Hand Strength, Handwriting, and Functional Skills in
Children With Autism
Michele L. Alaniz, Eleanor Galit, Corina Isabel Necesito,
Emily R. Rosario
MeSH TERMS
activities of daily living
autistic disorder
hand strength
handwriting
pinch strength
OBJECTIVE. To establish hand strength development trends in children with autism and to investigate
correlations between grip and pinch strength, components of handwriting, and functional activities in children
with and without autism.
METHOD. Fifty-one children were divided into two groups: typically developing children and children on
the autism spectrum. Each child completed testing for pinch and grip strength, handwriting legibility, pencil
control, and independence in functional activities.
RESULTS. The children with autism followed the same strength development trends as the typically developing children. Grip strength correlated with pencil control in both groups and with handwriting legibility
in the typically developing children but not in the children with autism. Grip and pinch strength correlated
with independence with functional activities in both groups.
CONCLUSION. This study provides evidence that grip and pinch strength are important components in
developing pencil control, handwriting legibility, and independence with functional fine motor tasks.
Alaniz, M. L., Galit, E., Necesito, C. I., & Rosario, E. R. (2015). Hand strength, handwriting, and functional skills in children
with autism. American Journal of Occupational Therapy, 69, 6904220030. http://dx.doi.org/10.5014/ajot.2015.016022
Michele L. Alaniz, OTR/L, is Occupational Therapist
and Clinical Supervisor, Casa Colina Hospital and Centers
for Healthcare, Pomona, CA.
Eleanor Galit, is Research Assistant, Casa Colina
Hospital and Centers for Healthcare, Pomona, CA.
Corina Isabel Necesito, MS, OTR/L, is Occupational
Therapist, Casa Colina Hospital and Centers for
Healthcare, Pomona, CA.
Emily R. Rosario, PhD, is Director of Research
Institute, Casa Colina Hospital and Centers for Healthcare,
Pomona, CA; [email protected]
D
ysgraphia and delays in functional living skills are well established in the
literature as impairments affecting children on the autism spectrum (AbuDahab, Skidmore, Holm, Rogers, & Minshew, 2013; Frith, Morton, & Leslie,
1991; Fuentes, Mostofsky, & Bastian, 2009; Kushki, Chau, & Anagnostou,
2011). As part of the evaluation and treatment process, pinch and grip strength
are often measured (Engel-Yeger & Rosenblum, 2010; Ertem et al., 2005) because of the assumption of a correlation between strength and occupational
performance. Previous studies have established that children with autism have
weaker grip strength than typically developing children (Abu-Dahab et al., 2013;
Hardan, Kilpatrick, Keshavan, & Minshew, 2003; Williams, Goldstein, &
Minshew, 2006). In this study, we sought to investigate the correlation between
grip and pinch strength and functional performance in typically developing
children and children on the autism spectrum. We also sought to establish developmental trends for pinch and grip strength in children with autism.
Strength and Handwriting
Pinch and grip strength may influence performance in a variety of childhood
tasks. The fine motor task that dominates a child’s school day is handwriting.
Children on the autism spectrum often have poor handwriting legibility
(Fuentes et al., 2009), which hinders their academic achievement (Cahill, 2009;
Feder & Majnemer, 2007). Handwriting is a complex task, and many underlying
skills contribute to the development of legible penmanship. Handwriting
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remediation is as complex as the skill itself, and there is
quite a bit of diversity in the activities included in a handwriting remediation program.
Most occupational therapy practitioners report using
an eclectic approach (Feder, Majnemer, & Synnes, 2000;
Woodward & Swinth, 2002) that blends sensory feedback, direct handwriting instruction, and fine motor development into a comprehensive handwriting intervention
(Case-Smith, 2002; Peterson & Nelson, 2003). Within
this eclectic approach, practitioners often include activities
that target the development of pinch strength. In fact,
research supports the practice of measuring pinch strength
as part of the evaluation process for dysgraphia (Engel-Yeger
& Rosenblum, 2010). Despite this common practice,
research does not provide consistent, reliable information on
pinch strength norms for children, and no correlation
between pinch strength and handwriting legibility has
been established for children with disabilities.
Research instead has focused primarily on evaluating
the effectiveness of a variety of handwriting remediation
techniques (Denton, Cope, & Moser, 2006). Research has
also focused on determining the relationship between
handwriting and underlying deficits such as grasp pattern
(Falk, Tam, Schwellnus, & Chau, 2010), eye–hand
coordination, visuomotor integration, and in-hand manipulation (Case-Smith, 2002; Cornhill & Case-Smith, 1996;
Dennis & Swinth, 2001; Feder & Majnemer, 2007). However, little research has addressed the correlation between
pinch and grip strength and handwriting performance.
