Article, Forensic Medicine

Prevalence of strangulation in survivors of sexual assault and domestic violence

a b s t r a c t

Objectives: Both sexual assault (SA) survivors and domestic violence survivors are populations at risk of strangulation injury. Our goal was to identify the prevalence of strangulation in patients who are survivors of SA and DV, identify presence of lethality risk factors in intimate partner violence, and assess differences in strangulation between SA and DV populations.

Methods: We reviewed all patient encounters from our health system’s SA/DV forensic nurse examiner program from 2004 to 2008. Medical records were reviewed for documented physical signs of strangulation or documentation of strangulation. Risk factors for lethality included presence of firearm, threats of suicide/ homicide by the perpetrator, significant bodily injury, loss of consciousness, loss of bladder or bowel con- trol, voice changes, or difficulty swallowing. Data were analyzed with Pearson ?2 and 95% confidence inter- vals (CIs).

Results: A total of 1542 encounters were reviewed. The mean patient age was 30 (range, 13-98) years and 97% were female. Six hundred forty-nine encounters were for DV assaults and 893 were SA. An intimate partner was the assailant 46% of the time; 84% DV vs 16% SA (P b .001). Patients reported strangulation in 23% (351/1542; 95% CI, 21%-25%) of their assaults. The prevalence of strangulation was 38% with DV and 12% with SA (P b .001). Most of the intimate partner encounters with strangulation had significant risk for lethality (97%, 261/269; 95% CI, 94%-99%).

Conclusions: Patients presenting to our forensic nurse examiner program who were survivors of DV were more likely than SA patients to sustain strangulation. Lethality risk factors were common.

(C) 2016

  1. Introduction

It is estimated that 835,000 men and 1.3 million women are phys- ically assaulted by an intimate partner annually in the United States and that 8% of men and 25% of women will be assaulted by their in- timate partner at some point in their lifetime [1]. Almost 20% of

? We received no outside funding.

* Corresponding author at: 525 E Market St, Akron, OH 44304, United States. Tel.: +1 330 375 7530; fax: +1 330 375 7564.

E-mail addresses: [email protected], [email protected]

(C. Mcquown), [email protected] (J. Frey), [email protected] (S. Steer), [email protected] (G.E. Fletcher), [email protected] (B. Kinkopf), [email protected] (M. Fakler), [email protected] (V. Prulhiere).

1 Currently with Aultman Hospital, 2600 Sixth St SW, Canton, OH 44710.

2 Currently with Beth Israel Deaconess Medical Center, 110 Fancis St, Boston, MA 02215.

3 Currently with St Joseph Hospital, 3001 West Martin Luther King Jr Blvd, Tampa FL 33607, and Crisis Center of Tampa Bay, 1 Crisis Center Plaza, Tampa FL 33613.

women and 2% of men have been forcibly raped in their lifetime, and 44% of women and 24% of men experience sexual assault (SA) other than rape during their lifetime [2].

Strangulation is a common method of injury in intimate partner violence assaults [3]. Strangulation is defined by external compression of the blood vessels of the neck causing reduced blood flow to or from the brain [4]. The application of only 4 lb of pressure occludes jugular veins and 5-11 lb occludes Carotid arteries [4].

Resulting signs and symptoms can be from asphyxiation or blunt force injuries to the neck [5]. It is estimated that only 50% of all strangulation survivors present with visible injuries, and some survivors may not remember the strangulation secondary to amnesia caused by Cerebral hypoxia at the time of the assault [5,6]. Lethality risk refers to assessment of a domestic violence (DV) survivors risk of dying from the current situation. This includes the presence of a firearm in the home, threats of suicide/homicide by the abusive partner, significant bodily injury, and sustaining a significant

0735-6757/(C) 2016

strangulation (with loss of consciousness, loss of bladder or bowel control, voice changes, or difficulty swallowing) [5-8]. Although these lethality risks have only been validated specifically in IPV, the majority of all sexual violence survivors know their perpetrator and 45% of rape survivors reported that the perpetrator was an in- timate partner [2].

