Signs of Weakness

Signs of Weakness

Signs of Weakness by Age for Primary Care

A surveillance aid for primary care providers to facilitate the identification of signs of muscle weakness in children ages 6 months to 5 years. Failure to meet age-appropriate milestones may be a sign of a serious developmental delay.

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Signs of Weakness by Parent Report

An aid for more effective listening to parents: learn how parents report describing their first concerns about motor development to their care providers.

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Signs of Weakness by Age for Therapists/Specialists

An expanded surveillance aid for therapists, specialists, and other professionals who care for children, to aid in the identification of signs of motor weakness in children ages 6 months to 5 years.

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Know the Signs by Age

Click the icons below to review the signs of weakness by age.

Surveillance and Referral Aid

Target Audiences


Among children (ages 6 months-5 years) referred for services/consultation based on developmental delays, identify those who might have weakness secondary to a neuromuscular disorder.  Listen to parents’ concerns about development. Facilitate early diagnosis of neuromuscular disorders, which is important because it helps target therapies and other interventions, improve outcomes, reduce family distress related to the diagnostic process, and provide the opportunity for accurate genetic counseling.

Use of the Surveillance Aid

  • The guidance in this aid assumes that a therapist/specialist is following the child because he/she has an identified developmental delay and/or hypotonia.  
  • The guidance also assumes that the user understands normal motor development, and evaluates each child in light of his/her overall presentation and developmental history.
  • The recommendations include communicating directly with the primary care provider.  If direct communication is problematic, an alternative approach is to have the parents sign a release and send a copy of your report to the primary care provider.
  • The materials that follow identify “red flags” by age, and suggest when referral for diagnostic evaluation should occur.  In addition to the red flags, this aid includes a discussion of “yellow flags” that contribute to concerns about muscle weakness.
  • This aid is designed for children who were born on or after 38 weeks of gestation.  If a child is born prior to 38 weeks of gestation, please use adjusted age for developmental milestones.

Additional red flags that should prompt a diagnostic evaluation by a specialist, regardless of age:

  • Tongue fasciculations
  • Regression in developmental milestones
  • CK level that is greater than 3x normal

Yellow flags that should increase concern about muscle weakness (taking into account overall development):

  • Any developmental delay: upon noting any developmental delay, evaluate motor development as part of the surveillance and screening
    • Language delay: note that neuromuscular disorders may present with language delays
  • Eating/feeding: children who are very slow at swallowing, sucking, and/or chewing; frequent coughing during feeding; fatigue during feeding or stopping before satisfied; requiring more positional support than usual during feeding
  • Babbling: if a child is not babbling by 10 months, evaluate motor development
  • Fatigue/decreased endurance: tiring during routine tasks (e.g., eating, crawling, climbing, playing) can be an early sign of muscle weakness
  • Frequent falling: frequent falls may be a sign of muscle weakness. Falls tend to be sudden, and are often characterized by collapsing straight down to the floor (not forward or over).

Developmental norms:

  • pull to sit with no head lag*: 50% by 3.5 months, 75% by 4 months, 90% by 6.5 months
  • sitting without support**: 50% by 5.9 months, 75% by 6.7 months, 90% by 7.5 months
  • getting into sitting*: 50% by 8.5 months, 75% by 9.5 months, 90% by 10 months
  • walking alone**: 50% by 12 months, 75% by 13.1 months, 90% by 14.4 months
  • rise to stand from floor: corresponds with time of independent walking
  • runs*: 50% by 16 months, 75% by 18.5 months, 90% by 21 months
  • jump up*: 50% by 2 years, 75% by 2 years 3 months, 90% by 2.5 years
  • hops*: 50% by 3.5 years, 75% by 4 years, 90% by 4 years 3 months

*Denver II **WHO Multicentre Growth Reference Study Group: WHO Motor Development Study

Performing an Exam

Examination for signs of proximal muscle weakness includes:

  • Watching for abdominal breathing or accessory muscle use
  • Evaluating for head lag when pulled to sit, noting biceps resistance (failure of child pulling back when pulled to sit) or inability to voluntarily flex neck when supine
  • Evaluating whether child “slips through the hands” when held suspended (examiner’s hands under the armpits)
  • Stimulating foot and evaluate force of withdrawal movement
  • Watching for difficulty rising from floor (including Gowers maneuver, full or modified)

On exam, look for muscle hypertrophy or atrophy, particularly calves and tongue (calves may also feel abnormally full).

