Monday, August 27, 2012

Idiopathic toe walking: Insights on intervention


Idiopathic toe walking: Insights on intervention


As researchers explore the possibility that idiopathic toe walking has an underlying neurologic cause, clinicians continue to refine treatment strategies to keep ITW patients off their toes. Orthotic devices play a key role, with lower-profile devices growing in popularity.
By Emily Delzell
New research suggests that idiopathic toe walking, long considered a gait pattern that occurs in the absence of other abnormalities, may have an underlying neurological cause. Investigators need to under­take much more research to confirm this early hypothesis, but, until more is known, researchers suggest that clinicians be alert for subtle signs of other sensory and motor skills issues in children with the diagnosis.
It’s normal for toddlers to walk on their toes as their gait devel­ops, but when this pattern persists in children older than two years, it’s a cause for concern. Toe walking can be the first sign of neuro­log­ical or developmental condition such as cerebral palsy or autism spectrum disorder.1 In addition, bilateral toe walking is often seen in children with congenital muscular dystrophy and global de­velopmental delay. (Unilateral toe walking is typically the result of trauma.)2
“Ultimately, the diagnosis is given when there is no medical reason for toe walking,” said Cylie Williams, PhD, a podiatrist with Southern Health, Cardinia Casey Community Health Service, Cran­bourne, Australia.
Williams and her colleagues have developed the Toe Walking Tool, a validated 25-item questionnaire that can help practitioners identify otherwise healthy children who toe walk as well as reveal risk factors for other medical conditions that may require further evaluation from a specialist.2
Although Williams’ tool is used to rule out these well-charac­terized conditions, her recent work has lead her to suspect the gait pattern may not be truly idiopathic, but instead, “the result of some very mild neurological changes we still don’t understand.”
Williams noted that several studies3-5 have described increased sensitivity to vibration and hypersensitivity in the hands or feet in children and adults with Asperger syndrome and autism spectrum disorder and that gait changes, including toe walking in children, are linked to these disorders.6
In 2010 Williams and her colleagues completed a literature review on the relationship between toe walking and sensory processing dysfunction.7 They found only a handful of studies that discussed a potential link between ITW and sensory processing issues, but noted that clinical observations and anecdotal reports of the possibility of such a connection were becoming more common.7
To test whether children diagnosed as idiopathic toe walkers might also demonstrate changes in sensory processing, Williams and her colleagues recruited 30 healthy children aged 4 to 8 years who were not toe walkers (NTW) and 30 children in the same age range who the researchers identified as current idiopathic toe walkers using the exclusionary toe-walking tool.
They measured the children’s vibration perception threshold (VPT) in the right hallux using a vibratory sensory analyzer that delivers a frequency vibration of 100 Hz (amplitude range, 0-130 µm) through a Teflon-coated pin mounted in a footplate (Figure 1). The vibration mimics the everyday tactile input that allows the brain to sense fine surface texture changes, which, in the feet, play a key role in protection and proprioception.8
The results, e-published in March by the Journal of Child Neuro­logy, showed that the children in the toe-walking group had a significantly lower VPT than those in the NTW group (mean, 1 µm vs 1.8 µm; P = .001).
Figure 1. Foot in position for vibration perception analysis by Williams et al. (Image courtesy of Cylie Williams, PhD.)
“The vibration study paper highlighted a difference in tactile sensory perception, or heightened feelings of touch, that the children with ITW had, indicating that these children were perhaps more sensitive in some way to touch,” Williams said. “We tested this as part of a larger study of the motor skills and sensory processing abilities of children who have an ITW gait. The rest of the results are being finalized for publication, but we found that children who had an ITW gait had problems with some specific gross motor skills and displayed some unusual behavioral changes as a result of different sensory input. This result indicated there might be some immaturity or difference in the way the children who have an ITW gait process sensory input.”
During data collection for the larger study the Australian researchers turned up an unexpected finding that also hinted at some neurological basis for ITW.9 They recorded the preferred hand of each child in the ITW and NTW groups and found that only 10% of the children in the NTW cohort preferred their left hand, a result that is in line with population norms.9 In contrast, 33% of the children in the toe-walking group preferred their left hand.9 Previous research has linked left handedness to difficulty with spatial tasks and dyslexia.10-12
“The left-handedness result also feeds into this [the theory that children with ITW may have a mild neurological condition], and, while the children may be genetically left handed, there is also the possibility that the left handedness is neurologically based,” Williams said. “This result again points to the ITW gait being the result of some mild neurological impairment. The study on this cohort of children who appeared to be neurologically normal but toe walked found that there were all these interesting little signs that, in fact, the toe walking may actually be the result of some very mild neurological changes—but we’re still not sure what these might involve.”

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