Engel-Yeger and Rosenblum (2010) assessed the correlation between tripod pinch strength (palmar pinch) and
dysgraphia and found that deterioration in tripod strength
was associated with a significant deterioration in handwriting processes. The study sample, however, included
students with at least average intelligence and no neurological or perceptual–motor problems. No research to
date has examined the association of pinch and grip
strength with handwriting in children with autism.
Strength and Functional Activities
Whereas handwriting is an important childhood task in
the academic environment, self-care activities are an important childhood task in the home environment. Many
self-care skills, such as manipulating fasteners, opening
packages, and tying shoes, require pinch strength and fine
motor control. Limited research has investigated the relationship between pinch and grip strength and functional
performance. Li-Tsang (2003) found that dexterity, not
hand strength, correlated with functional deficits and fine
motor delays in children with neurological motor dis-
orders. Studies have established that children with autism
often experience delays in achieving independence with
daily living skills (Green & Carter, 2014; Jasmin et al.,
2009; Liss et al., 2001) and that these delays correlate
with age, IQ, and language and sensorimotor skills. These
studies did not assess hand strength to determine whether
a link exists between delays in functional independence
and grip and pinch strength.
Pinch and Grip Strength Norms and Trends
Pinch and grip strength norms have been the subject of
study for several decades. In the mid-1980s, researchers
began to use a standardized approach to gather strength
measurements that included a positioning protocol recommended by the American Society of Hand Therapists
(ASHT; Fess & Moran, 1981). The ASHT recommended that the participant be seated with feet flat on the
floor and a 90˚ bend in the hips, the shoulder adducted
and neutrally rotated, the elbow flexed to 90˚, the forearm in neutral position, the wrist between 0˚ and 90˚ and
ulnar deviation between 0˚ and 15˚, and the measurement
tool supported by the examiner. They also recommend that
three consecutive trials be measured and the mean of the
three trials reported.
When examining the research from 1975 to 2014 to
determine pinch strength norms for children, we found
only six studies that included a reliable measurement tool;
followed the ASHT protocol; and gathered pertinent
information about gender, age, and hand dominance
(Bear-Lehman, Kafko, Mah, Mosquera, & Reilly, 2002;
Butterfield, Lehnhard, Loovis, Coladarci, & Saucier,
2009; Mathiowetz, Wiemer, & Federman, 1986; Molenaar,
Selles, Schreuders, Hovius, & Stam, 2008; Surrey
et al., 2001; Yim, Cho, & Lee, 2003). Studies have firmly
established that grip and pinch strength increase with age
(Ager, Olivett, & Johnson, 1984; Bear-Lehman et al.,
2002; Butterfield et al., 2009; De Smet & Decramer,
2006; Imrhan & Loo, 1989; Lee-Valkov, Aaron,
Eladoumikdachi, Thornby, & Netscher, 2003; Mathiowetz
et al., 1986; Molenaar et al., 2008; Surrey et al., 2001;
Yim et al., 2003). Evaluations of other trends in strength
development have yielded inconsistent findings. The influence of hand dominance and gender on hand strength
development is under debate.
Research is almost completely silent on the topic of
pinch and grip strength norms in children with disabilities.
Broadhead (1975) indicated that students with disabilities are able to generate statistically reliable scores.
The grip scores for children with disabilities generally
followed the same trends identified in the population as
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a whole; however, a standardized positioning protocol
and measurement tool with proven reliability were not
used. Recent studies found that children with autism have
lower grip strength than their typically developing peers
(Abu-Dahab et al., 2013; Hardan et al., 2003; Kern et al.,
2013; Williams et al., 2006). However, these studies do
not detail factors such as hand dominance and gender or
include pinch measurements in the findings. Moreover,
they do not report the positioning protocol followed
when obtaining strength measurements.
Research Questions
In this study, we evaluated the relationship between grip
and pinch strength and handwriting and independence
with functional activities in typically developing children
and children on the autism spectrum. We also sought to
establish developmental trends for pinch and grip strength
in children with autism. This study sought to answer the
following research questions:
• Does grip and pinch strength development in children
with autism follow the same trends as in typically developing children?
• Does grip and pinch strength correlate with handwriting legibility in typically developing children and children with autism?
• Does grip and pinch strength correlate with pencil
control in typically developing children and children
with autism?
• Does grip and pinch strength correlate with independence with functional activities in typically developing
children and children with autism?
Method
Participants
Typically developing children (n 5 24) and children on
the autism spectrum (as reported by a physician or parent;
n 5 27), aged 4–10 yr old, were included in the study if
they were able to understand and follow directions and if
they were able to complete the majority of the testing.
