit with something that could hurt (2), slam against the wall (2), beat up (5), burn/scald (5), choke/strangle (5), threaten with knife/gun (6), try to run down with car (6), and use knife/gun (8). For sexual violence, the items and weights (listed in parentheses) were as follows: sexual insistence without force (1); used threats to do sexual things, including intercourse (2); used physical force to do sexual things, including intercourse (3).

Table 2.

Intimate Partner Violence History

Variable (weight in parentheses)	Full sample (n = 373)	≥ 1 HI due to IPV (n = 255)	HI not due to IPV (n = 118)	t/χ²	P	d/OR (95% CI)
Physical violence, M_W (SD)	21.6 (11.2)	23.8 (11.0)	17.0 (10.2)	t = 5.68	<0.001	d = 0.64 (0.41, 0.86)
Twist arm or hair (1), n (%)	227 (61.0%)	173 (67.8%)	54 (46.2%)	χ² = 15.86	<0.001	OR = 2.46 (1.57, 3.85)
Push or shove (1), n (%)	318 (85.5%)	221 (86.7%)	97 (82.9%)	χ² = 0.914	0.339	OR = 1.34 (0.73, 2.45)
Grab (1), n (%)	323 (86.8%)	226 (88.6%)	97 (82.9%)	χ² = 2.30	0.130	OR = 1.61 (0.87, 2.98)
Slap (1), n (%)	204 (55.0%)	159 (62.6%)	45 (38.5%)	χ² = 18.85	<0.001	OR = 2.68 (1.71, 4.20)
Kick (2), n (%)	167 (45.0%)	134 (52.8%)	33 (28.2%)	χ² = 19.51	<0.001	OR = 2.84 (1.77, 4.56)
Bite (2), n (%)	55 (14.8%)	44 (17.3%)	11 (9.4%)	χ² = 3.98	0.046	OR = 2.02 (1.00, 4.07)
Punch or hit with something (2), n (%)	242 (65.1%)	182 (71.4%)	60 (51.3%)	χ² = 14.24	<0.001	OR = 2.37 (1.51, 3.73)
Slam against the wall (2), n (%)	221 (59.4%)	164 (64.3%)	57 (48.7%)	χ² = 8.09	0.004	OR = 1.90 (1.22, 2.96)
Beat up (5), n (%)	265 (71.0%)	203 (79.6%)	62 (52.5%)	χ² = 28.73	<0.001	OR = 3.53 (2.20, 5.66)
Burn or scald on purpose (5), n (%)	35 (9.4%)	30 (11.8%)	5 (4.3%)	χ² = 5.33	0.021	OR = 3.00 (1.13, 7.94)
Choke/Strangle (5), n (%)	246 (66.1%)	181 (71.0%)	65 (55.6%)	χ² = 8.52	0.004	OR = 1.96 (1.24, 3.08)
Threaten with a knife or gun (6), n (%)	220 (59.3%)	160 (63.2%)	60 (50.8%)	χ² = 5.12	0.024	OR = 1.66 (1.07, 2.59)
Try to run down with a car (6), n (%)	85 (22.8%)	72 (28.3%)	13 (11.0%)	χ² = 13.73	<0.001	OR = 3.20 (1.69, 6.05)
Used a knife or fired a gun on (8), n (%)	175 (47.3%)	128 (50.8%)	47 (39.8%)	χ² = 3.88	0.049	OR = 1.56 (1.00, 2.43)
Sexual violence, M_W (SD)	1.8 (2.2)	2.1 (2.4)	1.3 (1.8)	t = 3.73	<0.001	d = 0.38 (0.16, 0.60)
Sexual insistence (1), n (%)	205 (55.1%)	148 (58.3%)	57 (48.3%)	χ² = 3.23	0.072	OR = 1.49 (0.96, 2.32)
Threats to do sexual things including intercourse (2), n (%)	84 (22.6%)	68 (26.9%)	16 (13.6%)	χ² = 8.15	0.004	OR = 2.34 (1.29, 4.25)
Physical force to do sexual things including intercourse (3), n (%)	103 (27.8%)	83 (32.8%)	20 (16.9%)	χ² = 10.09	0.001	OR = 2.39 (1.38, 4.14)

In terms of missing data, six participants were missing on one or more physical violence items and two participants were missing on one or more sexual violence items.

