The power of language: Functional brain network topology of deaf and hearing in relation to sign language experience.

Prolonged auditory sensory deprivation leads to brain reorganization. This is indicated by functional enhancement in remaining sensory systems and known as cross-modal plasticity. In this study we investigated differences in functional brain network topology between deaf and hearing individuals. We also studied altered functional network responses between deaf and hearing individuals with a recording paradigm containing an eyes-closed and eyes-open condition. Electroencephalography activity was recorded in a group of sign language-trained deaf (N = 71) and hearing people (N = 122) living in rural Africa. Functional brain networks were constructed from the functional connectivity between fourteen electrodes distributed over the scalp. Functional connectivity was quantified with the phase lag index based on bandpass filtered epochs of brain signal. We studied the functional connectivity between the auditory, somatosensory and visual cortex and performed whole-brain minimum spanning tree analysis to capture network backbone characteristics. Functional connectivity between different regions involved in sensory information processing tended to be stronger in deaf people during the eyes-closed condition in both the alpha and beta frequency band. Furthermore, we found differences in functional backbone topology between deaf and hearing individuals. The backbone topology altered during transition from the eyes-closed to eyes-open condition irrespective of deafness, but was more pronounced in deaf individuals. The transition of backbone strength was different between individuals with congenital, pre-lingual or post-lingual deafness. Functional backbone characteristics correlated with the experience of sign language. Overall, our study revealed more insights in functional network reorganization caused by auditory deprivation and cross-modal plasticity. It further supports the idea of a brain plasticity potential in deaf and hearing people. The association between network organization and acquired sign language experience reflects the ability of ongoing brain adaptation in people with hearing disabilities.

Health-based risk neutralization in private disability insurance.

BACKGROUND: Exclusions are used by insurers to neutralize higher than average risks of sickness absence (SA). However, differentiating risk groups according to one's medical situation can be seen as discrimination against people with health problems in violation of a 2006 United Nations convention. The objective of this study is to investigate whether the risk of SA of insured persons with exclusions added to their insurance contract differs from the risk of persons without exclusions. METHODS: A dynamic cohort of 15 632 applicants for private disability insurance at a company insuring only college and university educated self-employed in the Netherlands. Mean follow-up was 8.94 years. Duration and number of SA periods were derived from insurance data to calculate the hazard of SA periods and of recurrence of SA periods. RESULTS: Self-employed with an exclusion added to their insurance policy experienced a higher hazard of one or more periods of SA and on average more SA days than self-employed without an exclusion. CONCLUSION: Persons with an exclusion had a higher risk of SA than persons without an exclusion. The question to what extent an individual should benefit from being less vulnerable to disease and SA must be addressed in a larger societal context, taking other aspects of health inequality and solidarity into account as well.

Indications of a Scarring Effect of Sickness Absence Periods in a Cohort of Higher Educated Self-Employed.

OBJECTIVES: Little is known regarding incidence and recurrence of sickness absence in self-employed. The primary aim of this study was to evaluate the influence of the number of prior episodes of sickness absence on the risk of subsequent periods of sickness absence in higher educated self-employed. METHODS: In a historic register study based on the files of a Dutch private disability insurance company all sickness absence periods of 30 days or more were analysed. RESULTS: A total of 15,868 insured persons contributed 141,188 person years to the study. In total, 5608 periods of sickness absence occurred during follow-up. The hazard of experiencing a new period of sickness absence increased with every previous period, ranging from a hazard ratio of 2.83 in case of one previous period of sickness absence to a hazard ratio of 6.72 in case of four previous periods. This effect was found for both men and women and for all diagnostic categories of the first period of sickness absence. CONCLUSIONS: Our study shows that for all diagnostic categories the hazard of experiencing a recurrence of sickness absence is appreciably higher than for experiencing a first episode. This suggests that this increased hazard may be related to the occurrence of sickness absence itself rather than related to characteristics of the insured person or of the medical condition. These findings could indicate that sickness absence periods may have a scarring effect on the self-employed person experiencing the sickness absence.

Predictors of recurrent sickness absence due to depressive disorders--a Delphi approach involving scientists and physicians.