Children who were unable to complete the majority of the
testing because of severe visual, cognitive, or motor impairments were excluded (2 children were excluded for this
reason). None of the participants in the autism group were
reported to have Rett syndrome or childhood disintegrative disorder; children with pervasive developmental disorder not otherwise specified were included.
Participants with autism were recruited from among
the clients currently receiving therapy services at an out-
patient pediatric clinic in Southern California. Flyers were
posted at the clinic and given to parents of current clients.
In addition, clinicians recommended participation in the
study when they felt it was appropriate for their client.
Typically developing participants were recruited using
flyers and emails to hospital employees; therefore, the
sample of typically developing children was composed
primarily of employees’ children. After approval from the
institutional review board, full consent and assent were
obtained for all children participating in the study. Participants were divided into two groups for analysis: typically
developing children and children on the autism spectrum.
Instruments
Grip and pinch strength were measured using a Sammons
Preston Jamar hand dynamometer and pinch meter (Patterson Medical, Warrenville, IL). These instruments were
calibrated on an annual basis to ensure proper measurement.
The Beery–Buktenica Developmental Test of Visual–
Motor Integration (VMI) Motor Coordination subtest was
used to assess pencil control (Beery & Beery, 2004). The
VMI is a standardized test used for both research and
clinical purposes in children aged 2–18 yr. The VMI has
been used extensively in the United States and other
countries and demonstrates high psychometric properties
(test–retest reliability r 5 .92, Cronbach’s a 5 .86, construct validity 5 .84; Beery & Beery, 2004). The Evaluation of Children’s Handwriting (ETCH; Amundson,
1995) was used to measure handwriting legibility. The
ETCH has shown good test–retest reliability (r 5 .85–.90)
and validity (r 5 .86; Diekema, Deitz, & Amundson,
1998; Feder & Majnemer, 2007).
A functional questionnaire was designed for this research study based on activities children aged 4 yr and older
could complete. A total of 27 items in four domains
assessed dressing, mealtime, grooming, and miscellaneous
activities. Caregivers rated their child’s independence in
functional skills requiring pinch or grip strength (e.g.,
opens a twist-off bottle top with closed seal, tears open
a small snack, manipulates snaps) on a 5-point scale (4 5
independent, 3 5 completes with encouragement, 2 5 needs
minimal assistance, 1 5 needs maximum assistance, and
0 5 unable to complete).
Procedure
Participants were tested at the outpatient pediatric clinic.
Right and left grip and pinch strength were measured
consecutively using the ASHT positioning protocol. Effort
and understanding were documented for each participant on
a 3-point scale (1 5 none, 2 5 poor, 3 5 average) during
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the strength testing. Each participant was given three consecutive trials for grip strength and lateral, palmar, and tip
pinch strength. The VMI Motor Coordination subtest was
administered to assess pencil control. Handwriting legibility
was assessed with the ETCH, specifically the Upper Case,
Lower Case, and Numbers subtests. Only participants age
6 yr and older participated in ETCH testing. The functional questionnaire was provided to participants’ caregivers
to complete.
Total testing took approximately 30 min to complete.
Research assistants and experienced occupational therapists
administered all tests; research assistants had been trained by
occupational therapists and supervised until they established
proficiency with all test procedures. One research assistant
completed the majority of testing. In all cases, the research
assistants followed a 3-step training procedure. First, they
observed an occupational therapist administering and
scoring the assessments. Then they administered the
assessments to the therapist until proficiency was established.
Once proficient with the therapist, assistants administered
assessments to the participants while being assisted by the
occupational therapist to ensure accuracy. Once competence
was established in administering the assessments to the
participants, the assistants worked independently. All tests
were scored by two assessors independent of each other.
Interrater agreement was 91%, and when scores differed, the
occupational therapist’s score was used.
66% male and 34% female; the participants with autism
were 78% male, however, and the typically developing
participants were 54% male. These proportions are
consistent with those in the general population of both
typically developing children and children with autism.
Grip and Pinch Strength
In this study, the typically developing children and those
with autism showed increasing grip and pinch strength
with increasing age (Figure 1). Comparison of the slopes
of the typically developing children and those with autism shows a trend toward differences, with the grip
strength of children with autism showing greater variability as age increased. However, no significant differences are evident when comparing the slope or the means
by age (Table 1). We also found no significant association
among gender, hand dominance, and strength values.
In addition to examining the developmental trends in
hand strength, we assessed effort and understanding to determine their impact on hand strength measurements. Effort
correlated with grip strength in the sample as a whole, F (1,
49) 5 6.7, p 5 .015, but not within the typically developing
or autism groups. Similarly, direction comprehension correlated with grip strength in the sample as a whole, F(1, 49) 5
4.6, p 5 .048, but not within the typically developing group;
however, it did correlate within the autism group (p 5 .04).
