Milestones/Millstones
Kay A. Ferrell, Ph.D.
National Center on Low-Incidence Disabilities
Milestone
- A stone serving as a milepost;
- A significant point in development
Merriam-Webster
10th Collegiate Dictionary (2004)
Millstone
- Either of two circular stones used for grinding;
- Something that grinds or crushes
Merriam-Webster
10th Collegiate Dictionary (2004)
Milestones = Millstones?
Sometimes
Berthold Lowenfeld, Nancy Akeson
- "He mentored many of the current leaders in the field today."
- So did she.
- They both took me in:
- Shaped me with their ideas,
- Inspired me with their commitment,
- Challenged me with their questions.
Thanks
- Always wanted to be invited here,
- Always wanted to "pay back."
- Thank you for the privilege.
Only when . . .
Only when . . . educators stop applying to blind children the patterns devised for seeing children - only then can the blind child live up to his real potentialities.
Lowenfeld (1946)
Studies of blind children ...
Studies of blind children and their development indicate that the sequence of development is, in general, unchanged by blindness, while the appearance of the various developmental stages varies a great deal from individual to individual.
Lowenfeld (1956)
History of Developmental Assessment of Children with VI
- Norris, Spaulding, & Brody (1957)
N = 66
- Maxfield & Buchholz (1957)
N = 398
- Fraiberg (1977)
N = 10
Conclusions from Early Studies
- Children with VI generally acquire skills at the same time as typical children
- Any delays are the result of lack of exposure
Blind children ...
Blind children can learn to walk just as soon as seeing ones, only they have to be led around in the beginning more frequently than the others.
Kleig (1836)
There is little hard evidence...
There is little hard evidence that the rate and sequence of development of visually handicapped infants are any different from those of sighted infants.
Ferrell (1986)
Did Not Seem to Fit with the Children We Knew
New York City, 1986
Visually Impaired Infants Research Consortium (VIIRC)
- Began as conference proposal
- Group organized after submission!
- Consortium of New York City service providers and 1 university faculty
- No money/all volunteer
- No agreement on assessment battery
Identified 21 milestones
- Identified 21 milestones
- Individual biases/concerns
- Existing records or parent information
- Published when n = 81
- Ferrell, Trief, Deitz, Bonner, Cruz, Ford, & Stratton (1991)
- Nationwide contributions
Notes:
This table compares early developmental studies with VIIRC results. Participants in the VIIRC study were sitting before searching for a removed object, suggesting that the order of milestone acquisition was different. Fraiberg had found similar evidence.
Notes:
In this continuation of the previous table, which examines milestones typically achieved after 1 year, the difference in sequence is again suggested for the VIIRC participants. Language milestones (uses 2-word utterances) and gross motor milestones (walks down stairs alternating feet) seem to be achieved earlier than would be expected, if compared to typical development.
What if:
- Increase sample size
- Increase reliability
- Increase rigor
- Increase confidence in results
Project PRISM
A National Collaborative Study on the Early Development of Children with Visual Impairments
Hopes
- Find "truth"
- Demonstrate the impact of blindness on development
- Prove:
- Young children with visual impairments develop differently
- Specialized programs superior
- Specialized teachers superior
Do children with visual impairment attain developmental milestones at chronological ages that differ from sighted children?
Seems so . . .
- 12 milestones delayed
- 5 milestones within the range of typical acquisition
- 2 milestones acquired early
- 6 milestones acquired in a different sequence than typical development
(All participants, N = 14 to 126 for individual milestones)
VI Only vs. Additional Disability
No significant difference for:
- Reaches for and touches objects
- Transfers objects from hand to hand
- Uses pronouns
- Controls bowels
VI Only vs. Additional Disability, continued
Significantly later acquisition by children with additional disability for:
- Searches for removed object
- Sits alone without support
- Feeds self
- C + V words
- Crawling
- Plays interactive game
VI Only vs. Additional Disability, continued
- Points to body part
- Removes garment
- Follows directions
- 2-word sentences
- Repeats 2 digit sequence
Do children with visual impairment attain developmental milestones at chronological ages that differ from sighted children?
- Children with additional disabilities generally acquired milestones later
- Age of acquisition was significantly later for children with additional impairments for 12 of 19 milestones
- Children without additional disabilities acquired some milestones (6) sooner, or within the range (4) of typical children
Children without Additional Disabilities
Within range
- C + V sounds
- Points to body part
- Uses pronouns
- Walks down stairs alternating feet
Earlier:
- Plays interactive game
- Removes garment
- Follows directions
- Controls bowels
- Repeats 2-digit sequence
- Relates past experiences
Do children with visual impairments attain developmental skills in a different sequence than sighted children?