BACKGROUND: Depression is a common and highly recurrent mental disorder that is accompanied by poor functioning at home and at work. Not all depressed employees report sick and little is known about variables associated with sickness absence (SA) due to depression. Recurrent SA due to depression tends to marginalize employees from the workforce and exclude them from social participation. Therefore, this study sought group consensus on factors predicting recurrent SA due to depression. METHODOLOGY/PRINCIPAL FINDINGS: 23 scientists in the field of work and mental health and 23 physicians with expertise in assessing work disability were invited for a Delphi study. Sixty-seven factors retrieved from the literature were scored for their impact on the recurrence of SA due to depression, range 1 (no impact) to 10 (very high impact) in two Delphi rounds. The third Delphi round addressed the assessability and modifiability of elected predictors. Group consensus was defined as 75% agreement. In the first round (response 78%), group consensus was reached on a high impact of 13 factors on recurrent SA due to depression. The second round (response 79%) added another 8 factors with high impact on recurrent SA due to depression. The panelists were of the opinion that stressful life and work events, age at first diagnosis, duration of the last depressive episode, anxiety, lifetime number of depressive episodes, and psychological work demands were readily assessable in consultation with patients. Furthermore, work factors, particularly decision latitude, psychological job demands, and commitment to work, were recognized as modifiable. CONCLUSIONS/SIGNIFICANCE: Although results have to be validated with further quantitative research, physicians may identify employees at risk of recurrent SA due to depression and may support them to adjust their work aimed at increasing commitment to work and preventing future SA due to depression.

Potential processes involved in the initiation and maintenance of whiplash-associated disorders: discussion paper 3.

STUDY DESIGN: Nonsystematic review and discussion of the etiological processes involved in whiplash-associated disorders (WAD). OBJECTIVE: To summarize the research and identify priorities for future research. SUMMARY OF BACKGROUND DATA: Although there is convergent evidence of a peripheral lesion in some individuals after whiplash injury, in the majority of injured people, a lesion cannot be established with current imaging technology. Therefore, it is important to consider processes that underlie the initiation and maintenance of whiplash pain as this may allow for the development and testing of interventions to target these processes and improve outcomes. METHODS: A nonsystematic review was performed to summarize current knowledge regarding potential etiological processes involved in the initiation and maintenance of WAD and to identify future research priorities. RESULTS: There are several etiological processes potentially involved in the initiation and maintenance of WAD. These include augmented nociceptive processing, stress system responses, and psychosocial and sociocultural factors. Recent findings also indicate that morphological changes in the neck muscles of injured people show some association with poor recovery, but the mechanisms underlying these changes are not clear. Preliminary evidence indicates associations between these processes. Future research priorities include the following: more sophisticated investigation and analysis of interactions between the various processes; whether the modification of these processes is achievable and if modification can improve health outcomes; and to clarify factors involved in the initiation of whiplash pain versus those involved in symptom maintenance. CONCLUSION: Research to date indicates that there are several physiological and psychological etiological processes that may underlie the initiation and maintenance of whiplash-related pain and disability. Further research is required to determine relationships and interactions between these factors and to determine whether their modification is possible and will improve outcomes after injury.

Fear avoidance and illness beliefs in post-traumatic neck pain.

STUDY DESIGN: A descriptive overview of the relevant literature and the introduction of a new psychological model. OBJECTIVE: The fear-avoidance (FA) model and the potential importance of illness beliefs in post-traumatic neck pain are discussed. The causal beliefs-anxiety model is introduced as an adaptation of the FA model, emphasizing the critical role of illness beliefs. SUMMARY OF BACKGROUND DATA: Although the FA model is most thoroughly used to investigate chronic low back pain, it seems also highly relevant as a starting point for other chronic pain conditions like whiplash. Kinesophobia and pain catastrophizing form critical components of the FA model. It has been shown that breaking the FA cycle by affecting the critical components of the model may be an effective method to prevent the development of chronicity. METHODS: By using the FA model as a starting point, we present the causal beliefs-anxiety model and argue how this might help explain chronic whiplash symptoms and might provide clues for preventive interventions. RESULTS: On experiencing muscular neck pain, catastrophizing may give rise to dysfunctional illness beliefs regarding the cause of this pain. The illness identity and other beliefs feed symptom expectation and attribution, as well as expectations regarding the course of muscular neck pain. These negative expectations can contribute to a less favorable outcome or may even cause symptoms. Therefore, it seems important to integrate the alleged role of illness beliefs in an adapted FA model, the "causal beliefs-anxiety model." CONCLUSION: In clinical practice, it seems important to have insight into the patient's illness beliefs about the cause of the experienced symptoms. Health care professionals should be aware of the possible detrimental influence of dysfunctional illness beliefs. In the early stage, adequate explanation and information about the probable course may be sufficient to prevent the generation of dysfunctional illness beliefs thereby preventing the development of a chronic course. At the population level, educational campaigns that inform people about probable causes and realistic expectations regarding post-traumatic neck pain could provide an effective strategy for preventing chronic whiplash symptoms.