Hand Strength and Pencil Control
Data Analysis
Grip and pinch values were averaged from three consecutive trials. The mean of the three trials was used for
analysis, with numbers rounded down if the score fell
between whole numbers. The coefficient of variation (CV)
was calculated to assess the variability of measurements for
each child. If the CV was greater than 20%, the outlier was
removed. VMI raw scores were converted to T scores for
analysis, the functional skills assessment was represented
as the percent of completed items demonstrating independence, and the ETCH scores were represented as
a legibility percentage. Linear regressions were run to
evaluate relationships among strength, pencil control,
handwriting legibility, and functional abilities.
Results
Participants
The mean age of the participants was 6 yr 9 mo (± 1.75
yr), and 90% of the participants were right handed. Of
the 51 participants, 27 had been diagnosed with autism
and 24 were typically developing. Overall, the sample was
In the sample as a whole, grip strength correlated with pencil
control as measured by the VMI Motor Coordination
subtest. Grip strength correlated with pencil control in the
typically developing group, F(1, 22) 5 8.1, p 5 .008, and
the autism group, F(1, 25) 5 7.9, p 5 .01. Pinch strength
did not correlate with pencil control for the sample as
a whole or within the typically developing or autism groups.
Grip and Pinch Strength and Handwriting
In participants who were able to complete the ETCH (n 5
32, 63%), grip strength correlated with handwriting
legibility using a mean percentage of legibility for Upper
Case, Lower Case, and Numbers, F(1, 30) 5 10.9, p 5
.002. Grip strength correlated with handwriting legibility
in the typically developing group (n 5 16), F(1, 14) 5
6.1, p 5 .03, but not in the autism group (n 5 16),
F(1, 14) 5 3.2, p 5 .09; see Figure 2. Pinch strength did
not correlate with handwriting in either group.
Grip and Pinch Strength and Functional Abilities
Grip strength and lateral, palmar, and tip pinch strength
correlated with functional activities when examining the
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Figure 1. (A) Grip strength and pinch strength—(B) tip, (C) lateral, and (D) palmar—increase with age.
Note. ASD 5 children with autism spectrum disorder; TD 5 typically developing children.
p
p < .05.
sample as a whole. When looking at the typically developing and autism groups separately, however, we observed a significant relationship between only grip strength
and lateral pinch strength and functional activities (Figure
3). The functional activities most significantly correlated
with grip strength included tears open a small snack, F(1,
49) 5 6.6, p 5 .02; opens twist-off bottle top with closed
seal, F(1, 49) 5 13.1, p 5 .004; cuts food with knife,
F(1, 49) 5 5.2, p 5 .04; puts straw in juice box,
F(1, 49) 5 9.3, p 5 .01; takes cap off toothpaste, F(1, 49) 5
5.7, p 5 .038; squeezes toothpaste on toothbrush,
F (1, 49) 5 8.2, p 5 .01; turns key to unlock door,
F (1, 49) 5 8.7, p 5 .01; and turns doorknob to open
door, F(1, 49) 5 6.6, p 5 .02.
Discussion
This study investigated the correlation between grip and
pinch strength and proficiency in functional activities,
including handwriting legibility and functional tasks, in
children with and without autism aged 4–10 yr. It also
sought to establish grip and pinch strength trends in
children with autism. Children with autism followed the
same established developmental trends in strength as the
typically developing children, although their strength
scores were lower than their typically developing peers in
all measurements. Grip strength correlated with pencil
control in both groups and with handwriting legibility in
the typically developing children but not in the children
with autism. Grip and pinch strength correlated with independence in functional activities in both groups.
Grip and Pinch Strength Trends
Our participants, including the children with autism,
followed the grip and pinch strength trends established in
the literature (Ager et al., 1984; Bear-Lehman et al.,
2002; Butterfield et al., 2009; De Smet & Decramer,
Table 1. Mean Grip and Pinch Strength in Pounds, by Age
Sample Size
Age Category
TD
ASD
Grip Strength
Tip Pinch Strength
Lateral Pinch Strength
Palmar Pinch Strength
TD
ASD
TD
ASD
TD
ASD
TD
ASD
4–6 yr
8
11
16.5 ± 1.2
13.3 ± 1.9
2.1 ± 0.3
1.2 ± 0.4
5.1 ± 0.6
3.8 ± 0.6
3.2 ± 0.6
2.5 ± 0.6
6–8 yr
10
11
21.1 ± 1.7
18.3 ± 1.7
5.0 ± 1.5
3.1 ± 1.6
6.5 ± 0.6
5.9 ± 0.6
5.7 ± 0.6
4.2 ± 0.7
8–10 yr
6
5
30.5 ± 1.4
22.6 ± 5
5.6 ± 0.9
4.0 ± 0.9
8.9 ± 0.6
8.1 ± 1.5
8.4 ± 1.2
7.5 ± 1.5
Note. ASD 5 children with autism spectrum disorder; TD 5 typically developing children.
