Multiple mediation path model of pain’s cascading influence on physical disability in individuals with SCI from Colombia,South America

Abstract

BACKGROUND: Research has begun to document the bivariate connections between pain in individuals with spinal cord injury (SCI) and various aspects of health related quality of life (HRQOL), such as fatigue, social functioning, mental health, and physical functioning.

OBJECTIVE: The purpose of this study was to construct and test a theoretical path model illuminating the stage-wise and sequential (cascading) HRQOL pathways through which pain increases physical disability in individuals with SCI in a sample from Colombia, South America. It was hypothesized that increased pain would lead to decreased energy, which would lead to decreased mental health and social functioning, which both would lead to emotional role limitations, which finally would lead to physical role limitations.

METHODS: A cross-sectional study assessed individuals with SCI (n = 40) in Neiva, Colombia. Participants completed a measure indexing various aspects of HRQOL.

RESULTS: The path model overall showed excellent fit indices, and each individual path within the model was statistically significant. Pain exerted significant indirect effects through all possible mediators in the model, ultimately suggesting that energy, mental health, social functioning, and role limitations-emotional were likely pathways through which pain exerted its effects on physical disability in individuals with SCI.

CONCLUSIONS: These findings uncover several potential nodes for clinical intervention which if targeted in the context of rehabilitation or outpatient services, could result in salubrious direct and indirect effects reverberating down the theoretical causal chain and ultimately reducing physical disability in individuals with SCI.

Keywords

Spinal cord injury pain disability health-related quality of life

1 Introduction

Spinal cord injury (SCI) occurs when vertebrae in the spinal column are broken or dislocated, often resulting from a sudden traumatic blow to the spine (National Institute of Neurological Disorders and Stroke, 2008) or from an infection of the spinal nerve cells, a disruption of blood supply to the spinal cord, or congenital medical conditions (Spinal Cord Injury Network, 2009). The most frequent causes of SCI include motor vehicle accidents, violence, falls, and recreational accidents (McDonald & Sadowsky, 2002). SCI often results in difficulties in mobility, functional independence, activities of daily living, participation, socialization, and employment (Craig, Tran, & Middleton, 2008). Depending on the location and severity of the injury, many physical problems occur, resulting in loss of sensation and paralysis of voluntary muscles, leading to reduced mobility, increased dependence in activities of daily living, lowered vocational capacity, as well as respiratory, cardiovascular, urinary, gastrointestinal, and sexual problems (National Institutes of Health, 2008; Sommer, 2001).

In the United States, an estimated 12,000 new cases of SCI occur each year, representing an incidence of 40 cases per million, with approximately 270,000 persons currently living with SCI (Devivo & Chen, 2011; National Spinal Cord Injury Statistical Center [NSCISC], 2011, 2013). The annual societal cost of care for individuals with SCI, excluding indirect costs such as loss of wages, has been estimated at $19 billion (Cao, Chen, & DeVivo, 2011). Despite rehabilitative options, injuries to the spinal cord are mostly permanent and produce lifelong impairments (McDonald & Sadowsky, 2002). An estimate of SCI prevalence in developing global regions such as Colombia, South America, the focus of the current study, cannot be produced due to a lack of epidemiological data and studies in these areas. However, SCI occurs in 1 out of 40 Colombian patients admitted to general hospitals due to trauma (Jiménez & Fepafem, 2009). Studies conducted in Bogota and Medellin, Colombia report that SCI is one of the most frequent reasons for consultation in health care facilities at all levels of complexity as a result of state violence in the country (Romero, Jimenez, & Roman, 1998; Lugo, Gacia, & Montoya, 2002). Unfortunately, there is a lack of research about health related quality of life (HRQOL) in individuals with SCI living in South America (Wyndaele & Wyndaele, 2006).