  1. Materials and methods
    1. Study design

This study was designed as a retrospective observational study. We reviewed all encounters to our health system’s SA and DV eval- uation center from 2004 to 2008. At this facility, adult patients who presented with an SA or DV were evaluated and examined by sexual assault nurse examiners (SANE-A) who also had additional forensic training in the care of DV survivors. In addition, this evalu- ation center’s data included consults from the SANE-A who saw pa- tients admitted to 1 of 2 local hospitals, one a large, tertiary care, level 1 trauma center and the other a hospital with a large substance abuse treatment program and psychiatric Inpatient unit. The second hospital was the actual location of the forensic center. The patient’s decision to work with law enforcement was not a condition for the forensic program to evaluate and treat any patient. The forensic nursing program did require patient consent for patients to be treat- ed; all the services were free of charge to the patient. Rape kits were partially compensated by the state via a small stipend per state pro- tocol. Patients might present to the forensic evaluation center through the emergency department (ED) or might have presented directly to the center after referral from survivors assistance, police, private physician, another ED, or the prosecutor. The program was advertised, and patients could contact the office directly for an eval- uation. When SA or DV patients presented to the ED in the hospital with the forensic center, they were asked if they would like to sign into the ED for a medical screening evaluation or to go directly to the forensic evaluation. Patients were encouraged to be seen in the ED if they had Significant injuries that required pain medication, ob- servation, or diagnostic testing. If they declined a medical screening examination, they were not registered and were taken directly to the forensic center, which kept its own separate medical records. Occasionally, the patient was referred back to the ED after going to

the forensic center if the nurse felt that the patient had injuries needing medical attention. The study was approved by the institu- tional review board that oversaw both hospitals and the SA/DV fo- rensic nursing program.

Participant selection

All patient encounters recorded by the SANE-A from 2004 to 2008 were included in this study. Encounters were removed if upon medical record evaluation study investigators found that nei- ther SA nor DV had occurred. Intimate partner violence was defined as a subset of DV in which the perpetrator was a current/former spouse, boyfriend/girlfriend, dating partner, or ongoing sexual partner. Domestic violence patients in which the perpetrator was a sibling, parent, child, or other family member were excluded from IPV subanalysis.

Data collection and processing

Data were manually collected using a standardized form (Appendix 1). Medical records were manually reviewed by 1 of 2 reviewers for either a history that the patient was strangled or physical signs that strangula- tion had occurred.

Data analysis

Data were entered into a Microsoft Excel file (Microsoft Corporation; Redmond, WA), and analysis was performed with Stata IC (version 11.0; StataCorp LP; College Station, TX). Results are reported using pro- portions with 95% confidence intervals (CIs). Pearson ?2 test was used to compare the presence or absence of an intimate partner to the other variables collected in the study. P value of b.05 was considered statistically significant.

  1. Results
    1. Patient characteristics

A total of 1596 encounters were reviewed; 54 were excluded be- cause they were neither SA nor DV (Fig. 1). The mean patient age was 30 (range, 13-98) years and 97% were female. Most of the women

Non IP male family 35

Non IP male family 25

Non IP female family 18


Acquaintance 755

Non IP 53

IP 590

Not recorded 7

Non IP 780

IP 112

54 no SA or DV

650 DV

892 SA

1596 chart reviewed

SA=sexual assault DV=domestic violence IP= intimate partner

Fig. 1. Relationship of perpetrator.

