Neither participants nor staff that had contact with participants was aware of condition assignment until the manipulation day. Participants attended daily visits to the laboratory on the 10 weekdays that followed the manipulation day Thursday through Friday; Monday through Friday; Monday through Wednesday and completed two weekend assessments during this time. Smoking status was tracked daily during this day follow-up interval; expired air CO was used to verify self-reported abstinence at all study points. Participants were thoroughly debriefed during the last follow-up. They had the option to attend eight group-based cognitive behavioral smoking cessation classes following their participation to assist them with their efforts at quitting smoking.
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Number of lifetime and past year 24 hour quit attempts, number of years smoked, and current daily smoking rate were assessed at baseline. We used the total scale factor score to assess nicotine dependence in this study e.
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Higher scores reflect greater levels of nicotine dependence. A five-item scale was used to assess craving at each study visit see Shiffman et al. Smoking status during each visit was determined by asking participants whether they had smoked since the last visit i.
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No participant who reported abstinence needed to be reclassified as a smoker based on the results of their CO assessment. Table 1 presents baseline characteristics between participants in the two conditions there were no significant differences between these randomized participants and the 95 individuals who were unable to maintain the 48 hour abstinence period on any of the variables in Table 1. Across conditions, participants were mostly similar, though participants in the no-lapse condition had significantly higher levels of nicotine dependence compared to participants in the lapse condition.
Several of these variables were included in later analyses as covariates to improve model fit and to control for possible selection imbalance. Everyone in the lapse group smoked two cigarettes confirmed by collecting the smoked cigarette butts and no one in the no lapse group smoked confirmed by researcher observation during the manipulation phase. Assessment of changes in expired air CO pre- to post-manipulation confirmed these observations: A 2 X 2 condition: We hypothesized that participants assigned to the lapse condition would relapse more quickly compared to participants in the no-lapse condition and that the effect of lapse on relapse would be mediated by post-lapse changes in craving.
The MacArthur approach was proposed specifically as a way to test mediation in the context of randomized clinical trials in which alternate treatment conditions may affect mediators and thus outcomes differently depending on condition. Although the current study is not a clinical trial, the logic of the approach for testing mediation is the same.
That is, we expected that inducing a lapse among participants in the lapse condition would cause changes in craving that would in turn hasten relapse. Among participants in the no lapse condition, we expected craving to follow its natural course given that we did not intervene to affect it. The key assumptions underlying the MacArthur approach are that the independent variable temporally precedes the mediating variable and that the independent variable causally impacts the mediator.
Under these assumptions, a statistically significant interaction between the independent variable and the mediator is interpreted as evidence of mediation for additional details on this approac, see Kraemer et al. The first question we addressed was whether participants in the lapse condition relapsed more quickly than participants in the no lapse condition.
We used Cox proportional hazards analysis Cox regression to model time to relapse, with number of days post-manipulation as the time scale. The first opportunity participants had to relapse i. Thus, in our Cox regression model, we defined Day 0 as the period from the baseline session to the end of the post-manipulation assessment. Day 1 was defined as any time after the post-manipulation assessment on the day of the manipulation Wednesday up until the point of assessment the following day Thursday.
Day 2 covered the period from the first follow-up assessment Thursday to the second Friday , and so on through Day Time to relapse was defined as the number of measurement occasions days between day 0 and relapse. Relapse was defined using a standard definition of seven consecutive days of smoking at least one cigarette each day Hughes et al.
In other words, participants who had not begun smoking by the ninth day post-manipulation were no longer at risk of being observed to relapse in our study due to the day length of the observation period and were therefore censored on that day. Censoring is a common feature of time-to-event data, which, if ignored, can lead to substantial bias in the analysis. Survival analysis properly takes censoring into account Selvin, Table 2 displays the results for this analysis.
Figure 1 displays the unadjusted survival function for participants in the lapse and no lapse conditions. These results clearly show that an increased risk of relapse decrease in time to relapse among those in the lapse condition compared to those in the no lapse condition.