CI, confidence interval; HI, head injury; IPV, intimate partner violence; OR, odds ratio; Mw, weighted mean; SD, standard deviation.

Procedure

A female staff member recruited women survivors of IPV from four court jurisdictions (three rural and one urban). The 2-h interviews were conducted between October 2001 and December 2004. Interviews were conducted in a public setting of the woman's choice (e.g., libraries, hospitals) once informed consent was received. The interview was conducted in a private area, such as a private room reserved by the research team, without other people around to hear responses to interview questions. The study was approved by a local institutional review board.

Statistical analysis

Women survivors of IPV with and without IPV-related head injuries were compared on mechanism of injury, various characteristics of their injury history, history of physical and sexual IPV, and self-reported symptoms within 6 months of their worst head injury. Group comparisons were based on t-tests for normally distributed variables, Mann-Whitney U tests for non-normally distributed variables, and χ² tests for categorical variables, with respective effect sizes reported for each analysis (d, r and odds ratio [OR]). The sum of symptoms (coded 1 if endorsed, 0 if not endorsed) was used as a dependent variable in a hierarchical regression model, which predicted the sum of symptoms with physical IPV severity and sexual IPV severity in Model 1, and entered a dummy coded IPV-related head injury variable in Model 2 (0 = no IPV-related head injury; 1 = at least one prior IPV-related head injury), examining whether each variable served as an independent predictor and whether head injury accounted for variance in symptom count beyond that explained by IPV severity. The alpha level was set at p < 0.05. Per sensitivity analysis, the sample had sufficient power to detect a small-to-medium effect size.⁴⁸ Because these analyses were exploratory in nature, focused on an underexamined population in prior neurotrauma research, there was no adjustment made for multiple comparisons.

Results

The frequencies of mechanisms of injuries for the full sample are reported in Table 3, along with stratifications based on a history of one or more IPV-related head injuries. Among the total sample, the most common mechanism of head injury was assault or abuse (63.0%), followed by falling or being pushed (46.4%). These mechanisms were the most frequent among women with at least one prior head injury due to IPV (i.e., assault/abuse: 86.3%; fall/being pushed: 46.7%), whereas motor vehicle accidents were the most common mechanism of injury (i.e., 49.2%) among women with no prior head injuries due to IPV. Head injuries due to assault or abuse and falling or being pushed were significantly more common among women reporting prior IPV-related head injuries.

Table 3.

Frequencies of Mechanisms of Head Injury

	Full sample (n = 373)	≥1 HI due to IPV (n = 255)	HI not due to IPV (n = 118)	χ²	P	OR (95% CI)
Motor vehicle accident, n (%)	161 (43.2%)	103 (40.4%)	58 (49.2%)	2.52	0.112	1.43 (0.92, 2.21)
Motorcycle accident, n (%)	9 (2.4%)	9 (3.5%)	0 (0%)	–	0.062	–
ATV accident, n (%)	15 (4.0%)	9 (3.5%)	6 (5.1%)	–	0.572	–
Bicycle accident, n (%)	33 (8.8%)	18 (7.1%)	15 (12.7%)	3.20	0.074	1.92 (0.93, 3.95)
Other vehicle accident, n (%)	5 (1.3%)	4 (1.6%)	1 (0.8%)	–	1.00	–
Assault/Abuse, n (%)	235 (63.0%)	220 (86.3%)	15 (12.7%)	187.28	<0.001	43.16 (22.57, 82.56)
Gunshot wound, n (%)	1 (0.3%)	1 (0.4%)	0 (0%)	–	1.00	–
Sport-related, n (%)	30 (8.0%)	20 (7.8%)	10 (8.5%)	0.04	0.835	1.09 (0.49, 2.40)
Fall/Being pushed, n (%)	173 (46.4%)	139 (54.5%)	34 (28.8%)	21.42	<0.001	2.96 (1.85, 4.73)
Near drowning, n (%)	20 (5.4%)	16 (6.3%)	4 (3.4%)	1.32	0.250	1.91 (0.62, 5.84)
Other injury, n (%)	25 (6.7%)	10 (3.9%)	15 (12.7%)	9.97	0.002	3.57 (1.55, 8.20)

Comparisons were in the frequency of each mechanism of injury between participants with at least one HI due to IPV and participants with no HIs due to IPV, which were made using χ² or Fisher's exact test. Cells with a dash in the χ² column indicate that Fisher's exact test was conducted.

