Christine Rodriguez

Effects of high‐intensity endurance exercise training in the G93A mouse model of amyotrophic lateral sclerosis

The G93A transgenic mouse has a mutation in copper/zinc superoxide dismutase (CuZnSOD) that results in oxidative stress and motor neuron loss. Endurance exercise training is known to increase antioxidant capacity in skeletal muscle. Therefore, we hypothesized that endurance training may extend onset of disease or survival in the G93A mouse. We examined the effects of high‐intensity endurance exercise training (45 min/day, 5 times/week, progressive increase from 9 to 22 m/min) on disease onset and survival in G93A mice. Endurance training did not affect clinical onset, although it hastened death in male mice (P < 0.05). Endurance‐trained males had a statistically significant decrease in rotarod performance at 112 days (P < 0.05), whereas sedentary males decreased at 119 days (P < 0.05). Endurance‐trained and sedentary females decreased at 126 days and 129 days, respectively (P < 0.05). Female mice lived longer than males (P < 0.05), and there was a trend for hastened clinical onset in males (P = 0.062). We conclude that high‐intensity endurance exercise training does not affect onset of clinical symptoms in G93A mice but hastens a decrease in motor performance and death following onset of clinical symptoms in male mice only. In light of a recent report describing increased survival following low‐intensity endurance training, it appears that training intensity is an important determinant of survival in the G93A mouse.

Diagnostic utility of a modified forearm ischemic exercise test and technical issues relevant to exercise testing.

The sensitivity and specificity of a modified forearm ischemic test (FIT) are described in the diagnosis of glycogen storage disease, myoadenylate deaminase deficiency, and mitochondrial disease. FIT and muscle biopsy results were reviewed from 99 patients (glycogen storage disease [GSD], myoadenylate deaminase deficiency [AMPD], mitochondrial disease [MITO], miscellaneous neuromuscular disorders, and controls). The influence of catheter placement and an antecedent sugar bolus were also assessed in healthy young men. The FIT had a sensitivity of 1.00 and a specificity of 1.00 for a diagnosis of GSD, whereas the corresponding values were 1.00 and 0.37 for AMPD deficiency. A baseline lactate of >2.5 mmol/L provided the highest sensitivity (0.62) and specificity (1.00) for MITO disease. A baseline and +1 min sample provided optimal sensitivity and specificity for GSD and AMPD deficiency. Catheter placement in any vein other than the ipsilateral antecubital resulted in attenuated lactate responses (P < 0.0001). A pre‐FIT sugar bolus did not alter the postexercise lactate or ammonia response. Thus, a modified FIT was helpful in the diagnosis of GSD and excluding AMPD deficiency, but not in the diagnosis of MITO disease. Catheter placement is critical to the interpretation of a FIT, whereas pretesting diet is less important. Muscle Nerve 27: 359–366, 2003

The stress process in palliative cancer care: A qualitative study on informal caregiving and its implication for the delivery of care

Objective: The primary objective of this study was to examine how the comprehensive nature of the Stress Process Model could elucidate on the stressors associated with caring for a palliative cancer patient. Method: A qualitative research strategy involving home-based face-to-face interviews with 12 bereaved family caregivers was used to examine the caregiving experience. Results: The primary stressors associated with caring for the palliative cancer care patients stemmed from care recipient symptoms and personal care needs. The absence of adequate support from the formal health care delivery system was a consistent message from all participants. There was evidence of financial stress primarily associated with the purchase of private home care to supplement formal care. In contrast, the resources that family caregivers relied on to moderate the stressful effects of caregiving included extended family, friends, and neighbors. While the stress of direct caregiving was high, the study revealed that formal care was also a significant source of stress for family caregivers. Conclusion: It was concluded that an appropriately financed, integrated system of care that followed a person-centered philosophy of care would best meet the needs of the patient and his or her family.

