Tip-Toe Behavior (TTB) Presentation Pattern and Achilles's Tendon Shortening: Are They Related in ASD Children?

Background:  

About twenty percent of individuals with ASD walk on their tiptoes. Persistent toe-walking in children with ASD may contribute to secondary motor deformities by producing a shortening of the Achilles’s tendon (made up by the soleus muscle SM and gastrocnemius muscle GM). It is not clearly understood why some ASD subjects develop this tendon shortening while others do not. A possible contributing factor could be the amount of time children spend in TTB during the day, i.e. if TTB is present only in running (class 3) or in walking and running (class 2) or in standing, walking and running (class1), three mutually exclusive patterns we described in a previous study.

Objectives:  

The aim of this cross-sectional study is to evaluate the relationship between the three TTB presentation patterns described above and the Achilles’s tendon shortening.

Methods:  

The study includes 69 consecutive children (57 males, 12 females, mean age = 14 years – 3.6 SD) diagnosed with ASD according to the DSM V criteria and under observation at our institute. The severity of ASD was established through ADOS (2nd version). A therapist assessed the presence of Tiptoe behavior (TTB) during standing, walking and running using direct observation and an interview of the main caregiver living with the children. Another therapist assessed both the soleus and gastrocnemius muscles length using a manual goniometer.  

Results:  

Overall 23/69 children presented TTB. Ten children exhibited it in standing, walking and running (class 1), 8 only during walking and running (class 2) and 5 children only during running (class 3).

There were no significant differences in the mean overall ADOS score of the TTB children according to  TTB classes: 20.13 (5.48 SD) no TTB class;  23.90 (5.36 SD) class1, vs 21.13 (4.29 SD) class 2 and vs 23.60 (5.13 SD) class3.

The mean length of the left GM of non TTB children was 9.20° (5.18°SD) vs a value of -0.2°(10.16°SD) TTB class 1( p<0.01), vs 6° (2.73°SD) TTB class 2 (p NS) , vs 10.2° (9.92°SD) TTB class 3 ( p NS). The mean length of the right GM of non TTB children was 9.02° (5.39°SD) vs a value of 1.7°(10.91°SD) TTB class 1(p<0.01), vs 8.75° (4.58°SD) TTB class 2 ( p NS), vs 11.6° (4.39°SD) TTB class 3( p NS). The mean length of the left SM of non TTB children was 21.07° (7.67°SD) vs a value of 10° (9.65°SD) TTB class 1 ( p< 0.05), vs 18.63° (9.90°SD) TTB class 2( p NS), vs 22.80° (6.30°SD) TTB class 3( p NS). The mean length of the right SM of non TTB children was 19.33° (6.87°SD) vs a value of 9.7°(8.84°SD) TTB class 1( p <0.05), vs 19.25° (8.26°SD) TTB class 2( p NS), vs 21.8° (6.61°SD) TTB class 3 ( p NS).

Conclusions:  

The data confirm the existence of a positive relationship between the presence and severity of TTB and the Achilles’s tendon shortening, with a significant difference between the NonTTB group and  Class 1 TTB group.