ATV, all-terrain vehicle; CI, confidence interval; HI, head injury; IPV, intimate partner violence; OR, odds ratio.

Physical and sexual intimate partner violence

Histories of physical and sexual violence are reported in Table 2, grouped by the full sample and stratifications based on history of one or more IPV-related head injuries. On average, compared with women with head injuries unrelated to IPV, women with one or more head injuries due to IPV were more likely to report a history of many specific physically and sexually violent experiences in their lifetime. Specifically, women with IPV-related head injuries were more likely to report that their intimate partners had physically assaulted them in the following ways: twisting their arms or hair, slapping, kicking, biting, punching or hitting them with something, slamming them against the wall, beating them up, burning or scalding them on purpose, choking, threatening them with a knife or gun, trying to run them down with a car, and using a knife or gun on them. The two groups reported similar likelihoods of being pushed or grabbed by an intimate partner. With regards to sexual violence, women who experienced IPV-related head injuries were more likely than their counterparts to experience threats and physical force to do sexual things, such as intercourse. The overall severity of physical and sexual IPV was significantly higher among women with at least one IPV-related head injury.

Injury characteristics and receipt of care

Injury characteristics and receipt of care following head injury are reported in Table 4 for the full sample with stratifications based on history of one or more IPV-related head injuries. Compared with women with head injuries unrelated to IPV, women with one or more head injuries due to IPV reported being significantly older when they experienced their most severe head injury, having a significantly higher number of lifetime head injuries, and having more lifetime episodes of loss of consciousness due to head injuries, although overall frequency of having experienced loss of consciousness at least once did not differ between groups. The age difference indicated that a larger percentage of women with head injuries unrelated to IPV experienced those head injuries during childhood and adolescence: 19.7% of the most serious head injuries reported by women with IPV-related head injuries occurred before age 18, whereas 51.3% of the most serious head injuries reported by women with non-IPV-related head injuries occurred before age 18.

Table 4.

Injury Characteristics Among Women With Reported Head Injuries

Injury characteristic	Full sample (n = 373)	≥ 1 HI due to IPV (n = 255)	HI not due to IPV (n = 118)	t/U/χ²	P	d/r/OR (95% CI)
Age at most severe HI, M (SD), Mdn, range^a	22.4 (10.0), 22, 1-53	24.2 (9.2), 23, 3-52	18.5 (10.5), 17, 1-53	t = 5.39	<0.001	d = 0.60 (0.38, 0.83)
Number of HIs, M (SD), Mdn, range^b	12.3 (2.5), 2.5, 1-515	14.5 (40.0), 3, 1-515	1.8 (1.8), 1 (1-13)	U = 5599.5	<0.001	r = 0.51
Ever had LOC due to HI, n (%)^c	207 (55.5%)	144 (56.7%)	63 (53.4%)	χ² = 0.36	0.551	OR = 1.14 (0.74, 1.77)
Number of HIs with LOC, M (SD), Mdn, range^c	2.6 (4.5), 1, 1-35	3.2 (5.3), 1, 1-35	1.3 (0.6), 1, 1-4	U = 3145.5	<0.001	r = 0.27
Ever hospitalized, n (%)	230 (61.7%)	143 (56.1%)	87 (73.7%)	χ² = 10.63	0.001	OR = 2.20 (1.36, 3.55)
Number of hospitalizations, M (SD), Mdn, range^d	1.8 (4.1), 1, 1-60	2.2 (5.2), 1, 1-60	1.2 (0.4), 1, 1-3	U = 4861.0	0.001	r = 0.22
Ever had CT/medical evaluation for HI, n (%)^e	180 (80.7%)	117 (81.8%)	63 (78.8%)	χ² = 0.31	0.578	OR = 1.21 (0.61, 2.41)
Ever experience coma, n (%)	9 (2.4%)	4 (1.6%)	5 (4.2%)	χ² = 2.44	0.118	OR = 2.77 (0.73, 10.53)
Coma duration (days), M (SD), Mdn, range	28.1 (45.0), 4, 0-120	9.8 (12.2), 4, 3-28	42.8 (57.8), 2, 0-120	U = 8.0	0.621	r = 0.16
Received rehabilitation, n (%)	19 (5.1%)	8 (3.2%)	11 (9.4%)	χ² = 6.39	0.011	OR = 3.18 (1.24, 8.13)