In all global regions, longstanding pain is one of the most challenging physical problems after SCI (Mariano, 1992). Once established, it is often difficult to treat successfully (Siddall, 2001). It has been estimated that up to 90% of individuals with SCI will experience chronic pain, and for approximately 50% of these individuals, the pain is considered distressing (Craig et al., 2013; Jensen, Chodroff, & Dworkin, 2007). Pain may in fact have a stage-wise and sequential (cascading) effect on other important HRQOL variables in individuals with SCI. Several SCI studies have reported a positive association between pain and fatigue (Fawkes-Kirby et al., 2008), and both pain and fatigue are negatively associated with physical functioning and mood (Fawkes-Kirby et al., 2008; Widerström-Noga, Felipe-Cuervo, & Yezierski, 2001). Previous research has also shown effects of pain and fatigue on psychological functioning (McColl, Arnold, Charlifue, Glass, Savic, & Frankel, 2003; Perry, Nicholas, & Middleton, 2009), and both pain and fatigue are associated with poorer social integration and mental health (Jensen, Hoffman, & Cardenas, 2005).

Research has begun to document the bivariate connections between pain in individuals with SCI and various aspects of HRQOL, such as fatigue, social functioning, mental health, and physical functioning. Yet no study to date has examined the potential cascading effects of pain across these variables in order to link them in a theoretical causal chain; nor have any of these associations been examined in individuals with SCI from Latin America. As a result, the purpose of this study was to construct and test a theoretical path model illuminating the HRQOL pathways through which pain may increase physical disability in a sample of individuals with SCI in Colombia, South America. It was hypothesized that increased pain would lead to decreased energy, which would lead to decreased mental health and social functioning, which both would lead to emotional role limitations, and finally to physical role limitations.

2 Method

2.1 Participants

Forty individuals with SCI were recruited from Neiva, Colombia to participate in the present study. The mean age of participants was 34.75 years (SD = 11.03), 92.5% were male, and the average years of education was 9.9 (SD = 4.63). In addition, 55% had a diagnosis of paraplegia and 45% tetraplegia, with 35% of all SCIs being caused by violent events.

2.2 Measures

2.2.1 Short form-36 (SF-36)

The SF-36 is a self-report questionnaire and is one of the most widely used instruments to assess health related quality of life (HRQOL; Ware & Sherbourne, 1992). The instrument consists of 36 questions that focus on eight different health dimensions: physical functioning, role-physical (limitations in one’s role due to physical problems), bodily pain, general health, vitality, social functioning, mental health, and role-emotional (limitations due to emotional problems). The bodily pain subscale, in particular, is comprised of the following two items: “How much bodily pain have you had during the past 4 weeks?” and “During the past 4 weeks, how much did pain interfere with your normal work (including both work outside the home and housework)?” This subscale therefore measures overall bodily pain-related quality of life, not neuropathic, musculoskeletal, radicular, or other pain that may be SCI-specific. Responses are weighted on a 0–100 scale, with higher scores representing higher HRQOL. The SF-36 has been recognized as one of the most trusted measures of HRQOL in people with SCI (Post & Noreau, 2005). The SF-36 has been translated into many languages, including Spanish, and has well established reliability and validity in SCI populations (Alonso, Prieto, & Anto, 1995).

2.3 Procedure

Participants were recruited from a non-profit organization called Foundation for the Integral Development of People with Disabilities. This foundation is the only resource available for individuals with physical disabilities living in Neiva, Colombia, and serves as a social work organization, advocacy group, counseling service, and social support network. Research staff recruited participants into the study, and medical records were examined for those who requested SCI services. Inclusion criteria required participants to have been diagnosed after the age of 18 with an SCI, have no self-reported history of psychiatric or other neurological complications, no self-reported history of drug/alcohol abuse before the injury, and be at least 6 months post injury.

