Vera Neumann

Construct validity and reliability of the Rivermead Post-Concussion Symptoms Questionnaire

Objectives: To provide further evidence of reliability and internal and external construct validity of the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), which measures severity of postconcussion symptoms following head injury. Design and setting: A cross-sectional study of consecutive patients presenting with a head injury in two urban teaching hospitals and a community trust. Patients: Three hundred and sixty-nine patients returned a questionnaire from 1689 consecutive adult patients (18 years and above) referred to radiology for a skull X-ray following a head injury, and those who were currently under the care of a community-based multidisciplinary head injury team. Method: Internal construct validity tested by fit to the Rasch Measurement model; external construct validity tested by correlations with Rivermead Head Injury Follow-up Questionnaire (RHFUQ); test-retest reliability tested by correlations at two-week intervals. Outcome measures: Rivermead Post-Concussion Symptoms Questionnaire and Rivermead Head Injury Follow-up Questionnaire. Main results: RPQ scores ranged from 0 to 64 (17.3% floor, 0.3% ceiling). Overall fit to the Rasch model was poor (item fit mean-0.416, SD=1.989, chi-squared=172.486, p < 0.01) suggesting a lack of unidimensionality. The items headaches, dizziness and forgetful displayed misfitting residuals and the first two items also displayed significant item trait fit statistics (p < 0.0006). After removing the items headaches, dizziness and subsequently nausea the RPQ demonstrated good fit at overall and individual item levels, both for the remaining 13 items (RPQ-13) and the three items (RPQ-3) which now formed a subsidiary scale. All items functioned consistently across age and gender. The RPQ-13 and RPQ-3 scales showed test-retest reliability coefficients of 0.89 and 0.72 (both p-values < 0.01) and positive correlations with RHFUQ scores (0.83 for RPQ-13, 0.62 for RPQ-3, both p-values< 0.01). Conclusions: As currently used, the RPQ does not meet modern psychometric standards. Its 16 items do not tap into the same underlying construct and should not be summated in a single score. When the RPQ is split into two separate scales, the RPQ-13 and the RPQ-3, each set of items forms a unidimensional construct for people with head injury at three months post injury. These scales show good test-retest reliability and adequate external construct validity.

Mood disorders following traumatic brain injury: identifying the extent of the problem and the people at risk

The extent of mood disorders following traumatic brain injury (TBI), and the possible risk factors, are investigated. New data are presented from a prospective study of consecutive hospital admissions. Six months post-TBI, 99 adults completed a standardized assessment of emotional state, the Wimbledon Self-Report Scale. Cognitive performance and the impact of the injury on everyday functioning were also assessed. The rate of clinically significant mood disorders (caseness) was 38%. Of the demographic or injury characteristics, only pre-injury occupational status predicted post-injury caseness. Those unoccupied pre-injury were more likely to report mood disturbance post-injury. In contrast, post-injury occupational status was not related to caseness either for the whole group or the subgroup of those previously occupied, despite the adverse effects on occupational functioning for a significant proportion of subjects. Associations were found between emotional state and cognitive and everyday functioning 6 months post-injury. Psychosocial disabilities appeared more strongly associated to mood disorders than did physical disabilities. A significant level of unmet need has been highlighted, and possible risk factors identified, which may inform the purchase and provision of TBI rehabilitation services. Follow-up data on these subjects are available and will be reported separately.

Screening for job loss: Development of a work instability scale for traumatic brain injury

Objective: The objective of this study was to explore the concept of work instability (a mis-match between an individuals functional and cognitive abilities and the demands of their job) following traumatic brain injury (TBI) and develop a work instability scale specific to this population. Method: Work instability (WI) following TBI was explored through qualitative interviews which were then used to generate items for a work instability scale (WIS). Rasch analysis was used to examine the scaling properties of the TBI-WIS which was then validated against a gold standard of expert vocational assessment by occupational psychologists. Results and conclusion: The resulting measure is a 36 item, self-administered scale which can be scored in three bands indicating low, medium and high risk of job retention problems. The scale meets modern psychometric requirements for measurement and presents an opportunity in routine clinical practice to take positive action to prevent job loss.