Two participants were missing on age at most severe injury, with one reporting a head injury due to IPV and one reporting no head injury due to IPV; ^bone participant was missing on total number of head injuries and five participants were missing on number of head injuries due to IPV; ^cone participant who had a head injury due to IPV was missing on reported LOC and number of head injuries with LOC; ^done participant who did not have a head injury due to IPV was missing on number of hospitalizations; ^eseven participants who did not have a head injury due to IPV were missing on whether they had a CT or medical evaluation after head injury.

There was no difference in the frequencies of experiencing comas following head injuries or coma duration. In terms of care received, women with IPV-related head injuries were less likely to be hospitalized following an injury, but among those hospitalized, women with IPV-related head injuries reported a greater number of hospitalizations. There was no difference in the frequencies of receiving a medical evaluation or computed tomography (CT) scan following head injury among those who were hospitalized. Women with IPV-related head injuries were less likely to receive formal treatment for their head injuries, albeit very few in both groups received any formal treatment (i.e., 5.1% in the total sample).

Symptom reporting

The frequencies of symptom endorsement and comparisons in rates of endorsement are provided in Table 5. They are also displayed visually in Figure 1. All cognitive, physical, and emotional symptoms were reported significantly more often among women with one or more head injuries due to IPV, with the largest differences observed for depression, anxiety, headaches, trouble problem solving, dizziness, and trouble concentrating. The total symptom count was significantly higher among women with IPV-related head injuries (M = 5.3, standard deviation [SD] = 3.1) compared with women with head injuries unrelated to IPV (M = 3.2, SD = 3.0), t = 6.34, p < 0.001, d = 0.71 [95% confidence interval (CI): 0.49, 0.94].

FIG. 1.

Subacute symptom endorsement rates: differences between women with IPV-related and non-IPV-related head injuries. For all symptoms, endorsement rates were significantly different across groups. For statistical comparisons, see Table 5. IPV, intimate partner violence.

Table 5.

Subacute Symptoms Among Women With Reported Head Injuries

	Full sample (n = 370)^a	≥ 1 HI due to IPV (n = 255)	HI not due to IPV (n = 115)^a	χ²	P	OR (95% CI)
Cognitive symptoms
Trouble remembering things, n (%)	148 (40.0%)	113 (44.3%)	35 (30.4%)	6.36	0.012	1.82 (1.14, 2.90)
Trouble concentrating, n (%)	183 (49.5%)	143 (56.1%)	40 (34.8%)	14.38	<0.001	2.39 (1.52, 3.78)
Trouble solving problems, n (%)	107 (28.9%)	88 (34.5%)	19 (16.5%)	12.48	<0.001	2.66 (1.53, 4.64)
Physical symptoms
Trouble seeing clearly, n (%)	150 (40.5%)	114 (44.7%)	36 (31.3%)	5.91	0.015	1.77 (1.11, 2.83)
Trouble with physical coordination, n (%)	103 (27.8%)	81 (31.8%)	22 (19.1%)	6.30	0.012	1.97 (1.15, 3.36)
Trouble with dizziness, n (%)	221 (59.7%)	171 (67.1%)	50 (43.5%)	18.32	<0.001	2.65 (1.68, 4.16)
Trouble with headaches, n (%)	306 (82.7%)	225 (88.2%)	81 (70.4%)	17.56	<0.001	3.15 (1.81, 5.47)
Emotional symptoms
Trouble controlling temper, n (%)	103 (27.8%)	83 (32.5%)	20 (17.4%)	9.07	0.003	2.29 (1.32, 3.97)
Trouble with feeling anxious, n (%)	184 (49.7%)	155 (60.8%)	29 (25.2%)	40.11	<0.001	4.60 (2.82, 7.51)
Trouble with feeling depressed, n (%)	211 (57.0%)	182 (71.4%)	29 (25.2%)	68.90	<0.001	7.39 (4.48, 12.20)

Three participants with no head injury due to IPV were missing on all symptoms.