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Figure 2. Grip strength correlates with handwriting legibility:
Percentage of legibility as measured with the Evaluation of
Children’s Handwriting (ETCH) significantly correlated with grip
strength in typically developing children.
Note. ASD 5 children with autism spectrum disorder; TD 5 typically
developing children.
p
p < .05.
2006; Imrhan & Loo, 1989; Lee-Valkov et al., 2003;
Mathiowetz et al., 1986; Molenaar et al., 2008; Surrey
et al., 2001; Yim et al., 2003). We found that children
with and without autism grew stronger with age. In addition, we did not observe a significant difference between boys and girls in their pinch and grip strength
scores; this finding is still debated in the literature (Ager
et al., 1984; Bear-Lehman et al., 2002; De Smet &
Decramer, 2006; Imrhan & Loo, 1989; Mathiowetz
et al., 1986; Molenaar et al., 2008; Yim et al., 2003). Also
unclear based on the current literature is the impact of
hand dominance on strength in children. Our findings
were consistent with those of studies that found a non-
significant association between hand dominance and
pinch and grip strength (Ager et al., 1984; Bear-Lehman
et al., 2002; Butterfield et al., 2009; De Smet &
Decramer, 2006; Lee-Valkov et al., 2003; Mathiowetz
et al., 1986).
A finding unique to this study is the establishment of
new trends for children with autism. Our findings indicate
that no statistically significant difference exists in pinch
strength between typically developing children and children with autism. We found a trend, however, toward
increased grip strength in the typically developing children
compared with the children with autism. The divergence
between the groups increased with age, indicating that the
gap between typically developing children and children
with autism widens as children grow older. A larger sample
size is needed to more clearly define this relationship.
Also of note, we found that children with autism were
less reliable in producing consistent scores across three
trials during the strength measurements; 43% of the
children with autism, compared with 20% of the typically
developing children, had a CV greater than 20%. Characteristics inherent in the autism diagnosis, such as communication delays, social delays, and stereotypical behaviors,
likely interfered with the children’s ability to produce
consistent results.
Both right and left grip strength correlated with
amount of effort in the sample as a whole; in other words,
the more effort put forth, the higher the grip strength
scores. However, effort did not correlate with strength in
the typically developing or autism groups individually.
This finding may indicate that although the amount of
effort put forth during testing had an influence on strength
scores, it was a minor influence.
Right and left grip strength also correlated with
comprehension of testing directions in the sample as
a whole. For the typically developing group, however,
Figure 3. (A) Grip strength and (B) lateral pinch strength correlate with functional abilities.
Note. ASD 5 children with autism spectrum disorder; TD 5 typically developing children.
p
p < .05.
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direction comprehension did not correlate with strength;
these children almost always seemed to understand the
directions. In contrast, direction comprehension did
correlate with strength in the children with autism. Because communication delays are intrinsic to the diagnosis
of autism, these children are particularly vulnerable to not
understanding directions, compromising their ability to
reliably participate in strength testing (American Psychiatric
Association, 2000).
Correlations Between Functional Measures and
Hand Strength
Previous studies have established the correlation between
pencil control and handwriting legibility (Cornhill &
Case-Smith, 1996). Our study sought to establish a correlation between hand strength and pencil control measured using the VMI Motor Coordination subtest. For
the sample as a whole, grip strength correlated with T
scores on the VMI Motor Coordination subtest, indicating that the stronger the grip strength, the better the
pencil control. This correlation was observed in both the
typically developing and autism groups.
Interestingly, pinch strength did not correlate with
pencil control. We hypothesize that this finding is attributable to the sensitivity of the instruments used to
measure grip and pinch strength. We collected strength
data using a manual-read, rather than digital, dynamometer and pinch gauge. To maintain consistency
throughout the research, if the measurement fell between
whole numbers, the score was rounded down to the nearest
whole number. Pinch strength scores are particularly
susceptible to low sensitivity because the numbers are so
small. Because we did observe a correlation between grip
strength and pinch strength, however, pinch strength
might also have correlated with pencil control were it not
for the limitations of the sample size and measurement
sensitivity.