Misclassification due to age grouping in measures of child development

Purpose Screens for developmental delay generally provide a set of norms for different age groups. Development varies continuously with age, however, and applying a single criterion for an age range will inevitably produce misclassifications. In this report, we estimate the resulting error rate for one example: the cognitive subscale of the Bayley Scales of Infant and Toddler Development (BSID-III). Design Data come from a general population sample of 594 children (305 male) aged 1 month to 42.5 months who received the BSID-III as part of a validation study. We used regression models to estimate the mean and variance of the cognitive subscale as a function of age. We then used these results to generate a dataset of one million simulated participants and compared their status before and after division into age groups. Finally, we applied broader age bands used in two other instruments and explored likely validity limitations when different instruments are compared. Results When BSID-III age groups are used, 15% of cases are missed and 15% of apparent cases are false positives. Wider age groups produced error rates from 27% to 46%. Comparison of different age groups suggests that sensitivity in validation studies would be limited, under certain assumptions, to 70% or less. Implications The use of age groups produces a large number of misclassifications. Although affected children will usually be close to the threshold, this may lead to misreferrals. Results may help to explain the poor measured agreement of development screens. Scoring methods that treat child age as continuous would improve instrument accuracy.

Psychometric properties of the DCD-Q-07 in children ages to 4–6

It is important to identify Developmental Coordination Disorder (DCD) early in a childs life to allow for proper and timely intervention and support, and to reduce the negative secondary consequences associated with this condition. In this study we assessed the psychometric properties (construct validity, concurrent validity, reliability and test accuracy) of the Developmental Coordination Disorder Questionnaire (DCD-Q-07) in preschool children. A community-based sample of children ages 4-6 (n=181) were screened for motor difficulties using the Movement Assessment Battery for Children (M-ABC-2). Use of the M-ABC-2 resulted in the identification of 29 children below the 15th percentile, which we classified as probable DCD. Parents of these children concurrently completed the DCD-Q-07 to report their childs motor performance. The DCD-Q-07 demonstrated high internal consistency for both the full scale (alpha=0.881) and each subscale: control during movement (alpha=0.813), fine motor and handwriting (alpha=0.869) and general coordination (alpha=0.728). Moderate correlations (r=0.47-0.63) were also seen between the subscales on the DCD-Q-07, the strongest correlation being between control during movement and general coordination (r=0.63). Based on published age and sex cut points, the DCD-Q-07 showed poor sensitivity (20.7%) but high specificity (92.1%) against the M-ABC-2. Overall agreement with the M-ABC-2 was low using ROC analysis (area under the curve=0.654). Although it is important to screen for DCD in young children, the DCD-Q-07 may not be the best choice as a screening tool for DCD in preschool children ages 4-6 due to its low test accuracy.

Psychological distress and parent reporting on child health: The case of developmental delay

BACKGROUND Caregiver-completed screening questionnaires are a common first step in the identification of developmental delay. A caregivers mood and anxiety level, however, may affect how he or she perceives and reports possible problems. AIMS In this article, we consider the association between caregiver distress and the accuracy of the Ages and Stages Questionnaire (ASQ), a widely-used screen. METHODS AND PROCEDURES Our sample includes 857 parent-child dyads drawn from the Psychometric Assessment of the NDDS Study (PANS) and the NDDS Alternate Responses Study (NARS). Parents completed the ASQ and the K6, a brief measure of generalized distress. Children were assessed using the Bayley Scales of Infant and Child Development (BSID). We divided children on BSID result and used logistic regression to examine how distress influenced the ASQs accuracy in each group. RESULTS Of our 857 children, 9% had at least one domain below -2 standard deviations on the BSID, and 17.3% had positive ASQ results. Caregiver distress predicted a positive ASQ substantially and significantly more strongly among BSID-positive children than among others. This translates into slightly reduced ASQ specificity but greatly improved sensitivity among caregivers with higher distress. CONCLUSIONS At low to moderate levels of distress, greater distress is associated with greater ASQ accuracy.