Other physical findings may help distinguish neuromuscular disease (peripheral cause, such as Duchenne muscular dystrophy) from diseases of the brain (central cause, such as cerebral palsy), as shown in the table that follows. The table that follows shows general guidelines, though evaluation requires use of clinical judgment related to the child’s overall developmental history.

Sign Peripheral Cause Central Cause
Chest size May be small with bell shape Usually normal
Facial movement Often weak “myopathic” with high arched palate Usually normal
Tongue fasciculation May be present, particularly in SMA Absent
Tone Reduced tone Reduced tone or increased tone with scissoring
Deep Tendon Reflexes Decreased or absent Increased, may have clonus
Gait Toe walking



Toe walking



It is important to test for signs of motor weakness over time. If a child does not achieve a motor milestone at the expected time, follow up until the milestone is achieved, or until there is sufficient concern or referral. Ask about and evaluate for signs of motor regression.

Supporting Parents

Communication Tips

Clinicians know that it is important to listen to parent/guardian concerns, but in a busy practice it may be difficult to know how to respond when concerns are expressed, and which concerns should raise red flags. Equally complex are discussions in which a provider has to bring up developmental concerns that the parents may or may not share. There is a significant literature about, and provider training in, breaking “bad news” to families. There is less guidance for providers who need to address a possible problem. We provide guidance below that is informed by expert consensus: clinicians and parents who have been through this experience.

Guidance from Bright Futures: “Parents’ perspectives about the needs of their children and whether they view the infant’s behaviors as normal or typical for the child’s age are equally important considerations in developmentally focused anticipatory guidance. Because families vary in their responses and behaviors, the health care professional must learn about these customs and seek to understand parents’ responses and behaviors, even if they differ from those expected in the community context.” Bright Futures, accessed November 2010.

General tips when there are concerns from the provider and/or parents about a child’s motor development:

  • Take time to understand the parents’ concerns. Appreciate that socio-cultural background may affect whether and how parents discuss concerns with providers.
  • Pay attention to the parents’ tone of voice and body language as important communication cues.
  • Explain your own concerns (or why you are not concerned) in plain language.
  • Outline the plan for further assessment. Clearly describe what will happen next and which clinical professionals will be involved.
  • Ask if the parents have any questions. Realize that they may be so overwhelmed or concerned that they will not be able to take in much information, and they may need another opportunity to ask questions in the near future.
  • Ask the parents how they feel about the plan.
  • Respond to their feelings; even a simple reflection of their feelings goes a long way to the parents feeling heard.
  • Reassure parents that you will revisit concerns about motor development until delays are resolved and/or until the cause of the delay is known.

Though these tips may seem obvious, it is easy to overlook basic communication skills and make assumptions about parents’ understanding and perspectives, especially when the providers’ focus is on the child.

  • Communication tips when the parents bring up a concern about motor development
    • Appreciate that most parents are accurate at identifying delays in child development; as noted by the AAP, 80% of parental concerns are correct and accurate.
    • Use active listening. Ask questions to clarify and gather more information, especially if parents present vague concerns about development.
    • Use questioning to take advantage of the fact that parents have opportunities to see children perform gross motor activities that you may not be able to observe in the clinic setting (sustained running, climbing, bike riding, stair climbing, etc).
    • Encourage parents to come to appointments with a list of questions and concerns to help ensure that their needs are met during the visit.
  • Communication if you share the parents’ concerns
    • Clearly explain where you see delays and how your assessment corresponds with or adds to the parents’ stated concerns.


“You’ve told me that you are worried because Derrick isn’t able to get into a sitting position yet, though he is 9 months old. I agree that he’s behind what we’d expect in this milestone. I also notice that although he can sit alone, he’s still wobbly and he needs to use his hands to stay steady.”

  • Talk to parents honestly, though sensitively, about whether your assessment is more consistent with a minor delay that is amenable to quick catch-up, or whether you suspect a more serious delay.


“Derrick should have more strength by now. We need to check into the reason that he is behind. Though it is possible that he might catch up if we didn’t do anything, I think that it’s best that we provide him with some extra help.”