The next question we sought to answer was whether participants in the lapse condition were more likely to experience changes in craving compared with those in the no lapse condition. Thus, in the model, change in craving is a time-varying outcome and each participant contributes as many observations to the model as he or she had post-manipulation days up to 9 without relapsing i. Preliminary analysis suggested that the relationship between relapse condition and craving change was not linear. To account for the non-linearity in the association, we recoded craving change into an ordinal scale.
The ordinal scale was a good fit to the data and there were enough observations at each level of the ordinal scale on which to base meaningful inferences. We categorized change in craving at each measurement occasion post-baseline as a decreasing if craving was at least 1 point less than baseline craving, b stable if craving was within 1 point in either direction of baseline craving, and c increasing if craving was at least 1 point greater on the 8-point craving scale than baseline craving.
This coding of the craving outcome allowed us to use ordinal logistic regression to test the association between study condition and change in craving. In the ordinal logistic model, we used the following values to represent these categories: The stable craving group was used as the reference group.
Standard errors for model coefficients were adjusted to account for clustering of observations within participants using the Huber-White sandwich estimator, a variance estimation approach implemented in the Surveylogistic procedure in SAS. Table 3 displays the results of this model. Compared with participants in the no lapse condition, participants in the lapse condition had 1.
Because these analyses control for baseline craving levels through the pre-lapse period, the results establish an episodic surge in craving after a lapse i. The final question we sought to answer was whether increased craving experienced by those in the lapse condition explained mediated their increased risk of relapse.
To test this hypothesis, we estimated a second Cox regression model in which we evaluated the joint effect of study condition and change in craving from baseline to the day before relapse on relapse i. This model included all of the predictors from the initial Cox regression model plus change in craving, which was treated as a time-varying covariate and had three levels decreasing, stable, and increasing as defined above. We modeled the joint effect of condition and change in craving by categorizing participants into conjoint levels of the two characteristics with dummy variables i.
Table 4 displays the results for this model. Thus, an episodic surge in craving significantly increased the likelihood of relapse but only among participants in the lapse condition. The results of the current study, in combination with the results of other experimental studies Chornock et al. The current study goes beyond these previous studies in that it provides new information about mediating mechanisms that link smoking lapses to relapses.
Compared with participants in the no lapse condition, participants who were assigned to lapse experienced an initial acute decrease in craving followed by a significant surge in craving. The surges in craving experienced by those in the lapse condition, which were observed after controlling for their baseline craving levels, explained their faster rate of relapse relative to participants in the control condition. The field of tobacco control has long struggled to understand why smoking lapses nearly always lead to relapses. As a result, cognitive-behavioral and pharmacological interventions have had little success in helping smokers to avoid relapse.
Research that clearly identifies the mechanisms that govern the relationship between lapse and relapse would have a substantial impact on smoking cessation and relapse prevention treatments, pointing the way toward the development of new treatments and modification of existing ones to target those mechanisms for change Shiffman, Our results therefore have implications for relapse prevention treatments in addition to having implications for theories that explain why lapses almost inevitably lead to relapses.
Cognitive-behavioral treatments Brown, and medications for smoking cessation Shiffman et al.
The results of this study suggest that cognitive-behavioral treatment efforts could, instead, focus on helping smokers prepare for and manage episodic increases in craving that follow lapses. For example, cognitive-behavioral craving management strategies such as relaxation or guided imagery, or cognitive restructuring to manage cue provoked cravings after smokers quit see Brown, could be included in advice to smokers on how to manage increases in craving that follow a lapse.
Medications like the nicotine patch are ineffective at blunting episodic surges of craving that result from exposure to smoking cues Tiffany et al. Of course, these suggestions would need to be evaluated in controlled clinical trials to ensure safety and efficacy.
The study results are neither fully consistent with negative reinforcement models Baker et al. The initial craving relief experienced by participants in the lapse condition is predicted by negative reinforcement models see Juliano et al. However, the subsequent increases in craving participants experienced between the programmed lapse and relapse, and the finding that this increase was related to subsequent relapse, are more consistent with reinstatement models than with negative reinforcement models see Shiffman et al.
Though not consistent with either theory individually, the findings are broadly consistent with the nicotine regulation model of smoking reviewed in Benowitz et al. According to the nicotine regulation model, smoking will alleviate craving related to nicotine deprivation i. Once nicotine has been metabolized and blood levels begin to drop, craving will re-emerge motivating the person to smoke again i. These rises and falls in levels of nicotine and corresponding changes in craving are hypothesized to maintain long-term patterns of smoking.