CI, confidence interval; HI, head injury; IPV, intimate partner violence; OR, odds ratio.

In regression analysis, the total symptom count was predicted with physical and sexual violence severity in Model 1. The model was significant, F(2,363) = 15.64, p < 0.001, R² = 0.08, with physical violence severity (β = 0.224, p < 0.001), but not sexual violence severity (β = 0.102, p = 0.065), independently predicting head injury symptom count. Model 2, which included a dummy coded IPV-related head injury variable, was also significant, F(2,362) = 19.92, p < 0.001, R² = 0.14, with a significant change in ΔR² = 0.06, F(1,362) = 26.32, p < 0.001. In Model 2, physical IPV severity (β = 0.159, p = 0.004) and IPV-related head injury (β = 0.261, p < 0.001) were independently significant, whereas sexual IPV severity remained non-significant (β = 0.085, p = 0.114), indicating that having at least one head injury due to IPV was associated with greater symptom severity independent of IPV severity, and accounted for significantly more variance in symptom count.

Discussion

This study examined whether IPV-related head injuries were associated with differences in injury characteristics, subacute symptoms, and receipt of care compared with non-IPV-related head injuries among women who received a protective order against an abusive partner. The findings indicated that, among women with head injuries, those with head injuries due to IPV had a higher number of lifetime head injuries, a higher number of lifetime head injuries involving loss of consciousness, and—among those hospitalized—a higher number of lifetime hospitalizations due to head injury. Within the first 6 months following their most severe head injury, women survivors of IPV retrospectively reported higher rates of cognitive, physical, and emotional symptoms, which were not accounted for by higher lifetime physical and sexual IPV severity in regression analysis. Lastly, IPV-related head injuries were associated with a lower frequency of ever being hospitalized for head injury and a lower frequency of receiving formal rehabilitation for head injury, although rates of treatment were overall very low.

That said, among those hospitalized, there was no significant difference in the frequency of receiving a medical evaluation or CT scan between groups. Therefore, although there were differences in rates of hospitalization and rehabilitation, women with IPV-related head injuries presenting to the hospital for care received rates of care similar to those with head injuries not due to IPV. Altogether, these findings indicate that women experiencing IPV-related head injuries tended to experience more lifetime head injuries involving loss of consciousness with worse subacute symptoms, but a lower likelihood of being hospitalized or receiving rehabilitative care.

These results correspond with prior research finding associations between cognitive, physical, and emotional symptom severity and brain injury severity among women with IPV-related TBIs.^49,50 The current findings differ from these prior contributions in terms of a comparison group with head injuries not due to IPV, finding that IPV is an important contextual factor of injury that may indicate greater lifetime head injury exposure and worse subacute symptoms. The largest effect sizes were observed for emotional symptoms, with IPV-related head injuries associated with much higher rates of depression (71.4% vs. 25.2%) and anxiety (60.8% vs. 25.2%) compared with non-IPV-related head injuries. These findings align with prior studies finding greater depression, anxiety, and trauma-related symptoms associated with IPV-related TBI.^27,49 Prior research has similarly indicated headaches to be the most commonly endorsed symptom following IPV-related TBI,^23
–25 which was also true for the current sample. Further, cognitive symptoms were reported at higher rates among women with IPV-related head injuries, aligning with prior research on objective cognitive functioning finding associations between IPV-related TBI and worse memory and executive functions.^21,22

