Abstract: Background: 
Toe walking is a possible finding in individuals with ASD. In a previous study, we documented the presence of this behavior also during the maintenance of standing position from which the term “tip-toe behavior” (TTB). In a further study, using the Short Sensory Pro le (SSP) tool we found different patterns of sensory pro le in TTB ASD individuals with two opposite forms: “Under responsive/Seeks sensation” or “tactile hypersensitivity” Since in a pilot study we found a TTB decreasing during standing on a mattress when compared on a hard surface, we have developed a device to be worn within shoes consisting in a special insole for subjects with tactile hypersensitivity. 

Objectives: 
The study aim is to offer a proof of concept behind a rational approach to TTB treatment based on individual sensory profile. 

Methods: 
The ASD diagnosis followed the DSM-5 criteria, and a diagnosis confirmation was performed using ADOS-2. Two subjects (subject A: male, 15 years; subject B: male, age: 10,5 years) were selected among a sample of 14 TTB ASD subjects to whom the SSP tool was administered. Subject A expressing a “de nite difference” in “Under responsive/seeks sensation” section and a typical performance in “Tactile Sensitivity” section, while subject B expressing a “de nite difference” in “Tactile Sensitivity” section and a typical performance in “Under responsive/seeks sensation” section. We developed an insole made of soft material such as cellular rubber to be inserted inside each shoe. This insole has a constant thickness between 2.0 and 12.0 millimeters which is adapted to individual needs and a density between 0.10 and 0.20 g/cm³. 
Both subjects wore the device for 48 weeks, 6 hours a day,  ve days a week. At baseline (T0) and every four months (T1, T2, T3) TTB intensity during standing position was assessed using video recordings taken during a static task (playing in front of a playing table for 90 seconds) without shoes and with socks, using a standardized methodology previously described. The test was repeated in three different days. An independent therapist not involved in test operation analyzed the videos of the static task trials by calculating the cumulative time in seconds spent along ninety seconds on full feet support versus one foot on toes versus both feet on toes. The mean time of the three trials was then calculated for the three conditions. In this study, we considered as outcome measure the mean percentage of cumulative time spent with a foot on the tips plus both feet on the tips. 

Results: 
In subject A no changes in TTB intensity was found (T0 value = 71%; T1-T3 average value = 79%), while in subject B a marked reduction in TTB intensity was found (T0 value = 72%; T1-T3 average value = 36,3%). 

Conclusions: 
The results obtained in these case reports constitute a proof of concept for the development of special devices to treat TTB according to sensory pro le expressed. In particular in presence of “tactile hypersensitivity”, an intervention with special rubber insole seems rationale.

Notes: 

1 - University of Milano-Bicocca, School of Medicine and Surgery
2 - Villa Santa Maria Foundation