Age

Atypical Behavior

4 to 5 months

Unable to extend arms fully and toward midline in supine; unable to sit erect

6 to 7 months

Inability to sit erect without support; inability to achieve midline hand position in supine or sitting; no evidence of lateral or forward propulsion

8 to 9 months

No transition from commando crawl or bunny-hop to reciprocal locomotion; W-sit only or preferred sitting position

1 year

Inappropriate trunk and extremity stiffness or laxity: instability; poor coordination may prevent hands-knees locomotion and emergence of standing

13 to 14 months

Absence of transition from bottom scooting, bunny hopping, or sequential rolling to more mature forms of locomotion

15 to 16 months

If onset of walking has not occurred, screen for delays in other areas to determine if need exists for in-depth assessment

17 to 18 months

18 months ceiling age for onset of walking independently; if not present, refer for comprehensive evaluation for developmental delay

2 years

Insecure balance leading to many falls

30 months

Tentative in most/all gross motor activities; difficulty determining body placement for mounting ride-on toys

3 years

Unable to mount, dismount or sustain any rotary motion on the pedals of a riding toy; base of support may remain abnormally wide or narrow, indicative of ongoing balance or tonal responsivity problems

42 months

Response times insufficient to succeed at catching a ball; kicking, hopping, standing on one leg not emerging

4 years

Skills requiring moderate to maximal balance challenges such as climbing and jumping off heights not attempted; catching, kicking balls difficult; hand preference ambiguous

 5 years

Difficulty mounting or pedaling any ride-on toy; difficulty imitating a motor act after seeing another child complete it