Participants who met inclusion criteria were called at home and given information about the study. All individuals who were contacted agreed to participate, but two participants were excluded due to self-reported alcohol or drug problems. Individuals who gave their informed consent then were asked socio-demographic information and history of medical or psychological problems prior to administering the HRQOL questionnaire. One of two research assistant psychologists with SCI themselves administered these items to participants, and the protocol lasted approximately 30–45 minutes. In order to manage potential bias of the research assistant psychologists themselves having SCI, a standardized protocol was used, and the administrations were conducted under the supervision of a university professor.

2.4 Data analysis

A correlation matrix was generated showing bivariate relationships between demographic variables and the eight indices of HRQOL in the SF-36. A path model was then created mirroring the theoretical pathways hypothesized. Variables in the model included pain, energy, mental health, social functioning, role limitation-emotional, and role limitation-physical. Direct effects were examined between all variables (directional arrows in the path model), as well as indirect (mediational) effects from pain to all variables further down the cascade. The following criteria were used to assess goodness of fit for the models: ratio of chi-square to degrees of freedom less than 2.0; traditional fit indices, including the comparative fit index (CFI), goodness of fit index (GFI), adjusted goodness of fit index (AGFI), normed fit index (NFI), incremental fit index (IFI), and Tucker-Lewis index (TLI), higher than 0.90 which would indicate adequate fit (Byrne, 1994; Hu & Bentler, 1999); and a root mean square error of approximation (RMSEA) of 0.08 or less (Tabachnick, Fidell, & Osterlind, 2001).

3 Results

3.1 Correlation matrix

In the correlation matrix (Table 1), older age was associated with reduced pain HRQOL (i.e., greater pain).

Table 1
Correlation matrix

Variable 1 2 3 4 5 6 7 8 9 10 11

1. Age

2. Gender –0.037

3. Education 0.093 –0.061

4. Injury Level (para vs. tetra) –0.214 0.067 0.193

5. Pain –0.430^** –0.004 0.102 0.245

6. Energy –0.107 0.086 0.030 0.330^* 0.505^**

7. Mental Health –0.131 0.169 0.069 0.285 0.339^* 0.788^**

8. Social Functioning 0.052 0.126 –0.020 0.100 0.346^* 0.549^ 0.561^

9. Role Limitations – Emotional –0.114 0.076 0.092 0.404^ 0.294 0.554^ 0.567^ 0.600^

10. Role Limitations – Physical –0.222 0.308 –0.019 0.332^* 0.302 0.397^* 0.354^* 0.522^ 0.691^

11. General Health –0.235 0.135 0.299 0.394^* 0.382^* 0.591^ 0.626^ 0.406^ 0.550^ 0.365^*

12. Physical Functioning –0.304 –0.015 0.148 0.748^** 0.225 0.232 0.272 0.077 0.274 0.324^* 0.320^*

Variable	1	2	3	4	5	6	7	8	9	10	11
1. Age
2. Gender	–0.037
3. Education	0.093	–0.061
4. Injury Level (para vs. tetra)	–0.214	0.067	0.193
5. Pain	–0.430^**	–0.004	0.102	0.245
6. Energy	–0.107	0.086	0.030	0.330^*	0.505^**
7. Mental Health	–0.131	0.169	0.069	0.285	0.339^*	0.788^**
8. Social Functioning	0.052	0.126	–0.020	0.100	0.346^*	0.549^**	0.561^**
9. Role Limitations – Emotional	–0.114	0.076	0.092	0.404^**	0.294	0.554^**	0.567^**	0.600^**
10. Role Limitations – Physical	–0.222	0.308	–0.019	0.332^*	0.302	0.397^*	0.354^*	0.522^**	0.691^**
11. General Health	–0.235	0.135	0.299	0.394^*	0.382^*	0.591^**	0.626^**	0.406^**	0.550^**	0.365^*
12. Physical Functioning	–0.304	–0.015	0.148	0.748^**	0.225	0.232	0.272	0.077	0.274	0.324^*	0.320^*

Note. ^* = Correlation is significant at the 0.05 level (2-tailed); ^** = Correlation is significant at the 0.01 level (2-tailed).