Additional research is needed to further refine the conceptual explanations that best account for the role that craving plays in explaining the link between smoking lapse and relapse. There are limitations to this study. First, the generalizability of the study is limited given that the sample was composed of reactively recruited, healthy, and heavier smokers. Third, we inferred the motivational effect of increased craving but did not assess the affective qualities of craving. Fourth, the lapse was experimentally-induced; although this represents a strength from a causal inference standpoint, whether the results generalize to an actual non-programmed lapse is not known.
Finally, although we observed significant levels of relapse, we only followed participants for 14 days after the experimentally manipulated lapse. In general, a majority of relapses occur within a two week window of quitting Shiffman et al. Nonetheless, a longer follow-up period would have provided a richer source of data.
These limitations notwithstanding, this study fills an important gap in the smoking literature by illuminating the relationship between lapse and relapse and specifying a new, mediating role for craving in the relapse process. The study is distinguished by its use of an experimental design to examine these questions in a way that enhanced the clinical utility and applicability of the model and findings.
As such, these results have implications for modifying the treatment protocols for existing cognitive-behavioral and pharmacological treatments designed to help smokers prevent lapses from becoming relapses. For all intents and purposes, days to first smoking and days to relapse are indistinguishable in our data. National Center for Biotechnology Information , U. Author manuscript; available in PMC Sep 1. Shadel , Steven C. Correspondence concerning this paper may be addressed to: The publisher's final edited version of this article is available at Health Psychol.
See other articles in PMC that cite the published article. Abstract Objectives Nearly all smokers who lapse experience a full blown relapse, but the mediating mechanisms that contribute to this relationship are not well understood. Conclusions Previously abstinent smokers who lapse are at risk for increased cigarette cravings and consequently, full-blown relapse.
Smoking cessation, relapse, craving.
Spinal cord injury - Wikipedia
Procedures Overview Total length of participation in the study was 20 consecutive days. Baseline session Participants attended a baseline session on a Friday, during which all aspects of the study were described to them, including that they could be assigned to a study condition in which they would be asked to smoke two cigarettes after quitting the lapse condition.
Manipulation day Wednesday was designated as the manipulation day.
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Smoking and quitting history Number of lifetime and past year 24 hour quit attempts, number of years smoked, and current daily smoking rate were assessed at baseline. Craving A five-item scale was used to assess craving at each study visit see Shiffman et al. Smoking status Smoking status during each visit was determined by asking participants whether they had smoked since the last visit i. Results Descriptive Characteristics of Randomized Participants Table 1 presents baseline characteristics between participants in the two conditions there were no significant differences between these randomized participants and the 95 individuals who were unable to maintain the 48 hour abstinence period on any of the variables in Table 1.
Spinal cord injury
Table 1 Baseline characteristics between participants in the two conditions. Open in a separate window. Manipulation Check Everyone in the lapse group smoked two cigarettes confirmed by collecting the smoked cigarette butts and no one in the no lapse group smoked confirmed by researcher observation during the manipulation phase. Mediation Analyses We hypothesized that participants assigned to the lapse condition would relapse more quickly compared to participants in the no-lapse condition and that the effect of lapse on relapse would be mediated by post-lapse changes in craving.
Effect of lapse on time to relapse The first question we addressed was whether participants in the lapse condition relapsed more quickly than participants in the no lapse condition. Effect of lapse on change in craving The next question we sought to answer was whether participants in the lapse condition were more likely to experience changes in craving compared with those in the no lapse condition.
Effect of lapse and changes in craving on time to relapse The final question we sought to answer was whether increased craving experienced by those in the lapse condition explained mediated their increased risk of relapse. Discussion The results of the current study, in combination with the results of other experimental studies Chornock et al. Acknowledgments This research was supported by R01CA Footnotes 1 Copies of the informed consent document are available by request to the first author.
Contributor Information William G. Integrating individual and public health perspectives. Annual Review of Addictions: The motivation to use drugs: A section of skin innervated through a specific part of the spine is called a dermatome , and injury to that part of the spine can cause pain, numbness, or a loss of sensation in the related areas. Paraesthesia , a tingling or burning sensation in affected areas of the skin, is another symptom.
