Pain Provocation and the Energy Cost of Walking: A Matched Comparison Study of Older Adults With and Without Chronic Low Back Pain With Radiculopathy.

BACKGROUND AND PURPOSE: Chronic low back pain with radiculopathy (CLBPR) is common among older adults and can lead to walking difficulty. Energy cost of walking strongly predicts changes in walking speed, which is predictive of mortality in older adults. The purposes of this study were to examine (1) the impact of pain provocation on the energy cost of walking and (2) the relationship between pain intensity and change in energy cost of walking. METHODS: Older adults (60-85 years) with (n = 20) and without (n = 20) CLBPR were matched on age, sex, and diabetes presence/absence. Energy cost of walking was measured with a portable metabolic gas analyzer, as participants walked for 20 minutes or less. Energy cost and pain measurements occurred during early and late stages of walking. Percent change in energy cost was calculated. Participants were grouped by their pain response during walking: increased pain (n = 13); consistent pain (n = 7); no pain, matched to individuals with increased pain (n = 13); and no pain, matched to individuals with consistent pain (n = 7). We examined the within-groups change in energy cost for all groups, as well as the relationship between late-stage pain intensity and percent change of energy cost for individuals whose pain increased. RESULTS AND DISCUSSION: Within the increased pain group, energy cost of walking significantly increased from early to late stages (median change = 0.003 mL/kg/m, P = .006), and late-stage pain intensity explained 41.2% (p = 0.040) of the variance in percent change. Since pain appears to be linked to energy cost, effective pain management with walking may be an important factor in preventing mobility decline. CONCLUSIONS: Among older adults with CLBPR, pain provocation drives increases in the energy cost of walking. Because high energy cost of walking is predictive of mobility decline, clinicians may focus on effective pain management strategies during walking, which may potentially decrease the risk of mobility decline.

Reliability of ultrasound imaging for the assessment of lumbar multifidi thickness in older adults with chronic low back pain.

BACKGROUND AND PURPOSE: Ultrasound imaging (USI) has been shown to be a reliable measure for direct assessment of the lumbar multifidi among younger adults. However, given age- and chronic low back pain (CLBP)-related spinal changes, similar studies are needed before clinical use of USI among older adults with CLBP. The goals of this study were to evaluate intra- and interexaminer reliability for USI assessment of multifidi thickness at rest and during a contraction and to determine standard error of measurement values (SEMs) and minimal detectable change values (MDCs) among older adults with CLBP. METHODS: Thirty-one adults, aged 60 to 85 years, with CLBP were recruited. Two examiners performed USI assessments of multifidus thickness at rest and during a contralateral lower extremity lift. Intraclass correlation coefficients (ICCs) were used to estimate inter- and intraexaminer reliability. Additionally, SEMs and MDCs were calculated. RESULTS: All USI measurement techniques demonstrated excellent within-day, interexaminer procedural reliability (ICCs: 0.82-0.85) and good-to-excellent between-day, interexaminer procedural reliability (ICCs: 0.72-0.79). The SEMs ranged from 0.36 to 0.46 cm; MDCs ranged from 1.01 to 1.26 cm. Regardless of the measurement technique, examiner 1, the more experienced examiner, demonstrated lower SEMs and MDCs than examiner 2. DISCUSSION: Lower ICCs, greater SEMs, and greater MDCs for USI multifidus thickness assessment in older adults with CLBP, when compared with previously published, procedural reliability results for younger adults with and without low back pain, may indicate that imaging is more challenging in this patient population. Factors, such as examiner training and participant anthropometrics, may impact reliability. CONCLUSIONS: Good-to-excellent intra- and interexaminer USI procedural reliability may provide clinicians a direct assessment technique for clinical evaluation of the lumbar multifidi in older adults with CLBP. SEMs and MDCs may allow for accurate interpretation of USI assessments in this population.

Ultrasound imaging: intraexaminer and interexaminer reliability for multifidus muscle thickness assessment in adults aged 60 to 85 years versus younger adults.

STUDY DESIGN: Intraexaminer and interexaminer, within- and between-day reliability study. OBJECTIVES: To compare the intraexaminer and interexaminer procedural reliability of ultrasound imaging (USI) thickness measurements of the lumbar multifidus muscle at rest and during a contralateral lower-limb lift (CLL) between older (60-85 years of age) and younger (18-40 years of age) adults. BACKGROUND: Among younger adults, USI has been shown to be reliable and valid for assessing multifidus thickness. Older adults present with age-related changes that may impact assessment. To our knowledge, no USI studies have focused on establishing reliability for multifidus thickness assessments in older adults. METHODS: Two examiners performed assessments of lumbar multifidus thickness at rest and during a CLL in 30 older and 31 younger adults. Intraclass correlation coefficient (ICC) with 95% confidence interval, standard error of measurement, 95% minimal detectable change for resting and during the CLL, and percent thickness change were calculated. RESULTS: Within-day interexaminer procedural reliability for multifidus thickness measurements was similar among younger (ICC = 0.90-0.92) and older adults (ICC = 0.86-0.90), as was between-day intraexaminer and interexaminer reliability (younger adults, ICC = 0.84-0.94; older adults, ICC = 0.86-0.93). Throughout, estimates of percent thickness change were inconsistent (ICC = 0.31-0.86), and standard errors of measurement and minimal detectable changes were larger for older adults. CONCLUSION: Ultrasound imaging reliability for measurements of multifidus thickness at rest and during a CLL among older adults is consistent with previously published findings for younger adults. Among older adults, it may be preferable to have a single examiner conduct USI assessments.