Grip force parameters in precision grip of individuals with myelomeningocele

The aim of this study was to characterize impairments of hand function in individuals with myelomeningocele (MMC) using a quantitative method. A grip-lift task was studied in 29 individuals with MMC (17 females, 12 males; mean age 12 years 4 months, SD 5 years 6 months; range 4 to 28 years) and 29 age- and sex-matched control participants. A small object (weight 200g) was grasped and lifted with a precision grip of the dominant hand and grip forces (GF) and time intervals were measured. Sensibility was examined with a two-point discrimination test. In those with MMC, the latency between GF onset of the thumb and index finger and ensuing preload duration were both significantly prolonged (p<0.01). Fingertip forces were excessively high and variable. Several parameters differed significantly between those with MMC and control individuals: GF peak, GF at start of loading, mean GF, and the onsets of the GF during static holding. Although the two-point discrimination task indicated deficits of sensibility, these did not correlate with grip force parameters. Results demonstrate that fine motor skills in patients with MMC are impeded by slowness and inadequate adjustments of manipulative forces.