Complexities in understanding the role of compensation-related factors on recovery from whiplash-associated disorders: discussion paper 2.

STUDY DESIGN: Focused discussion. OBJECTIVE: To present some of the complexities in conducting research on the role of compensation and compensation-related factors in recovery from whiplash-associated disorders (WAD) and to suggest directions for future research. SUMMARY OF BACKGROUND DATA: There is divergence of opinion, primary research findings, and systematic reviews on the role of compensation and/or compensation-related factors in WAD recovery. METHODS: The topic of research of compensation/compensation-related factors was discussed at an international summit meeting of 21 researchers from diverse fields of scientific enquiry. This article summarizes the main points raised in that discussion. RESULTS: Traffic injury compensation is a complex sociopolitical construct, which varies widely across jurisdictions. This leads to conceptual and methodological challenges in conducting and interpreting research in this area. It is important that researchers and their audiences be clear about what aspect of the compensation system is being addressed, what compensation-related variables are being studied, and what social/economic environment the compensation system exists in. In addition, summit participants also recommended that nontraditional, sophisticated study designs and analysis strategies be employed to clarify the complex causal pathways and mechanisms of effects. CONCLUSION: Care must be taken by both researchers and their audiences not to overgeneralize or confuse different aspects of WAD compensation. In considering the role of compensation/compensation-related factors on WAD and WAD recovery, it is important to retain a broad-based conceptualization of the range of biological, psychological, social, and economic factors that combine and interact to define and determine how people recover from WAD.

Relationship between posttraumatic stress disorder symptoms and the course of whiplash complaints.

OBJECTIVE: This study investigates the relationship between posttraumatic stress disorder (PTSD) symptoms (avoidance, reexperiencing, and hyperarousal) and the presence, severity, and duration of neck complaints after motor vehicle accidents. METHODS: Individuals who had been involved in traffic accidents and had initiated compensation claim procedures with a Dutch insurance company were sent questionnaires (Q1) containing complaint-related questions and the Self-Rating Scale for PTSD. Of the 997 questionnaires that were dispatched, 617 (62%) were returned. Only car accident victims were included in this study (n=240). Complaints were monitored using additional questionnaires that were administered 6 months (Q2) and 12 months (Q3) after the accident. RESULTS: PTSD was related to the presence and severity of concurrent post-whiplash syndrome. More specifically, the intensity of hyperarousal symptoms that were related to PTSD at Q1 was found to have predictive validity for the persistence and severity of post-whiplash syndrome at 6 and 12 months follow-up. CONCLUSION: Results are consistent with the idea that PTSD hyperarousal symptoms have a detrimental influence on the recovery and severity of whiplash complaints following car accidents.

Can kinesiophobia predict the duration of neck symptoms in acute whiplash?

OBJECTIVES: In low back pain, clinical studies suggest that kinesiophobia (fear of movement/(re)injury) is important in the etiology of chronic symptoms. In this prospective cohort study, the predictive role of kinesiophobia in the development of late whiplash syndrome was examined. METHODS: Victims of car collisions with neck symptoms who initiated compensation claim procedures with a Dutch insurance company were sent a questionnaire containing symptom-related questions and the Tampa Scale of Kinesiophobia (TSK-DV). Follow-up questionnaires were administered 6 and 12 months after the collision. Survival analysis was used to study the relationship between the duration of neck symptoms and explanatory variables. RESULTS: Of the 889 questionnaires sent, 590 (66%) were returned and 367 used for analysis. The estimated percentage of subjects with neck symptoms persisting 1 year after the collision was 47% (SE 2.7%). In a regression model without symptom-related variables, kinesiophobia was found to be related to a longer duration of neck symptoms (P=0.001). However, when symptom-related information was entered into the model, the effect of kinesiophobia did not reach statistical significance (P=0.089). CONCLUSIONS: Although a higher score on the TSK-DV was found to be associated with a longer duration of neck symptoms, information on early kinesiophobia was not found to improve the ability to predict the duration of neck symptoms after motor vehicle collisions.