The development of symmetrical OKN in infants: quantification based on OKN acuity for nasalward versus temporalward motion.

We quantified OKN asymmetry in 140 normal infants, 3-24 months old, by varying spatial frequency to determine OKN acuity for temporal-to-nasal (T-N) versus nasal-to-temporal (N-T) motion. At all ages, OKN acuity was asymmetrical (better for T-N than for N-T motion) but the size of the asymmetry decreased from 3.2 to 0.7 octaves between 3-24 months, primarily because of improvements in OKN acuity for N-T motion. The results suggest that immaturities in the cortical pathways involved in OKN persist until at least 2 years of age.

Assessment of health status and health-related quality of life in survivors of Hodgkin's disease in childhood.

Although the great majority of children with Hodgkin's disease survive with modern treatment strategies, the list of late sequelae is long, yet there is no published information on the comprehensive health status and health-related quality of life (HRQL) in this population. In the experience of a single institution, survivors of Hodgkin's disease in childhood were invited to self-report on their health status using a 15-item questionnaire connected to the Health Utilities Index, a series of multi-attribute health status classification systems that, in turn, are linked to preference functions which provide single-attribute and global utility scores for HRQL. The mean global utility score was 0.85 (on a 0 = dead to 1. 0 = perfect health scale), a figure less than that in survivors of acute lymphoblastic leukemia (ALL) but comparable to that in survivors of brain tumors (0.84) or extremely low birthweight (ELBW 0.82). The burden of morbidity is emphasized by the ratio of the numbers of health states per patient:0.67 for survivors of Hodgkin's disease, 0.66 for survivors of brain tumors, 0.39 for survivors of ELBW, 0.47 for survivors of high-risk ALL and 0.28 for survivors of standard-risk ALL. In Hodgkin's disease survivors, the attributes affected most commonly and severely were pain, cognition and emotion. This experience demands exploration of the health status and HRQL in a much larger cohort of such survivors, perhaps in the context of co-operative group studies.

An evaluation of the length-tension relationship in elderly human ankle dorsiflexors.

Aging is thought to be associated with a decreased elasticity of skeletal muscle, which may be predicted to affect the optimal length at which peak tension is developed. This was assessed in the present study, in which we examined the effect of aging on the muscle length-tension relationship in the right ankle dorsiflexors of 60 subjects aged 20-40 years (M = 25.3; 15 males, 15 females) and 60-80 years (M = 68.8; 15 males, 15 females). Evoked contractile properties, 1-sec tetanic contractions (at 20, 50, and 80 Hz), and maximal voluntary contractions (MVC) were measured at 10 joint angles (15 degrees dorsiflexion to 30 degrees plantarflexion, in 5 degrees increments). Peak twitch torque occurred at the extreme of plantarflexion (30 degrees P) in both elderly and young adults, and although males had significantly greater twitch torques than females, there was no difference between the elderly and young adults. Maximum tetanic torque and MVC torque occurred at 30 degrees P and 20 degrees P, respectively, but in this case the young adults were significantly stronger than the elderly adults, and the males stronger than the females at all joint angles. There was no difference in the torque-angle relationship between elderly and young adults in any of the evoked or voluntary measures. At each of the three frequencies, the rise time of tetanic torque was also similar between elderly and young adults. These results suggest that any age-related change in the elastic properties of the ankle dorsiflexors does not affect the length (as inferred by joint angle)-tension relationship in this muscle group.