Milestones,by Disability Risk
Notes:
This bar chart arranges the milestone results for children without additional disability, those with mild additional disability, and those with severe additional disability, from left to right in the order in which the milestones are acquired by typically developing children. The milestones are plotted along the x-axis; the month of acquisition, along the Y-axis. The expectation is that the height of the bars would increase (indicating later ages) as the milestones progress from left to right. For each group of children (none, mild additional disability, and severe additional disability), the height of the bars goes up and down. This fluctuation indicates that some skills are acquired in a different sequence. Furthermore, the pattern is different for each group
Milestones that Differed Significantly by Disability Risk
Notes:
If the analysis is reduced to two groups (those with and those without additional disability), tests of significance indicate that 12 milestones differed significantly. Again, the bar chart arranges the milestones from left to right in the order in which the milestones are acquired by typically developing children. The milestones are plotted along the x-axis; the month of acquisition, along the Y-axis. While there is still the fluctuation in sequence for both groups, it is generally the same sequence for both groups. Children with additional disabilities generally acquired 12 milestones at a later age.
Are there differences in the rate and sequence of development among children with different visual disorders?
Not as much as we had thought:
For 10 milestones, children with ROP acquired skills later than other children with visual impairments
Milestones that Differed Significantly by Visual Disorder
Notes:
This bar chart presents the milestone results for children with the four most common visual disorders: optic nerve hypoplasia, albinism, retinopathy of prematurity, and cortical visual impairment. The milestones again are arranged from left to right in the order in which the milestones are acquired by typically developing children. The milestones are plotted along the x-axis; the month of acquisition, along the Y-axis. The expectation is still that the height of the bars would increase (indicating later ages) as the milestones progress from left to right. For each visual disorder, the height of the bars fluctuates, suggesting a different sequence of milestone acquisition for each group.
Are there differences in the rate and sequence of development among children with varying levels of visual function?
Again, not what we would predict:
- Only one milestone demonstrated a significant difference among visual function levels:
- Plays interactively with adults.
- Children with NLP acquired later
- Differences not significant for any other milestone
Milestones acquired in different order by visual function level,
- Milestones acquired in different order by visual function level,
- But not statistically significant
- No pattern is apparent
Milestones, by Visual Function
Notes:
This bar chart arranges the milestone results for children with different levels of visual function - no light perception, light perception, severe low vision, and moderate low vision - from left to right in the order in which the milestones are acquired by typically developing children. The milestones are plotted along the x-axis; the month of acquisition, along the Y-axis. The expectation is that the height of the bars would increase (indicating later ages) as the milestones progress from left to right. Again, the fluctuation in the height of the bars is evident for each group. What is surprising is that the group with the least amount of vision does not always acquire milestones at a later age, or that the group with the best vision does not always acquire milestones at an earlier age.
Are there differences in the rate and sequence of development among children who differ along various social, cultural, or other variables?
Also not what we had expected:
- No differences in development apparent based on income, ethnicity, parent age, parent education, or other socio-cultural variables.
- Age of acquisition for 13 milestones was significantly different for children whose gestation was full-term.
- Acquired milestones earlier.
Milestones that Differed Significantly by Gestational Age
Notes:
This bar chart arranges the milestone results for children born preterm and at term, from left to right in the order in which the milestones are acquired by typically developing children. The milestones are plotted along the x-axis; the month of acquisition, along the Y-axis. The expectation is that the height of the bars would increase (indicating later ages) as the milestones progress from left to right. The bars again demonstrate a fluctuation in sequence of milestone acquisition, although the fluctuation is not as great for children born at term. Children born preterm generally acquired the skills at a later age.
The primary question is not what you know
but how you know it.
Aristotle
Milestones that were NOT Significantly Different
For disability risk:
- Reaches for and touches objects
- Transfers objects from hand to hand
- Uses pronouns
- Controls bowels
For gestational age:
For gestational age:
- Transfers object from hand to hand
- Walks without support
- Controls bowel movements regularly
- Walks down stairs alternating feet
- Copies circle
- Relates past experiences
Milestones that Differed Significantly by Visual Function
- Plays interactive games with adult
- Children with NLP acquired behavior significantly later than all other children.
- Also impacted by additional disability and prematurity
- Possible interaction effect
It is denying the facts to hold, as a great many of our educators of the blind do, that the blind child’s organization and growth can continue as in the normal child except for the absent sense.
Cutsforth (1951)
The growth and development of the blind child is more LIKE than UNLIKE that of the sighted child. In each area his growth and development passes through the same sequence, but his rate may be slower due to direct and indirect influences of his visual impairment.
Scholl (1973)
The danger lies in the easy conclusion that developmental norms for the sighted population should be set as goals for the visually impaired population.
Warren (1984)
Stepping Stone
- A stone on which to step (as in crossing a stream)
- A means of progress or advancement
Merriam-Webster
10th Collegiate Dictionary (2004)
Typical Development for Children with Visual Impairments
Notes:
This bar chart compares the age equivalent scores of children diagnosed as visually impaired and without additional disabilities on the Battelle Developmental Inventory (Newborg et al., 1984) to their chronological age at the time of testing. Children were tested at age intervals of 0-5 months, 6-11 months, 12-17 months, 18-23 months, 24-35 months, 36-27 months, and 48-59 months. The chart indicates that age equivalent scores of children without additional disabilities were very close to chronological age, ranging from about a month’s difference at 0-5 months, to 5 months’ difference at 48-59 months.