Differences in demographic characteristics were noted as well. Women with IPV-related head injuries tended to report older age at their most severe head injury, lower educational attainment, higher rates of unemployment, and greater frequency of rural residence. These findings may, in part, explain some of the other results. Prior research has indicated that, at young and middle adulthood, greater age is associated with worse outcomes following mild head injuries.^51,52 As such, greater subacute symptom severity may be, in part, explained by age differences between the groups at the time of their most severe head injuries. That said, women with IPV-related head injuries often had multiple head injuries, and repetitive injury may have made more recent injuries stand out to them as the most severe due to cumulative effects. Lower educational attainment and higher rates of unemployment indicate lower socioeconomic status among women with IPV-related head injuries, which—among athletes—has corresponded with greater cognitive, physical, and emotional symptoms in the absence of injury.⁵³ Rural settings are often associated with economic disadvantage and reduced access to some health care specialties.^54,55 Some barriers to health care among survivors include cost and control by an abuser,⁵⁶ but unemployment and rural residence may also contribute to reduced access to formal treatment following a head injury due to cost, lack of health care, and limited specialty providers.

This study involved limitations. Data were based on self-report without medical records or collateral report to corroborate information provided. Certain information in medical records would be valuable in determining the presence and severity of the injury, such as Glasgow Coma Scale (GCS) score or neuroimaging results (e.g., skull fracture, macroscopic intracranial abnormality). Some details may be difficult to gauge via self-report, such as estimated frequencies of head injuries or loss of consciousness. The study also relied on retrospective symptom reporting, which may be less accurate with greater time since injury. Women were prompted to recall symptoms following their most serious head injury without guidance for what would make a head injury more serious, meaning contextual factors may influence the experience of severity as opposed to the head injury itself. Head injuries involving IPV may involve many co-occurring experiences that could make the injury seem more severe, such as co-occurring physical injury, greater fear of death due to injury, or other traumatic components of the experience. These contextual factors may be less salient for non-IPV-related head injuries, which could have contributed to differences in retrospective symptom reporting. Symptoms were also only recalled following the most severe head injury, meaning they do not reflect persistent symptoms that the participant may still experience. The symptoms did not represent all possible head injury symptoms, as certain symptom domains (e.g., sleep-arousal^57,58) were not measured.

TBI severity could not be gauged because GCS score was not available, and the duration of loss of consciousness and of post-traumatic amnesia were not measured. This information would have allowed determination of injury severity in alignment with published criteria.^59
–61 Some injuries involved self-reported comas of multiple days, which would indicate severe TBIs, although the comas may have been due to separate medical reasons unrelated to head injury. The direction given to participants to recall prior head injuries was not in alignment with current standard definitions of TBI. The question asked about head injuries that “caused severe pain, being knocked out, coma, being hospitalized, or that resulted in memory problems, visual problems, difficult recovery, or rehabilitation.” Some of these conditions are not consistent with established definitions of brain injury, such as severe pain, which could result from injury to the face or scalp without concurrent injury to the brain. Milder head injuries may also have been missed, such as a head injury involving a brief alteration of consciousness, because interviewers were directed that incidents not involving “serious pain, actual injury, or loss of consciousness should not be recorded.” That said, participants recalled far more head injuries in general (M = 12.3, SD = 2.5) than head injuries specifically involving loss of consciousness (M = 2.6, SD = 4.5). Because this study relied on archival data, the question on head injury was used as it was prepared during initial data collection, despite its intrinsic limitations.

The sample was restricted to urban and rural areas within a single region of Kentucky, which may not be representative of other populations of women with IPV-related head injuries. The sample had a greater representation of participants from rural areas (i.e., 63.0%) than the Kentucky population estimates in the 2000 Census, which estimated 44.2% of the population was from rural areas.⁶² The overall sample (n = 641), inclusive of participants without head injuries, had a lower rate of rural residence (i.e., 54.6%), albeit still higher than the estimated state population. That said, the recruitment strategy was not initially developed to recruit a sample with rural/urban representation consistent with state demographics, and women survivors of IPV may not reflect population demographics, considering some research has shown more chronic and severe IPV experiences by women residing in rural settings.⁶³ There was a relationship between rural residence and experiencing a head injury, in general, and an additional relationship between rural residence and experiencing a head injury due to IPV. However, the inferences based on rural residence were based on group comparisons, which would not be affected by an overrepresentation of participants recruited from rural settings. Rather, that overrepresentation would increase the power of the group comparison and capacity to detect rural/urban differences.