The muscles may contract uncontrollably spasticity , become weak , or be completely paralysed. Spinal shock , loss of neural activity including reflexes below the level of injury, occurs shortly after the injury and usually goes away within a day. The specific parts of the body affected by loss of function are determined by the level of injury. The effects of injuries at or above the lumbar or sacral regions of the spinal cord lower back and pelvis include decreased control of the legs and hips , genitourinary system , and anus.
People injured below level L2 may still have use of their hip flexor and knee extensor muscles. It is common to experience sexual dysfunction after injury , as well as dysfunction of the bowel and bladder, including fecal and urinary incontinence. In addition to the problems found in lower-level injuries, thoracic chest height spinal lesions can affect the muscles in the trunk.
Injuries at the level of T1 to T8 result in inability to control the abdominal muscles. Trunk stability may be affected; even more so in higher level injuries. Injuries from T9 to T12 result in partial loss of trunk and abdominal muscle control. Thoracic spinal injuries result in paraplegia , but function of the hands, arms, and neck are not affected. One condition that occurs typically in lesions above the T6 level is autonomic dysreflexia AD , in which the blood pressure increases to dangerous levels, high enough to cause potentially deadly stroke.
Other autonomic functions may also be disrupted. For example, problems with body temperature regulation mostly occur in injuries at T8 and above. Spinal cord injuries at the cervical neck level result in full or partial tetraplegia also called quadriplegia. Additional signs and symptoms of cervical injuries include low heart rate , low blood pressure , problems regulating body temperature , and breathing dysfunction.
Complications of spinal cord injuries include pulmonary edema , respiratory failure , neurogenic shock , and paralysis below the injury site. In the long term, the loss of muscle function can have additional effects from disuse, including atrophy of the muscle. Immobility can lead to pressure sores , particularly in bony areas, requiring precautions such as extra cushioning and turning in bed every two hours in the acute setting to relieve pressure.
People with SCI are at especially high risk for respiratory and cardiovascular problems, so hospital staff must be watchful to avoid them. Another potentially deadly threat to respiration is deep venous thrombosis DVT , in which blood forms a clot in immobile limbs; the clot can break off and form a pulmonary embolism , lodging in the lung and cutting off blood supply to it. Urinary tract infection UTI is another risk that may not display the usual symptoms pain, urgency and frequency ; it may instead be associated with worsened spasticity.
Spinal cord injuries are most often caused by physical trauma. In the US, Motor vehicle accidents are the most common cause of SCIs; second are falls , then violence such as gunshot wounds, then sports injuries. SCI can also be of a nontraumatic origin. Vehicle-related SCI is prevented with measures including societal and individual efforts to reduce driving under the influence of drugs or alcohol, distracted driving , and drowsy driving. A person's presentation in context of trauma or non-traumatic background determines suspicion for a spinal cord injury.
The features are namely paralysis, sensory loss, or both at any level. Other symptoms may include incontinence. A radiographic evaluation using an X-ray , CT scan, or MRI can determine if there is damage to the spinal column and where it is located. Neurological evaluations to help determine the degree of impairment are performed initially and repeatedly in the early stages of treatment; this determines the rate of improvement or deterioration and informs treatment and prognosis.
The first stage in the management of a suspected spinal cord injury is geared toward basic life support and preventing further injury: A rigid cervical collar is applied to the neck, and the head is held with blocks on either side and the person is strapped to a backboard. The use of a cervical collar has been shown to increase mortality in people with penetrating trauma and is thus not routinely recommended in this group. Modern trauma care includes a step called clearing the cervical spine , ruling out spinal cord injury if the patient is fully conscious and not under the influence of drugs or alcohol, displays no neurological deficits, has no pain in the middle of the neck and no other painful injuries that could distract from neck pain.
If an unstable spinal column injury is moved, damage may occur to the spinal cord. SCI can impair the body's ability to keep warm, so warming blankets may be needed. Initial care in the hospital, as in the prehospital setting, aims to ensure adequate airway, breathing, cardiovascular function, and spinal motion restriction. If the systolic blood pressure falls below 90 mmHg within days of the injury, blood supply to the spinal cord may be reduced, resulting in further damage. The corticosteroid medication methylprednisolone has been studied for use in SCI with the hope of limiting swelling and secondary injury.