The relationship between strength and handwriting
legibility was assessed using the ETCH. In the sample as
a whole, grip strength correlated with handwriting legibility.
The typically developing children demonstrated a correlation between strength and legibility, a finding that agrees
with previous work in which a correlation was observed
between tripod pinch strength and dysgraphia in typically
developing children (Engel-Yeger & Rosenblum, 2010).
However, the autism group did not demonstrate a correlation between hand strength and handwriting legibility. Contributing to this finding may be the fact that
only 78% of our participants with autism who were
eligible to complete the ETCH were able to complete the
ETCH testing, whereas 100% of the typically developing
participants who were eligible to complete the ETCH
did so.
Moreover, handwriting is a complex skill, and many
components influence handwriting development. Cognitive demands, visual–perceptual demands, and visual–
motor integration, along with fine motor strength and
development, all influence handwriting development.
Our findings indicate that although hand strength does
influence handwriting legibility, other, more salient factors also influence legibility, making hand strength less
critical in children with autism.
Finally, we examined the relationship between functional abilities and grip and pinch strength. To do this, we
developed a questionnaire for this research asking the
parents to rate their child’s independence in a variety of fine
motor functional tasks. In the sample as a whole, functional abilities correlated with lateral, palmar, and tip pinch
strength in both the right and left hands. A variety of
correlations emerged in examining the groups separately.
In the typically developing group, nondominant grip
strength and dominant palmar pinch strength correlated
with independence in functional tasks. In the autism
group, right and left grip strength, right and left lateral
pinch strength, and nondominant palmar pinch strength
correlated with one another. To further define the functional activities that more strongly correlated with grip and
pinch strength, we performed a discriminant analysis (see
Table 1). Grip and pinch strength were strongly correlated
with independence in functional activities in both groups.
Study Limitations
The primary limitation of this study is the sample size,
particularly when the sample is divided by sex, age, and
diagnosis. In addition, because only 78% of the children
with autism were able to complete the ETCH, the sample
size for this analysis was even further reduced. Although we
are able to draw some conclusions regarding trends and
relationships, we are limited in making more specific
statements about gender differences and age-related
changes. In addition, we believe that the pinch strength
data were limited by the sensitivity of the measurement
tool. Because we were not able to record values to a decimal place, our analysis of pinch strength was limited.
However, because the measurement tool we used is
commonly used clinically, our pinch data carry some
clinical validity. We were also limited in our interpretation
of the relationship between grip strength and pencil
control. Although children with visual impairments were
excluded, we did not complete any visuoperceptual testing. Therefore, when examining the results regarding
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pencil control, we were not able to rule out the possible
contribution of visuoperceptual deficits.
Implications for Occupational
Therapy Practice
The findings of this study have the following implications
for occupational therapy practice:
• The amount of effort put forth during testing has
a minor influence on pinch and grip strength measurements in typically developing children and children
with autism.
• Whether children understand the directions is important when taking grip and pinch strength measurements, particularly with children who have autism.
Researchers should consider calculating the CV and
either dropping outlier scores or adding trials to get
closer to a true score.
• Grip strength correlates with pencil control.
• Grip strength does not correlate with handwriting
legibility in children with autism.
• Grip strength correlates with handwriting legibility in
typically developing children.
• Grip and pinch strength correlate with functional
abilities. s
Acknowledgments
The authors thank Dr. Loverso and the Casa Colina Board
of Directors, Cindy Sendor, the therapists in the children’s
department (Lacy Wright, Sarah Yun, Kristin Horn, and
Yovana Guzman), and the Casa Colina Hospital and
Centers for Healthcare Foundation for supporting this
research. We also thank Brianna Bentley and Betsy Diaz
for their involvement in study recruitment and testing.
References
Abu-Dahab, S. M., Skidmore, E. R., Holm, M. B., Rogers,
J. C., & Minshew, N. J. (2013). Motor and tactile–
perceptual skill differences between individuals with
high-functioning autism and typically developing individuals
ages 5–21. Journal of Autism and Developmental Disorders,
43, 2241–2248. http://dx.doi.org/10.1007/s10803-0111439-y
Ager, C. L., Olivett, B. L., & Johnson, C. L. (1984). Grasp and
pinch strength in children 5 to 12 years old. American
Journal of Occupational Therapy, 38, 107–113. http://dx.
doi.org/10.5014/ajot.38.2.107
American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). Arlington, VA: Author.
Amundson, S. J. (1995). Evaluation Tool of Children’s Handwriting:
ETCH examiner’s manual. Homer, AK: O.T. Kids.
Bear-Lehman, J., Kafko, M., Mah, L., Mosquera, L., & Reilly, B.
