Compromised encoding of proprioceptively determined joint angles in older adults: the role of working memory and attentional load.

Perceiving the positions and movements of one's body segments (i.e., proprioception) is critical for movement control. However, this ability declines with older age as has been demonstrated by joint angle matching paradigms in the absence of vision. The aim of the present study was to explore the extent to which reduced working memory and attentional load influence older adult proprioceptive matching performance. Older adults with relatively HIGH versus LOW working memory ability as determined by backward digit span and healthy younger adults, performed memory-based elbow position matching with and without attentional load (i.e., counting by 3 s) during target position encoding. Even without attentional load, older adults with LOW digit spans (i.e., 4 digits or less) had larger matching errors than younger adults. Further, LOW older adults made significantly greater errors when attentional loads were present during proprioceptive target encoding as compared to both younger and older adults with HIGH digit span scores (i.e., 5 digits or greater). These results extend previous position matching results that suggested greater errors in older adults were due to degraded input signals from peripheral mechanoreceptors. Specifically, the present work highlights the role cognitive factors play in the assessment of older adult proprioceptive acuity using memory-based matching paradigms. Older adults with LOW working memory appear prone to compromised proprioceptive encoding, especially when secondary cognitive tasks must be concurrently executed. This may ultimately result in poorer performance on various activities of daily living.

Neonatal baclofen withdrawal following intrauterine exposure.

BACKGROUND: Pregnant women with spinal cord injuries are often advised to continue oral baclofen during pregnancy to manage spasticity, though the potential for adverse events in neonates is not well understood. OBJECTIVE: Here, a case is described in which a male neonate with intrauterine baclofen exposure, born at 34 3/7 weeks via Cesarean section, demonstrated a two-minute episode of extensor posturing at fifteen minutes of life possibly concerning for baclofen withdrawal. His mother had taken baclofen 30 milligrams orally four times per day throughout pregnancy for management of spasticity associated with a remote cervical spinal cord injury. Due to concern for possible withdrawal, the neonate was started on a baclofen taper beginning within hours of birth while evaluation for alterative etiologies was underway. Symptoms were monitored using the Finnegan Neonatal Abstinence Scale. The neonate tolerated the baclofen taper well and was successfully tapered off by the fourteenth day of life with full resolution of symptoms and no apparent neurologic deficits. CONCLUSION: Further research is needed to assess the incidence of neonatal baclofen withdrawal with regard to maternal dosage and route of administration, and to determine the most appropriate monitoring and management protocols for the neonate.