  • As relevant, emphasize that all children are different and that it is difficult to predict whether delays will continue, get better, or get worse; when reasonable, reassure parents that the child is unlikely to suddenly and dramatically get worse (a common concern once delays have been noted).
  • Explain the follow up plan. Describe the timeline and any specialists or therapists who will be involved, their role, and why it is important that they evaluate the child.


I’m going to do a CK test today, which is a simple blood test. Weakness can come from different causes and the CK test may tell whether the cause is his muscles. I’m also going to refer Derrick to a child neurologist, Dr. Smith. She is an expert on things that can cause weakness in children. Some parents hear the word “neurologist” and get really worried, which is understandable—neurologists sometimes care for kids who are really sick, but they also see a lot of kids who do great. We want to make sure that Derrick gets the care he needs as soon as possible, so we can continue to work together to figure out why he is weak and make a plan for next steps.”

  • Finally, keep in mind that your confirmation of the parents’ concerns may raise conflicting feelings, including relief at being heard, worry because you share their concerns, and even anger at you for bringing unwelcome news. Take a few moments to ask about the parents’ feelings.


“I know that this isn’t the news you wanted to hear. How are you feeling right now?….What is your main worry right now?”

  • Communication if you do not share the parents’ concerns

If parents raise concerns that you think are unwarranted or premature, consider the following.

  • Listen to their concerns and use reflective statements so they know you understand their perspective.


“I hear you saying that based on your older son’s age at walking, you are worried that your daughter’s walking is behind.”

  • Explain clearly why you think the child’s motor development is in an acceptable range.


“It’s true that your daughter is later to start walking than your son. But children develop at different speeds, and your daughter is only 12 months old. Only about half of children are walking at 12 months. I’m also reassured that she met all of her other milestones at the right times, and she looks great on her check up today.”

  • Reassure the parents that you will evaluate motor development at each well-child visit.


“I’ll see you and your daughter again in 2 months for her next visit. If she is having any issues with her development, we can talk about next steps. I suspect that she’ll be walking by then, though.”

  • Communications tips when you have concerns and the parents don’t, or if you don’t know if parents have concerns
    • Explore whether the parents have any concerns about development. If this is a first child, ask if the parents know when motor milestones should be achieved. Ask if the parents have noticed any differences among their child’s development and those of siblings/peers.
    • Bring up your concerns as you educate about when milestones should be attained. Emphasize the range in attainment in healthy, “normal” children.


“I have noticed that Derrick isn’t able to get into sitting yet, though he is 9 months old. I also notice that although he can sit alone, he’s still wobbly and he needs to use his hands to stay steady. Though babies develop at different speeds, by 9 months most children are able to sit very steadily and get into sitting by themselves.”

  • Ask if the parents have noticed your concern, or anything else that concerns them about their child’s development.


“Do you see what I mean about Derrick’s sitting?… Tell me how you feel about his development overall.”

  • Ask them how they feel about you bringing up the developmental concern.


“No parent wants to hear that their baby is behind in anything. In a minute we are going to plan what to do, but right now, tell me how you are feeling. What’s your biggest worry?”

  • See the tips under Communication if you share the parents’ concerns, above, for guidance on continuing the discussion.

Additional communication tips for parents who deny a motor delay or are resistant to follow up

  • Confirm (don’t assume) that the parents do not share your perspective. Keep in mind that couples may not agree.
  • Appreciate that resistance or denial may be rooted in fear or anger, influenced by your own bedside manner, and impacted by their socio-cultural perspective. Understand that denial may be a valid coping mechanism to protect the parent from pain or avoid conflict.
  • If a brief “wait and see” time is acceptable, consider asking the parents to look for specific motor milestones for one month, then bring the child back before recommending any follow up. This may allow the parents time to appreciate your area of concern and adjust to the need for follow up. If possible, call to check in with the family after two weeks.
  • When reasonable based on your clinical judgment, reassure the parents that many children benefit from early therapy.
  • Explain the follow up plan. Describe the timeline and any specialists or therapists who will be involved, their role, and why it is important that they evaluate the child.
  • Engage the family as much as possible. Ask if they have questions. Ask if they can re-state in their own words why you have raised a concern.
  • Be transparent about the fact that you and the parents disagree, and that you are still willing to work with them. Try to come to a shared goal, e.g., you all want to do your part to be sure the child develops to his/her highest potential.