Additionally, paraplegia (vs. tetraplegia) was associated with higher HRQOL in the domains of energy, role limitations-emotional, role limitations-physical, general health, and physical functioning. Then, nearly all HRQOL variables were significantly related to each other with the exception of pain and role limitations-emotional, and pain and role limitations-physical. Physical functioning was also not significantly associated with pain, energy, mental health, social functioning, or role limitations-emotional.

3.2 Path model

A path model was developed using AMOS 21.0 to validate a hypothesized pattern of relations among variables leading from pain in individuals with SCI through energy, mental health and social functioning, and role limitations-emotional, to role limitations-physical. For this analysis, it was hypothesized that pain in individuals with SCI would a have direct and positive effect on energy. Energy was hypothesized to have a direct and positive effect on mental health and social functioning. Then it was hypothesized that both mental health and social functioning would have a direct and positive effect on role limitations-emotional, which would then have a direct and positive effect on role limitations-physical. Further, it was hypothesized that all indirect effects in this model would be statistically significant, resulting in a multiple mediational model from pain to role-limitations-physical.

The path model with factor loadings (standard regression weights) appears in Fig. 1.

Fig.1

Path model with standardized loadings. Note. d1-d5 = disturbance (error) terms 1–5.

The overall fit for the model was generally good, x²/df = 0.583, CFI = 1.00, GFI = 0.96, NFI = 0.96, IFI = 1.03, TLI = 1.06, AGFI = 0.90 and RMSEA = 0.00. As hypothesized, pain in individuals with SCI was positively associated with energy (p < 0.001); energy was positively associated with mental health (p < 0.001) and social functioning (p < 0.001); mental health (p = 0.020) and social functioning (p = 0.005) were positively associated with role limitations-emotional; and role limitations-emotional was positively associated with role limitations-physical (p < 0.001). Additionally, pain yielded a significant indirect effect on mental health through energy (β= 0.40, p = 0.001), as well as a significant indirect effect on social functioning through energy (β= 0.28, p = 0.002). Pain also exerted an indirect effect on role limitations-emotional through energy, mental health, and social functioning (β= 0.25, p = 0.001), as well as an overall indirect effect on role limitations-physical through all prior variables in the model (β= 0.17, p = 0.001), suggesting that all four variables significantly mediated the relationship between pain and physical disability.

4 Discussion

The purpose of this study was to construct and test a theoretical path model illuminating the HRQOL pathways through which pain may increase physical disability in individuals with SCI in a sample from Colombia, South America. It was hypothesized that increased pain would lead to decreased energy, which would lead to decreased mental health and social functioning, which both would lead to emotional role limitations, and finally to physical role limitations. The path model overall showed excellent fit indices, and each individual path within the model was statistically significant. Further, pain exerted significant indirect effects through all possible mediators in the model, ultimately suggesting that energy, mental health, social functioning, and role limitations-emotional were likely pathways through which pain exerted its effects on physical disability in individuals with SCI.

In the correlation matrix, an inverse relationship emerged between age and pain HRQOL, which is consistent with previous research on individuals with SCI finding that pain increases with age (Budh et al., 2003). The finding that individuals with paraplegia had higher HRQOL in the domains of energy, role limitations-emotional, role limitations-physical, general health, and physical functioning is not surprising, although some previous literature (Westgren & Levi, 1998), even using the same SF-36 scale as in the current study, has found that individuals with tetraplegia report lower physical functioning HRQOL than individuals with paraplegia, but similar levels of the other components of HRQOL. Perhaps this is because Westgren (1998) conducted their study in Sweden, which has a substantially more comprehensive rehabilitation accommodation infrastructure than Colombia, such that tetraplegia in Colombia may exert a greater toll on various aspects of HRQOL in individuals with tetraplegia.