Table 1

Signs and symptoms of injury

Table 2

Lethality risk, intimate partner strangulation

Percentage of strangulation survivors (n, 95% CI)

Percentage (n = 296, 95% CI)

Injury to neck

57% (198/351, 51%-62%)

Loss of consciousness

25% (67, 20%-31%)

Loss of memory

10% (35/351, 7%-14%)

Difficulty swallowing

31% (82, 25%-36%)

Loss of voice or voice change

40% (139/351, 35%-45%)

Loss of bowel or bladder

9% (23, 6%-13%)

Breathing difficulty

47% (165/351, 42%-53%)

Firearms present

15% (41, 11%-20%)

Involuntary defecation/urination

8% (27/351, 5%-11%)

Threats of suicide, homicide

71% (190, 65%-76%)

Difficulty swallowing

27% (95/351, 23%-32%)

Visible injuries

69% (185, 63%-74%)

Pain with swallowing

31% (107/351, 26%-36%)

Loss of voice

44% (118, 38%-50%)

Persistent Throat pain

31 (107/351, 26%-36%)

were white (69%), 29% were African American, and 2% were other ethnicities. Sixty percent of the subjects were SA patients. There were 892 SA and 650 DV encounters (Fig. 1). The perpetrator of the SA or DV was an intimate partner 46% of the time, more commonly in DV than SA (84% vs 16%, P b .001). More than 5% of assaulted pa- tients were pregnant, 8% of DV and 2% of SA (pregnancy status was not recorded for 4 DV and 55 SA patients).

Main results

Twenty-three percent of patients suffered from strangulation (351/1542; 95% CI, 21%-25%). For 127 (14 DV and 154 SA) patients,

the strangulation status was undocumented. The prevalence of strangulation was 38% with DV and 10% with SA (P b .001). Patients were more likely to be strangled by an intimate partner than other perpetrator (P b .001). Only 20% of total strangulations were done by a non-family member (all SA) (70/351; 95% CI, 16%-26%). Signs of injury and physical complaints were common after strangulation (Table 1). Thirty-six percent of strangulation survivors were stran- gled more than 1 time (125/351; 95% CI, 31%-41%) during the assault. Most of the perpetrators used their hands (93%, 327/351; 95% CI, 90%-96%), and 5% used some other object such as a ligature (16/ 351; 95% CI, 3%-7%). Only about half of the patients were seen in the ED before being seen by the SANE-A (56%, 197/351; 95% CI, 51%-61%). Less than half of the patients were seen by the SANE-A within 12 hours of the injury (43%, 148/351; 95% CI, 37%-48%), and 16% were seen N 72 hours after the assault (58/351; 95% CI, 13%- 21%). Most of the patient encounters with strangulation by an inti- mate partner had significant risk for lethality (97%, 261/269; 95% CI, 94%-99%) in their relationship (Table 2). Data were missing for re- peat strangulation (42/351), firearm (36/351), and perpetrator threats (8/351).

  1. Discussion

Strangulation is a mechanism of violent and potentially fatal assault which deprives the brain of oxygenated blood. It is a form of physical force which can be used to both control and harm the survivor. This study attempted to shed light on the prevalence of strangulation in patients who are either sexually assaulted or sus- tain an assault by their intimate partner. By better understanding the high prevalence of strangulation, practitioners may improve their diligence in screening for this injury and educating their pa- tient on the risks for death and debility which strangulation injury carries.

Strangulation was more likely to occur during IPV than during SA. This is logical because strangulation is a very personal way to hurt someone: during frontal manual strangulation, the assailant is facing the survivor (eye-to-eye) while literally squeezing the very life and breath out of the survivor. In addition, survivors of IPV were more likely to be strangled if the survivor was pregnant or if the perpetrator was

the owner of a firearm. Intimate partner violence was more likely to result in the survivor having visible injury to the neck, difficulty swallowing, dysphagia, or changes in voice, whereas strangulation during SA was less likely to result in these complaints.

Strangulation rates in SA have not been reported widely. It is impor- tant for physicians, police, and prosecutors to know the rates of strangu- lation with both SA and DV. In some jurisdictions, strangulation with the assault results in a higher criminal charge, but proving strangulation when police and medical professionals do not document or search for the signs can be difficult [9-11].

There were several limitations to this study. First, this was a retro-

spective medical record review. As a result, some documentation was found to be incomplete, and not all data points could be completed for each study subject. Another limitation was the fact that medical records were collected by 2 separate examiners–one collected data points from SA, whereas another collected data points from cases involving IPV. It is possible that these 2 examiners had differences in their interpretation of medical records during this study. Many of the subjects had poor recall of the assault secondary to substance-facilitated SA or anoxic injury sec- ondary to strangulation.

