In this group of children, the mean DQs were less than the standard score of 100. The mean of each group indicated delayed developmental quotients (DQs <70) for gross motor skills at the initial evaluation. The minimal impairment group had initial fine motor, cognitive and receptive language skills DQs above the level of delayed (>70) and statistically higher than the global impairment group. These results suggest that developmental quotients determined at initial evaluations, especially fine motor, cognitive and receptive language skills may be helpful in determining outcomes of children that present with hypotonia as infants. These results should be taken cautiously since not all the subjects underwent developmental testing. Further research on the relationship between initial DQs and outcomes on a larger sample size would be beneficial, as would research correlating specific ranges of DQs with certain outcomes.
The reported age when walking well was observed in both the minimal and globally impaired group was to be about 22 months and 30 months, respectively. Walton had similar findings, as he reported a delay in the attainment of motor milestones in the BCH population.2 This result should be taken only generally since it was derived from the survey question “At what age did your child walk well on his own?” The question did not specify any criteria for “walking well on own” and thus may have been open to some interpretation.
The manifestations of impaired motor functioning were also detected in this study. Almost 59% of the minimal impairment group was reported to have poor coordination and 35% were reported to display clumsy walking. These results varied slightly from the study done by Shuper et al., who found half of a similar group of subjects to have clumsy gait.11 In the older minimal impairment group, 58% were reported as having poor handwriting, 70% had difficulties in math, 58% were inattentive, and 53% were distractible. All of these outcomes occurred more frequently in the minimal impairment group as compared to the transient group. Some in the minimal impairment group were diagnosed with a learning disability (44%). However, a greater frequency of parents was concerned about specific related learning issues, perhaps indicating under diagnosis of learning disability in the group with idiopathic hypotonia. These results are also consistent with what therapists have indicated as characteristics of hypotonia.13
Speech therapy, physical therapy, and occupational therapy were highly used in the minimal impairment group, with almost 83% of the transient and minimal impairment subjects receiving physical therapy and approximately 91% receiving speech therapy. The utilization of speech therapy beyond two years was still high (90.7%). This statistic supports the results of Shuper, who found half of the subjects with BCH to display speech delay.11 In this study, data were not collected to clearly determine the exact age at which these services were begun, but research in this area is recommended to determine if there is a delay in the commencement of needed services in the minimally impaired population of patients born with idiopathic hypotonia as compared to when services are begun in the more globally impaired diagnoses.
The last area we addressed was familial incidence of idiopathic hypotonia. Parush found in his report a high familial incidence of BCH.3 In this study, we noted that the presence of learning disability, ADHD, motor deficit, and neurological deficit in the family history, were each more frequently found in the minimal and transient groups combined as compared to the global group, though the overall frequency was small.
A limitation of this study was the relatively low response rate and overall number of subjects. Though 10.5% of the infants diagnosed with hypotonia had little to no residual problems (the transient group) and 32.4% had minimal impairments, it is difficult to say if this percentage is reflective of the population of children that are diagnosed with hypotonia. Also with this response rate it is difficult to say if those parents that did respond are representative of the population. Parents more affected by the hypotonia of their child may have been more inclined to respond. Despite these limitations, the relative percentages of the outcomes within a group were similar to what the previous researchers have found. Another limitation of the study was the questionnaire used was not validated. Because wide variations occur in even normal development, the data should be considered only as a general and potential trend in this group of children.
The overall aim of this study was to better understand the outcomes related to infant-diagnosed idiopathic hypotonia. We found that children diagnosed with idiopathic hypotonia in infancy typically had developmental scores below the standard score of 100 but were considered delayed initially (DQ <70) in only gross motor and expressive language skills. All the developmental scores were lower in those with global impairments. With regard to outcomes later in life, these children walked later than normal; heavily utilized rehabilitation services; and often demonstrated learning, language and motor deficits later in life.
The findings in this study may inform pediatric therapists of the expected outcomes for children with hypotonia and may assist therapists in developing further outcome and interventional research in this area. These findings may also assist parents, teachers, therapists and other resource providers to better anticipate a child’s needs and allow for more informed decisions when considering the need for services.
Further research is warranted to look more closely at the specifics regarding resources utilized by this group such as age at initiation of services, span of services, and frequency of services. More research is also needed in the area of idiopathic hypotonia and learning disability later in life, as well as familial incidence of idiopathic hypotonia. Further research is also warranted on the relationship of developmental quotients to serve as tools in determining a functional prognosis for these children. A larger sample size is recommended for future studies. The findings of this study should be taken cautiously. This was a retrospective study based on incomplete medical records. These findings need to be confirmed by a prospective study from the time of initial diagnosis to later years using established measurement instruments and follow-up methodology.
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The following is a questionnaire that asks questions about your child, his or her current function, what services they may have received. Please answer the questions to the best of your ability. The questionnaire should only take 5–10 minutes. If you have questions about any of the items, please call XXXX at XXXX. Your participation is appreciated and your contribution will greatly assist us in understanding hypotonia.
1. The current age of your child:____years _____ months
2. What grade is your child in:_____________
3. Is he or she in full-time special education:___Yes ___No
4. Is he or she receiving resources services: ___Yes ___No
5. Does he or she have an IEP (Individualized Education Plan): ___Yes ___No
6. Has your child had any of the following services, and if so, for how long:
Physical Therapy: If Yes, for how long
__Yes __No ___Less than 1 year
___Greater than 2 years
Occupational Therapy: If Yes, for how long
__Yes __ No ___Less than 1 year
___Greater than 2 years
Speech Therapy: If Yes, for how long
__Yes __No ___Less than 1 year
___Greater than 2 years
Other Services: (please explain)
For how long were other services were received:Less than 1 year
Greater than 2 years
7. Has your child ever been diagnosed with a learning disability? ___Yes ___No
8. Please indicate with a check mark if your child has ever been diagnosed with:
___ Autism spectrum disorder including Aspergers Syndrome
___ Motor Apraxia
___ Sensory Integration Disorder
___ Language delay
___ Verbal Apraxia
___ Mental Retardation
___ Cerebral Palsy
___ Behavior Disorder
___ Other diagnosis – Please explain
9. At what age did your child walk well on his own: _____ months old
10. Please indicate with a check mark any of the following that describe your child currently:
___Walks independently with good coordination
___Walks independently but is clumsy
___Uses a walker, cane or crutches to walk
___Uses a wheelchair
___Uses a stroller
___Rolls/crawls to get around
___Wears custom shoe inserts
___Wears ankle/foot braces
11. Please indicate with a check mark any of the following that describe your child currently:
___Clumsy or poor motor coordination
___Difficulty with reading
___Difficulty with math
This concludes the survey – please follow the directions below.
Please place this questionnaire and the consent form you signed in the addressed postage paid envelope provided. Then drop in the mail at your earliest convenience.