Living with thalidomide: Health status and quality of life at 40 years:

Thalidomide was first synthesized in 1953 and was subsequently marketed as a mild hypnotic and sedative in more than 20 countries. By 2001 it was estimated that there were 5000 survivors from the 10,000 – 12,000 babies who were, as a result, born with severe abnormalities. For these survivors, recent concerns have emerged about their physical state, in particular their levels of pain and their ability to maintain independence. It was therefore wished to ascertain health status and current concerns amongst a sample of survivors living in the UK. A combination of qualitative and quantitative methodologies was employed. Qualitative interviews were undertaken with a sample drawn from the population affected by thalidomide known to the Thalidomide Trust. Selection of participants was based upon a theoretical sample frame. Postal questionnaires to examine health status and various psychosocial aspects concerned with living with the consequences of thalidomide were sent subsequently to these same participants and to a random sample of those not originally drawn for the qualitative interviews. For the qualitative interviews, 28 agreed to take part; two refused and the remainder did not respond. Those agreeing to interview were representative of the original compensation bands (Chi-Square = 3.929; p = 0.416). Several themes emerged from these interviews, including the effects on work and career; coping in terms of attitude to life, self-image, confidence, self-esteem, stress and emotion; relationships, independent living issues and emergent problems such as pain, quality of life, and anxiety about the future. A postal questionnaire was then sent to those who had agreed to interview (28), plus a random sample of the remaining group who were not initially chosen for the qualitative interviews. In total 82 people were sent the questionnaire, of whom 41 (50%) responded. Two-thirds of responders were female. Seven out of ten lived with a partner, and over half (56%) had children. Almost half (46%) were in work, but 32% reported they were permanently unable to work because of disability. Current levels of impairment were found to be similar across groups defined by the original compensation band. In contrast, the activity limitation measures showed a steep gradient across bands but only 37% considered themselves disabled. Nevertheless, despite the restriction in activities for some, levels of participation were similar across bands; likewise simple summary items on health status and quality of life were similar and 70% reported their quality of life (QoL) was good or better than good. Yet nine in ten believed that their body was less flexible than in the past. Almost as many reported they were less able to carry things. It turns out that when compensation bands were grouped (1 – 3, 4 – 5) to highlight those most severely affected according to the original assessment, then those in the higher band grouping reported significantly more musculoskeletal problems, high levels of fatigue and increasing dependency and feelings of vulnerability. It is clear that the original ranking of disability severity, as expressed through the compensation, bands (allocated in early childhood in most cases), is consistent with current ranking of limitations in activity and participation. Nevertheless, despite high levels of disability amongst some survivors, lifelong adjustments to the original impairments have resulted in more than two thirds reporting at least a good quality of life. However, survivors expressed increasing concern about emerging musculoskeletal and other problems which may compromise hard-won independence.

Cryoprobe Treatment: An Alternative to Phenol Injections for Painful Neuromas After Amputation

AJR 2008; 191:W313 0361–803X/08/1916–W313

DVT and pulmonary embolism after acute infection.

At fi rst glance, this study by Liam Smeeth and colleagues (April 1, p 1075) was impressive, making use of a database comprising “more than 20 million person-years of observation from 220 general practices”. The method used was laid out in an earlier paper on adverse events from vaccines. The authors of that paper reported on both the relative incidence and attributable risk associated with the vaccine. We were surprised that Smeeth and colleagues chose to report only the incidence risk ratio, despite apparently having data on unexposed cases (used in adjustment for the eff ects of age) which would give access to attributable risk rates. Surely this was a missed opportunity. A doubling of relative risk might mislead the unwary reader into considering thromboprophylaxis after any lower respiratory tract or urinary tract infection. This would be appropriate if, for example, the risk doubles from 10 in 100 to 20 in 100, but would not make clinical sense if, for example, the risk increased from one in a million to two in a million. Perhaps the existing data set would allow this aspect to be investigated? We declare that we have no confl ict of interest.