The first part of the path model finding that pain in individuals with SCI was associated with lower energy is consistent with previous research showing a positive relationship between pain and fatigue among this population (Fawkes-Kirby, et al., 2008). Likely, higher pain can reduce the energy of individuals with SCI as most activities of daily living require more energy to be exerted when one is in pain. The second parts of the model finding that energy was positively associated with mental health and social functioning are also consistent with previous research showing that individuals with SCI who are highly fatigued exhibit more depressive symptoms (Dryden et al., 2005) and social isolation (Hammell, 1994). Reduced energy may make individuals with SCI less likely to want to engage in social interactions or in behaviors that they typically find pleasurable, which could decrease mental health.

The third parts of the path model finding that mental health and social functioning were positively associated with role limitation-emotional suggest that mental health problems, particularly when coupled with a lack of social engagement, can severely limit the work and other daily activities of individuals with SCI. The fourth part of the model finding that role limitation-emotional and role limitation-physical were positively associated conforms to patterns found in previous research showing that depression and self-reported physical health are closely related among individuals with SCI (Bombardier, Richards, Krause, Tulsky, & Tate, 2004). Indeed, role limitations in the daily activities of individuals with SCI due to mental health issues may channel directly into greater disability due to physical health problems.

Finally, pain yielded multiple indirect effects: on mental health and social functioning through energy, on role limitations-emotional through these previous variables, and on role-limitations-physical through all variables in the model. To the authors’ knowledge, this is the first study to date that has examined indirect effects in this series of events in order to link them in a theoretical causal chain; moreover, this has not been done among individuals with SCI in Latin America, where very little research on SCI has been conducted. This multiple mediational pattern is important because it uncovers and highlights several potential nodes for clinical intervention which if targeted in the context of rehabilitation or outpatient services, could result in salubrious direct and indirect effects reverberating down the theoretical causal chain and ultimately reducing physical disability in individuals with SCI.

Because all hypotheses in the current study were supported, the findings in conjunction have important implications for SCI intervention research in Colombia, as well as in other global regions. When pain is high in individuals with SCI, pain itself may be an important target for intervention research. Extensive research has documented the effectiveness of non-pharmacological cognitive-behavioral techniques for the management of chronic pain (Linton & Ryberg, 2001). Further, these programs have been modified specifically for the treatment of pain in SCI and include educational, cognitive, and behavioral approaches for dealing with neuropathic and other types of pain (Budh, Kowalski, & Lundeberg, 2006). Cognitive styles such as catastrophizing have been linked to pain intensity, psychological distress, and pain-related disability in individuals with SCI (Turner, Jensen, Warms, & Cardenas, 2002), so these maladaptive cognitions may be particularly ripe targets for cognitive-behavioral interventions. SCI rehabilitation programs would greatly benefit from incorporating pain-management approaches into their programming, as not treating pain may keep pain after SCI high and contribute to the cascade of negative effects found in the current study.

Rehabilitation clinicians may also benefit from attempting to help individuals with SCI improve their energy. Mindfulness-based stress reduction (MBSR) has been proven effective in increasing participants’ energy, as well as decreasing pain, and it involves helping bring awareness, calmness, and a sense of the present and of one’s body to participants (Smith et al., 2008). Other authors (Craig, Tran, Wijesuriya, & Middleton, 2012) have argued for comprehensive programs to target fatigue in individuals with SCI that include cognitive-behavioral approaches, exercise interventions, as well as training in the use of assistive technologies to reduce unnecessary energy expenditure.