(2002). An exploratory look at hand strength and hand size
among preschoolers. Journal of Hand Therapy, 15, 340–346.
http://dx.doi.org/10.1016/S0894-1130(02)80005-9
Beery, K. E., & Beery, N. A. (2004). The Beery–Buktenica
Developmental Test of Visual–Motor Integration: Administration, scoring, and teaching manual (5th ed.). Minneapolis: NCS Pearson.
Broadhead, G. D. (1975). Dynamometric grip strength in
mildly handicapped children. Rehabilitation Literature,
36, 279–283.
Butterfield, S. A., Lehnhard, R. A., Loovis, E. M., Coladarci,
T., & Saucier, D. (2009). Grip strength performances by
5- to 19-year-olds. Perceptual and Motor Skills, 109,
362–370. http://dx.doi.org/10.2466/pms.109.2.362-370
Cahill, S. M. (2009). Where does handwriting fit in? Strategies to support academic achievement. Intervention in
School and Clinic, 44, 223–228. http://dx.doi.org/10.1177/
1053451208328826
Case-Smith, J. (2002). Effectiveness of school-based occupational therapy intervention on handwriting. American
Journal of Occupational Therapy, 56, 17–25. http://dx.
doi.org/10.5014/ajot.56.1.17
Cornhill, H., & Case-Smith, J. (1996). Factors that relate to
good and poor handwriting. American Journal of Occupational Therapy, 50, 732–739. http://dx.doi.org/10.5014/
ajot.50.9.732
Dennis, J. L., & Swinth, Y. (2001). Pencil grasp and children’s
handwriting legibility during different-length writing tasks.
American Journal of Occupational Therapy, 55, 175–183.
http://dx.doi.org/10.5014/ajot.55.2.175
Denton, P. L., Cope, S., & Moser, C. (2006). The effects of
sensorimotor-based intervention versus therapeutic practice
on improving handwriting performance in 6- to 11-yearold children. American Journal of Occupational Therapy, 60,
16–27. http://dx.doi.org/10.5014/ajot.60.1.16
De Smet, L., & Decramer, A. (2006). Key pinch force in children. Journal of Pediatric Orthopaedics, Part B, 15, 426–427.
http://dx.doi.org/10.1097/01.bpb.0000218022.43277.f1
Diekema, S. M., Deitz, J., & Amundson, S. J. (1998). Test–
retest reliability of the Evaluation Tool of Children’s
Handwriting–Manuscript. American Journal of Occupational Therapy, 52, 248–255. http://dx.doi.org/10.5014/
ajot.52.4.248
Engel-Yeger, B., & Rosenblum, S. (2010). The effects of protracted graphomotor tasks on tripod pinch strength and
handwriting performance in children with dysgraphia.
Disability and Rehabilitation, 32, 1749–1757. http://dx.
doi.org/10.3109/09638281003734375
Ertem, K., Harma, A., Cetin, A., Elmali, N., Yologlu, S.,
Bostan, H., & Sakarya, B. (2005). An investigation of hand
dominance, average versus maximum grip strength, body
mass index and ages as determinants for hand evaluation.
Isokinetics and Exercise Science, 13, 223–227.
Falk, T. H., Tam, C., Schwellnus, H., & Chau, T. (2010). Grip
force variability and its effects on children’s handwriting legibility, form, and strokes. Journal of Biomechanical Engineering, 132, 114504. http://dx.doi.org/10.1115/1.4002611
6904220030p8
Downloaded From: http://ajot.aota.org/ on 03/03/2016 Terms of Use: http://AOTA.org/terms
July/August 2015, Volume 69, Number 4
Feder, K. P., & Majnemer, A. (2007). Handwriting development, competency, and intervention. Developmental Medicine and Child Neurology, 49, 312–317. http://dx.doi.org/
10.1111/j.1469-8749.2007.00312.x
Feder, K., Majnemer, A., & Synnes, A. (2000). Handwriting:
Current trends in occupational therapy practice. Canadian
Journal of Occupational Therapy, 67, 197–204. http://dx.
doi.org/10.1177/000841740006700313
Fess, E. E., & Moran, C. (1981). Clinical assessment recommendations. Indianapolis: American Society of Hand Therapists.
Frith, U., Morton, J., & Leslie, A. M. (1991). The cognitive
basis of a biological disorder: Autism. Trends in Neurosciences, 14, 433–438. http://dx.doi.org/10.1016/01662236(91)90041-R
Fuentes, C. T., Mostofsky, S. H., & Bastian, A. J. (2009).