Taking a History

Patient History

Specific questions to ask about motor function include:

  • Loss of skills
    • To evaluate for loss of skills, compare to what the child was doing 1/4 of his/her life ago, e.g., if a patient is 12 months, compare to what he/she was doing at 9 months.
  • Difficulty keeping up with peers (e.g., when sitting, walking, running, climbing stairs)
  • Falling/clumsiness
  • Whether child “slips through the hands” when held suspended
  • Difficulty feeding

Review all developmental milestones, including social and language.

Family history

Though a negative family history does not rule out a genetic neuromuscular disease, a family history of neuromuscular disease may be critical in your evaluation. You may wish to consult with a geneticist or genetic counselor at your institution to elicit a thorough family history.

Genetic neuromuscular disorders have a range of inheritance patterns, some of which allow transmission of a gene mutation through unaffected carriers and may result in an affected child with no previous family history. In addition, gene mutations that cause neuromuscular disorders may happen for the first time (de novo) in an affected child.

  • A complete family history should include information about at least 3 generations, a question about consanguinity in the parents, and a summary question about whether anyone else in the family had muscle concerns or weakness.

A three-generation family history in the pediatric context includes information on the child’s generation (i.e., siblings and cousins), the parents’ generation (i.e., the parents and their siblings and cousins), and the grandparents’ generation (i.e., the grandparents and their siblings). Asking about consanguinity (whether the parents are related) is important because consanguinity increases suspicion of an autosomal recessive disorder.

  • Neuromuscular diseases have different inheritance patterns.

Neuromuscular disorders may be autosomal dominant (passing from affected parent to child 50% of the time), autosomal recessive (passing from two unaffected, carrier parents to child 25% of the time), or X-linked (passing from an unaffected carrier mother to a child (almost always a son) 50% of the time).

  • For those diseases that are X-linked (such as Duchenne and Emery Dreifuss muscular dystrophies and some of the Charcot Marie Tooth disorders), pay particular attention to the extended maternal family (i.e., ask if the mother and maternal grandmother have brothers, and are there any concerns?).

Excerpts from Bright Futures Guidelines: Surveillance of Development Milestones and Physical Exam

Recommendations Relevant to Gross Motor Surveillance (accessed 2011 from

1 month:

  • Surveillance of Development: “is able to lift his head when on tummy”
  • Physical Exam: “Assess neurologic tone”

2 months:

  • Surveillance of Development: “is able to hold up head and begins to push up in prone position, has consistent head control in supported sitting position, shows symmetrical movements of head, arms, and legs, shows diminishing newborn reflexes”
  • Physical Exam: “Assess torticollis, neurologic tone, strength and symmetry of movements.”

4 months:

  • Surveillance of Development: “pushes chest to elbows, has good head control, demonstrates symmetrical movements of arms/legs, begins to roll and reach for objects”
  • Physical Exam: “Assess/Observe developmental hip dysplasia; neurologic tone, strength, and movement symmetry.”

6 months:

  • Surveillance of Development: “rolls over and sits, stands and bounces; moves to crawling from prone; rocks back and forth; is learning to rotate in sitting; will move from sitting to crawling”
  • Physical Exam: “Assess/Observe developmental hip dysplasia, neurologic tone, movement strength and symmetry.”

9 months:

  • Surveillance of Development: “expands motor skills”
  • Physical Exam: “Assess/Observe developmental hip dysplasia; neurologic tone, movement strength and symmetry. Elicit parachute reflex.”

12 months:

  • Surveillance of Development: “stands alone”
  • Physical Exam: “Observe gait.”

15 months

  • Surveillance of Development: “walks well, stoops, recovers, can step backwards”

18 months

  • Surveillance of Development: “walks up steps/runs”
  • Physical Exam: “Observe gait, hand control, arm/spine movement.”

24 months:

  • Surveillance of Development: “throws ball overhand; goes up and down stairs one step at a time, jumps up”
  • Physical Exam: “Observe running.”

2.5 year visit

  • Surveillance of Development: “jumps up and down in place, throws ball overhand”
  • Physical Exam: “Observe coordination.”

3 year visit

  • Surveillance of Development: “throws ball overhand, walks up stairs alternating feet”

4 year visit

  • Surveillance of Development: “hops on one foot, balances on one foot for 2 seconds”
  • Physical Exam: “Observe fine/gross motor skills.”

5 and 6 year visits

  • Surveillance of Development: “Balances on one foot, hops, and skips”
  • Physical Exam: “fine/gross motor skills, gait”