The findings from the current study suggest that rehabilitation clinicians can also directly target psychosocial problems, such as reductions in mental health and social functioning, as well as the ways in which those reductions limit one’s daily activities. Social support is an extremely important resource in Latin America as well as in individuals with SCI in other global regions, as it has been shown to be associated with better psychological adjustment to SCI (Anson, Stanwyck, & Krause, 1993). Interventions that help increase participation in daily social activities and establish or strengthen a support network have the potential to improve social functioning and overall mental health in individuals with SCI. In the particular cultural context where this study was conducted in Colombia, the importance of family and community relationships cannot be understated, so helping individuals with SCI reconnect with their larger social networks is vital. For example, previous research has found that three types of social support (appraisal, belonging, and tangible) were all highly associated with reduced mental health problems among SCI caregivers in Latin America (Morlett-Paredes et al., 2014). Finally, there is evidence supporting the effectiveness of cognitive-behavioral therapy in decreasing depressive symptoms after SCI (Mehta et al., 2011) which should be a primary component of nearly all SCI rehabilitation.

4.1 Limitations and future directions

The current study has several limitations that should be taken into account which also present directions for future research. First, one of the main limitations was the convenience sampling method used which likely affected the representativeness of the sample and the generalizability of the findings. Participants were recruited from a non-profit organization in Colombia, and therefore the sample demographics reflect only a segment of the population of individuals with SCI in Latin America, so it is important to replicate this study and model in other communities throughout the region and globally.

A second limitation to the current study is the inference of a causal chain of psychosocial events in the path model from ultimately cross-sectional and correlational data. One of the main purposes of a path model is to make causal inference, but with cross-sectional data, an inference can only find support, not proof. Future research can more directly test the cascade supported in the current study with a cross-lagged panel, longitudinal design to more strongly infer causation.

A third limitation is that the index of bodily pain in the current study measured overall bodily pain-related quality of life, not neuropathic, musculoskeletal, radicular, or other pain that is specific to SCI. Future research on SCI populations would benefit from considering the influence of general pain such as that measured in this study versus pain that is more SCI-specific. Similarly, unfortunately data were not collected on the types of pain treatments that participants were contemporarily receiving, so no covariation could be performed based on current treatments, but this is an important variable to account for in future research.

Despite these limitations, the current study is the first to link pain in individuals with SCI to physical disability in a theoretical causal chain, finding mediational effects through fatigue, mental health, social functioning, and role limitation-emotional. This study also contributes to the extremely limited research literature on individuals with SCI in diverse global regions such as Latin America who are particularly at risk for negative outcomes given the lack of comprehensive rehabilitation infrastructures. Future research should attempt to use the patterns of connections uncovered in the current study to develop and test interventions that capitalize on multiple pathways for reducing physical disability in individuals with SCI.

Conflict of interest

The authors have no conflicts of interest to declare.

References

Alonso

, Prieto

, & Antó

J. M.

(1995). La versión española del SF-36 Health Survey (Cuestionario de Salud SF-36): Un instrumento para la medida de los resultados clínicos. Med Clin (Barc), 104, 771–776.

Anson

C. A.

, Stanwyck

D. J.

, & Krause

J. S.

(1993). Social support and health status in spinal cord injury. Spinal Cord, 31, 632–638.

Bombardier

C. H.

, Richards

J. S.

, Krause

J. S.

, Tulsky

, & Tate

D. G.

(2004). Symptoms of major depression in people with spinal cord injury: Implications for screening. Archives of Physical Medicine and Rehabilitation, 85, 1749–1756.

Budh

C. N.

, Kowalski

, & Lundeberg

(2006). A comprehensive pain management programme comprising educational, cognitive and behavioural interventions for neuropathic pain following spinal cord injury. Journal of Rehabilitation Medicine, 38, 172–180.

Budh

C. N.

, Lund

, Hultling

, Levi

, Werhagen

, Ertzgaard

, & Lundeberg

(2003). Gender related differences in pain in spinal cord injured individuals. Spinal Cord, 41, 122–128.

Byrne

B. M.

(2004). Structural equation modeling with EQS and EQS/Windows. Newbury Park: Sage.

Cao

, Chen

, & DeVivo

M. J.

(2011). Lifetime direct costs after spinal cord injury. Topics in Spinal Cord Injury Rehabilitation, 16, 10–16.