There were also limitations pertaining to the statistical model and approach. Whereas lifetime physical and sexual IPV were examined as covariates, adverse childhood experiences were neither controlled for or interpreted as a variable in analyses, and these experiences may relate to cognitive, physical, and emotional symptoms. There was no adjustment made for multiple comparisons, meaning that some of the findings may be due to statistical chance. This decision was made due to the exploratory nature of research on IPV-related head injury, which has been underexamined in published literature. All significant effects were observed in the hypothesized, intuitive direction, with none appearing spurious; however, they merit replication in future confirmatory research.

Head injury due to IPV remains critically understudied.^13
–15 The current research adds to a growing field of studies assessing symptoms following IPV-related head injuries, providing some novel findings. Among women survivors of IPV, not all head injuries are due to IPV, but women with IPV-related head injuries tended to have more head injuries, more episodes of loss of consciousness, and greater cognitive, physical, and emotional symptom severity within 6 months of their worst injury. Despite having more head injuries and greater symptoms, women with IPV-related head injuries were less likely to receive formal rehabilitation. IPV-related head injuries contribute to unaddressed health needs that interprofessional health care teams could address, including physical problems (e.g., headache),^23
–25 reduced cognitive functioning,^21,22 and mental health symptoms.^21,27

–30 Future research is needed to clarify persistent symptoms following IPV-related head injuries and develop interventions to address unmet health needs associated with this unique contextual mechanism of injury.

Transparency, Rigor, and Reproducibility Summary

This study, based on archival data, and the analysis plan were not pre-registered. The sample included 641 adult cisgender women from Kentucky, USA, who were asked about head injury history during an in-person interview. Participants were excluded if they reported no lifetime head injuries (n = 268), with the final sample including 255 women with one or more IPV-related head injuries and 118 women with head injuries not due to IPV. Before analyses, a sensitivity analysis was conducted to estimate power using the existing sample,⁴⁸ which indicated sufficient power (1-β = 0.99) to detect a medium group difference (d = 0.50, w = 0.30) at p < 0.05 using Mann-Whitney U tests, t-tests, and χ² tests, and a small effect (f² = 0.05) based on R² increase using hierarchical linear regression.

Participants completed in-person interviews from 2001 to 2004, with all head injury history and symptom reporting based on self-report. The statistical analyses were conducted in SPSS and the investigator conducting the statistical analyses was aware of all characteristics of the participants. The reliability and validity of symptom reporting following head injury has been well-established using multiple similar instruments in prior research.⁶⁴ Missing data were minimal, specified in the note under each table, with listwise deletion used in some analyses. Effect sizes and confidence intervals have been reported in the abstract and main text for all outcomes reported. IPV-related head injury reflects a new area in neurotrauma research, making this study exploratory in nature; and, as such, corrections were not made for multiple comparisons. At this time, no replication or external validation studies have been performed or planned. Participants did not consent to data sharing and the data from this study will not be shared. The authors agree to provide the full content of the manuscript on request by contacting the corresponding author.

Footnotes

Acknowledgments

The authors acknowledge the contribution of Robert Walker, MSW, LCSW, who assisted with the development of survey questions pertaining to head injury.

Authors' Contributions

Justin E. Karr conceptualized the study, conducted the statistical analyses, and wrote the manuscript. Sharon E. Leong assisted with statistical analyses, wrote portions of the manuscript, and reviewed and edited the manuscript. TK Logan conceptualized the study, led data collection, and reviewed and edited the manuscript.

Funding Information

This work was supported, in part, by a Building Interdisciplinary Research Careers in Women's Health (BIRCWH) grant (#K12-DA035150) from the National Institute on Drug Abuse (NIDA) of the National Institutes of Health (NIH). The data collection was supported by a National Institute on Alcohol Abuse and Alcoholism (NIAAA) grant (#AA12735-01) and the University of Kentucky General Clinical Research Organization funded by the NIH (#M01RR02602).

Author Disclosure Statement

No competing financial interests exist.

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