Children with autism show specific handwriting impairments. Neurology, 73, 1532–1537. http://dx.doi.org/10.1212/
WNL.0b013e3181c0d48c
Green, S. A., & Carter, A. S. (2014). Predictors and course of
daily living skills development in toddlers with autism
spectrum disorders. Journal of Autism and Developmental Disorders, 44, 256–263. http://dx.doi.org/10.1007/
s10803-011-1275-0
Hardan, A. Y., Kilpatrick, M., Keshavan, M. S., & Minshew,
N. J. (2003). Motor performance and anatomic magnetic
resonance imaging (MRI) of the basal ganglia in autism.
Journal of Child Neurology, 18, 317–324. http://dx.doi.
org/10.1177/08830738030180050801
Imrhan, S. N., & Loo, C. H. (1989). Trends in finger pinch
strength in children, adults, and the elderly. Human Factors, 31, 689–701.
Jasmin, E., Couture, M., McKinley, P., Reid, G., Fombonne,
E., & Gisel, E. (2009). Sensori-motor and daily living
skills of preschool children with autism spectrum disorders. Journal of Autism and Developmental Disorders, 39,
231–241. http://dx.doi.org/10.1007/s10803-008-0617-z
Kern, J. K., Geier, D. A., Adams, J. B., Troutman, M. R.,
Davis, G. A., King, P. G., & Geier, M. R. (2013). Handgrip
strength in autism spectrum disorder compared with controls.
Journal of Strength and Conditioning Research, 27, 2277–2281.
http://dx.doi.org/10.1519/JSC.0b013e31827de068
Kushki, A., Chau, T., & Anagnostou, E. (2011). Handwriting
difficulties in children with autism spectrum disorders: A scoping review. Journal of Autism and Developmental Disorders, 41,
1706–1716. http://dx.doi.org/10.1007/s10803-011-1206-0
Lee-Valkov, P. M., Aaron, D. H., Eladoumikdachi, F., Thornby,
J., & Netscher, D. T. (2003). Measuring normal hand
dexterity values in normal 3-, 4-, and 5-year-old children
and their relationship with grip and pinch strength. Journal
of Hand Therapy, 16, 22–28. http://dx.doi.org/10.1016/
S0894-1130(03)80020-0
Liss, M., Harel, B., Allen, D., Dunn M., Feinstein, C., Morris,
R., . . . Rapin, I. (2001). Predictors and correlates of
adaptive functioning in children with developmental disorders. Journal of Autism and Developmental Disorders, 31,
219–230.
Li-Tsang, C. W. P. (2003). The hand function of children with
and without neurological motor disorders. British Journal
of Developmental Disabilities, 49, 99–110. http://dx.doi.
org/10.1179/096979503799104093
Mathiowetz, V., Wiemer, D. M., & Federman, S. M. (1986).
Grip and pinch strength: Norms for 6- to 19-year-olds.
American Journal of Occupational Therapy, 40, 705–711.
http://dx.doi.org/10.5014/ajot.40.10.705
Molenaar, H. M., Selles, R. W., Schreuders, T. A., Hovius,
S. E., & Stam, H. J. (2008). Reliability of hand strength
measurements using the Rotterdam Intrinsic Hand Myometer in children. Journal of Hand Surgery, 33, 1796–1801.
http://dx.doi.org/10.1016/j.jhsa.2008.07.018
Peterson, C. Q., & Nelson, D. L. (2003). Effect of an occupational intervention on printing in children with economic disadvantages. American Journal of Occupational
Therapy, 57, 152–160. http://dx.doi.org/10.5014/ajot.57.2.152
Surrey, L. R., Hodson, J., Robinson, E., Schmidt, S., Schulhof,
J., Stoll, L., & Wilson-Diekhoff, N. (2001). Pinch
strength norms for 5- to 12-year-olds. Physical and Occupational Therapy in Pediatrics, 21, 37–49. http://dx.doi.
org/10.1080/J006v21n01_04
Williams, D. L., Goldstein, G., & Minshew, N. J. (2006).
Neuropsychologic functioning in children with autism:
Further evidence for disordered complex informationprocessing. Child Neuropsychology, 12, 279–298. http://
dx.doi.org/10.1080/09297040600681190
Woodward, S., & Swinth, Y. (2002). Multisensory approach to
handwriting remediation: Perceptions of school-based occupational therapists. American Journal of Occupational
Therapy, 56, 305–312. http://dx.doi.org/10.5014/ajot.
56.3.305
Yim, S. Y., Cho, J. R., & Lee, I. Y. (2003). Normative data and
developmental characteristics of hand function for elementary school children in Suwon area of Korea: Grip, pinch
and dexterity study. Journal of Korean Medical Science, 18,
552–558. http://dx.doi.org/10.3346/jkms.2003.18.4.552
The American Journal of Occupational Therapy
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