Craig

, Tran

, & Middleton

(2008). Psychological morbidity and spinal cord injury: A systematic review. Spinal Cord, 47, 108–114.

Craig

, Tran

, Siddall

, Wijesuriya

, Lovas

, Bartrop

, & Middleton

(2013). Developing a model of associations between chronic pain, depressive mood, chronic fatigue, and self-efficacy in people with spinal cord injury. Journal of Pain, 14, 911–920.

10.

Craig

, Tran

, Wijesuriya

, & Middleton

(2012). Fatigue and tiredness in people with spinal cord injury. Journal of Psychosomatic Research, 73, 205–210.

11.

Devivo

M. J.

, & Chen

(2011). Trends in new injuries, prevalent cases, and aging with spinal cord injury. Archives of Physical Medicine and Rehabilitation, 92, 332–338.

12.

Dryden

D. M.

, Saunders

L. D.

, Rowe

B. H.

, May

L. A.

, Yiannakoulias

, Svenson

L. W.

, … & Voaklander

D. C.

(2005). Depression following traumatic spinal cord injury. Neuroepidemiology, 25, 55–61.

13.

Fawkes-Kirby

T. M.

, Wheeler

M. A.

, Anton

H. A.

, Miller

W. C.

, Townson

A. F.

, & Weeks

C. A.

(2008). Clinical correlates of fatigue in spinal cord injury. Spinal Cord, 46, 21–25.

14.

Hammell

K. R.

(1994). Psychosocial outcome following spinal cord injury. Paraplegia, 32, 771–779.

15.

L. T.

, & Bentler

P. M.

(1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling: A Multidisciplinary Journal, 6, 1–55.

16.

Jensen

M. P.

, Chodroff

M. J.

, & Dworkin

R. H.

(2007). The impact of neuropathic pain on health-related quality of life: Review and implications. Neurology, 68, 1178–1182.

17.

Jensen

M. P.

, Hoffman

A. J.

, & Cardenas

D. D.

(2005). Chronic pain in individuals with spinal cord injury: A survey and longitudinal study. Spinal Cord, 43, 704–712.

18.

Jiménez

H. E.

, Fepafem . (2009). Trauma raquimedular. Fepafem. Guías para manejo de Urgencias. Retreived from: http://www.fepafem.org.ve/Guias_de_Urgencias/Trauma/Trauma_raquimedular.Pdf.

19.

Leduc

B. E.

, & Lepage

(2002). Health-related quality of life after spinal cord injury. Disability & Rehabilitation, 24, 196–202.

20.

Linton

S. J.

, & Ryberg

(2001). A cognitive-behavioral group intervention as prevention for persistent neck and back pain in a non-patient population: A randomized controlled trial. Pain, 90, 83–90.

21.

Lugo

L. H.

, García

H. I.

, & Montoya

J. G.

(2002). Perfil epidemiológico de la lesión medular en Medellín (Colombia) 1995-1999. Revista Colombiana de Medicina Física y Rehabilitacíon, 13, 26–38.

22.

Mariano

A. J.

(1992). Chronic pain and spinal cord injury. The Clinical Journal of Pain, 8, 87–92.

23.

Mehta

, Orenczuk

, Hansen

K. T.

, Aubut

J. A. L.

, Hitzig

S. L.

, Legassic

, & Teasell

R. W.

(2011). An evidence-based review of the effectiveness of cognitive behavioral therapy for psychosocial issues post-spinal cord injury. Rehabilitation Psychology, 56, 15.

24.

McColl

M. A.

, Arnold

, Charlifue

, Glass

, Savic

, & Frankel

(2003). Aging, spinal cord injury, and quality of life: Structural relationships. Archives of Physical Medicine and Rehabilitation, 84, 1137–1144.

25.

McDonald

J. W.

, & Sadowsky

(2002). Spinal-cord injury. The Lancet, 359, 417–425.

26.