Surgery may be necessary, e. SCI patients often require extended treatment in specialized spinal unit or an intensive care unit. Usually the inpatient phase lasts 8—12 weeks and then the outpatient rehabilitation phase lasts 3—12 months after that, followed by yearly medical and functional evaluation. For people whose injuries are high enough to interfere with breathing, there is great emphasis on airway clearance during this stage of recovery. Physical therapy treatment for airway clearance may include manual percussions and vibrations, postural drainage ,  respiratory muscle training, and assisted cough techniques.
The amount of functional recovery and independence achieved in terms of activities of daily living, recreational activities, and employment is affected by the level and severity of injury. Weak joints can be stabilized with devices such as ankle-foot orthoses AFOs and knee-AFOs, but walking may still require a lot of effort. Spinal cord injuries generally result in at least some incurable impairment even with the best possible treatment.
The best predictor of prognosis is the level and completeness of injury, as measured by the ASIA impairment scale. A person with a mild, incomplete injury at the T5 vertebra will have a much better chance of using his or her legs than a person with a severe, complete injury at exactly the same place. One important predictor of motor recovery in an area is presence of sensation there, particularly pain perception. Sexual dysfunction after spinal injury is common. Problems that can occur include erectile dysfunction , loss of ability to ejaculate , insufficient lubrication of the vagina, and reduced sensation and impaired ability to orgasm.
Although life expectancy has improved with better care options, it is still not as good as the uninjured population. The higher the level of injury, and the more complete the injury, the greater the reduction in life expectancy. Breakdown of age at time of injury in the US from — Worldwide, the number of new cases since of SCI ranges from Males account for four out of five traumatic spinal cord injuries. SCI has been known to be devastating for millennia; the ancient Egyptian Edwin Smith Papyrus from BC, the first known description of the injury, says it is "not to be treated".
In a surgeon named Andre Louis removed a bullet from the lumbar spine of a patient, who regained motion in the legs. Scientists are investigating various avenues for treatment of spinal cord injury. Therapeutic research is focused on two main areas: Stem cell transplantation is an important avenue for SCI research: Six-month data is expected in January Another type of approach is tissue engineering, using biomaterials to help scaffold and rebuild damaged tissues. One avenue being explored to allow paralyzed people to walk and to aid in rehabilitation of those with some walking ability is the use of wearable powered robotic exoskeletons.
Preliminary studies of epidural spinal cord stimulators for motor complete injuries have demonstrated some improvement. From Wikipedia, the free encyclopedia. Spinal cord injury MRI of fractured and dislocated neck vertebra that is compressing the spinal cord Specialty Neurosurgery Types Complete, incomplete  Diagnostic method Based on symptoms, medical imaging  Treatment Spinal motion restriction , intravenous fluids , vasopressors  Frequency c. X-rays left are more available, but can miss details like herniated disks that MRIs can show right.
Rehabilitation in spinal cord injury. Spinal cord injury research. American College of Surgeons. Retrieved 16 May Reggie; Turner, Dennis A. Archived from the original on European Review for Medical and Pharmacological Sciences. Archived PDF from the original on National Institutes of Health. The journal of spinal cord medicine. Archived from the original on June 18, Retrieved 5 November Archives of Physical Medicine and Rehabilitation. Journal of Neurology, Neurosurgery, and Psychiatry. Broad-based clinical practice intervention and practical application".
The Journal of Spinal Cord Medicine. Annals of the New York Academy of Sciences. A foundation for best medical practice". The contribution of men's adherence to scripts for sexual potency". Br J Health Psychol. Journal of Controlled Release. A review of the factors influencing walking recovery after spinal cord injury". Frontiers in Human Neuroscience. A multicenter retrospective study". Towards a living data repository". A systematic review of the literature and evidence-based guidelines". Physical Rehabilitation 5th ed. The Journal of Rehabilitation Research and Development.
Journal of Rehabilitation Research and Development. Progress, Promise, and Priorities.