Another limitation is the patient’s self-reporting to the forensic center after the assault. Statistics from the largest police depart- ment in our local county showed that there were 2270 DV charges in 2005-2006 (public record reporting available after 2007 did not differentiate DV from other assault or intimidation charges; in 2004, only the Number of calls for violence–not the charges–was reported = 1427) [12]. This suggests that only a small fraction of assaults in the study area sought forensic evaluation/documenta- tion for their assault injuries. One study of nonfatal strangulations in IPV prosecuted by the San Diego City Attorney’s office found that there was a history of prior DV in 89% of the cases [6]. In that study, only 5% of the survivors sought medical attention within 48 hours of the incident [6]. Unfortunately, many fatal strangula- tions may go initially undetected, as the survivor may have no vis- ible signs of injury or may have a history of substance abuse or depression and the death is reported by the assailant [6]. The cause of death is then found during the autopsy which was done to investigate drug overdose, by which time evidence collection of the scene and an undisturbed body are no longer possible, mak- ing prosecution difficult [5]. Having a high suspicion for strangula- tion in unresponsive patients and taking all IPV visits seriously may help with detection of strangulation and counseling of patients to prevent future injury and death.

  1. Conclusions

The study found that strangulation was more likely to be seen in DV assaults than SA in our forensic nurse examiner program. Most strangu- lation survivors had significant lethality risk. delay in seeking care was common, and many patients only visited the DV/SA center rather than the ED.

Appendix 1. Strangulation Study Data Sheet


  1. National Institute of Justice. How widespread is intimate partner violence? Natl Inst Justice; 2007. tent.aspx. Accessed August 8, 2015.
  2. Breiding MJ, Smith SG, Basile KC, Walters ML, Chen J, Merrick MT. Prevalence and characteristics of sexual violence, stalking, and intimate partner violence victimization–national intimate partner and sexual violence survey, United States, 2011. Morb mortal Wkly rep Surveill Summ wash DC 2002, 63(8). ; 2014. p. 1-18.
  3. Wilbur L, Higley M, Hatfield J, et al. survey results of women who have been stran- gled while in an abusive relationship. J Emerg Med 2001;21(3):297-302. http://dx.
  4. Sorenson SB, Joshi M, Sivitz E. A systematic review of the epidemiology of nonfatal strangulation, a human rights and health concern. Am J Public Health 2014; 104(11):e54-61.
  5. Hawley DA, McClane GE, Strack GB. A review of 300 attempted strangulation cases. Part III: injuries in fatal cases. J Emerg Med 2001;21(3):317-22.
  6. Strack GB, McClane GE, Hawley D. A review of 300 attempted strangulation cases. Part I: criminal legal issues. J Emerg Med 2001;21(3):303-9.
  7. Campbell JC, Webster D, Koziol-McLain J, et al. Risk factors for femicide in abusive relationships: results from a multisite case control study. Am J Public Health 2003; 93(7):1089-97.
  8. Glass N, Laughon K, Campbell J, et al. Non-fatal strangulation is an important risk fac- tor for homicide of women. J Emerg Med 2008;35(3):329-35. 1016/j.jemermed.2007.02.065.
  9. Followill P. Alabama domestic violence laws. http://www.criminaldefenselawyer. com/resources/criminal-defense/domestic-violence/alabama-domestic-violence- laws-charges-penalti. [Accessed April 15, 2016].
  10. The Florida legislature. play_Statute&URL=0700-0799/0784/Sections/0784.041.html. [Accessed April 15, 2016].
  11. Besonen J. A new crime, but convictions are elusive. 02/17/nyregion/choking-someone-is-now-a-felony-but-convictions-are-elusive. html?_r=0. [Accessed April 15, 2016].
  12. City of Akron. Police department annual reports. site/3b5153af9b8ad4a7/index.html. [Accessed April 15, 2016].