Morlett-Paredes

, Perrin

P. B.

, Olivera

S. L.

, Rogers

H. L.

, Perdomo

J. L.

, Arango

J. A.

, & Arango-Lasprilla

J. C.

(2014). With a little help from my friends: Social support and mental health in SCI caregivers from Neiva, Colombia. Neuro Rehabilitation, 35, 841–849.

27.

National Institutes of Health. (2008). Spinal Cord Trauma. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/001066.htm

28.

National Institute of Neurological Disorders and Stroke. (2008), Spinal cord injury: Hope through research.

29.

National Spinal Cord Injury Statistical Center. (2011). Annual report of the Spinal Cord Injury Model Systems.

30.

National Spinal Cord Injury Statistical Center. (2013). Spinal cord injury facts and figures at a glance.

31.

Perry

K. N.

, Nicholas

M. K.

, & Middleton

(2009). Spinal cord injury-related pain in rehabilitation: A cross-sectional study of relationships with cognitions, mood and physical function. European Journal of Pain, 13, 511–517.

32.

Post

, & Noreau

(2005). Quality of life after spinal cord injury. Journal of Neurologic Physical Therapy, 29, 139–146.

33.

Rintala

D. H.

, Loubser

P. G.

, Castro

, Hart

K. A.

, & Fuhrer

M. J.

(1998). Chronic pain in a community-based sample of men with spinal cord injury: Prevalence, severity, and relationship with impairment, disability, handicap, and subjective well-being. Archives of Physical Medicine and Rehabilitation, 79, 604–614.

34.

Romero

, Jiménez

A. I.

, & Román

(1998). Rehabilitación en trauma raquimedular. Guías de práctica clínica basadas en la evidencia. Bogotá: Ascofame, Seguro Social.

35.

Siddall

P. J.

, & Loeser

J. D.

(2001). Pain following spinal cord injury. Spinal Cord, 39, 63–73.

36.

Smith

B. W.

, Shelley

B. M.

, Dalen

, Wiggins

, Tooley

, & Bernard

(2008). A pilot study comparing the effects of mindfulness-based and cognitive-behavioral stress reduction. Journal of Alternative and Complementary Medicine, 14, 251–258.

37.

Sommer

M. F.

(2001). Spinal cord injury. Functional rehabilitation. New Jersey: Prentice Hall.

38.

Spinal Cord Injury Network. (2009). Causes of Spinal Cord Injury. Retrieved from http://www.spinalinjury.net/causes-of-spinal-cord-injury.htm.

39.

Tabachnick

B. G.

, Fidell

L. S.

, & Osterlind

S. J.

(2001). Using multivariate statistics. New York: Pearson.

40.

Turner

J. A.

, Jensen

M. P.

, Warms

C. A.

, & Cardenas

D. D.

(2002). Catastrophizing is associated with pain intensity, psychological distress, and pain-related disability among individuals with chronic pain after spinal cord injury. Pain, 98, 127–134.

41.

Ware

J. E.

Jr , Sherbourne

C. D.

, (1992). The MOS 36-item short-form health survey (SF-36): I. Conceptual framework and item selection. Medical Care, 30, 473–483.

42.

Westgren

, & Levi

(1998). Quality of life and traumatic spinal cord injury. Archives of Physical Medicine and Rehabilitation, 79, 1433–1439.

43.

Widerström-Noga

E. G.

, Felipe-Cuervo

, & Yezierski

R. P.

(2001). Chronic pain after spinal injury: Interference with sleep and daily activities. Archives of Physical Medicine and Rehabilitation, 82, 1571–1577.

44.

Westgren

, & Levi

(1998). Quality of life and traumatic spinal cord injury. Archives of Physical Medicine and Rehabilitation, 79, 1433–1439.

45.

Wyndaele

, & Wyndaele

J. J.

(2006). Incidence, prevalence and epidemiology of spinal cord injury: What learns a worldwide literature survey? Spinal Cord, 44, 523–529.