Spinal muscular atrophy (SMA) is a disorder that leads to muscle weakness. People with this condition have problems with motor skills — abilities relating to how a person controls their muscles and moves their body. To measure SMA symptoms and determine how severe the disease is, health care providers often test a person’s motor skills. One possible test that can provide information about SMA progression is the Hammersmith Infant Neurological Examination — Part 2 (HINE-2) motor test.
As a child grows, they will often achieve physical milestones. Milestones fall into several different categories. SMA often affects motor milestones, which include skills like holding the head up, grabbing objects, or sitting up.
HINE-2 is a test that helps determine whether infants or young children are able to reach motor milestones. This assessment tool measures how well children are able to perform different activities that require using muscles. HINE-2 is not only used for cases of pediatric SMA, though. Doctors may also use this test to analyze motor function in children with other neuromuscular conditions, such as cerebral palsy.
The full Hammersmith Infant Neurological Exam contains three sections. Section 1 tests how well the nerves work. It analyzes how active the nerves are by measuring a person’s movements and reflexes. Section 3 focuses on behavior, including a person’s emotional state and whether they are conscious.
Section 2 of HINE tests motor skills. When this section is used alone as a clinical test, without sections 1 and 3, it is called HINE-2.
Doctors may use other motor function assessments instead of or in addition to HINE-2 to test motor function. These include the:
Each of these tests measures different muscle-related abilities and functions. Doctors choose which test to use based on several factors, including how old the person with SMA is, which SMA type they have, and whether the person is able to sit or walk. HINE is designed for very young children between 2 months and 24 months of age who cannot sit up.
This test helps doctors understand how well a child with SMA can carry out normal daily activities. This can provide clues about which types of therapies or assistive devices may be useful for improving quality of life.
HINE-2 is also useful for determining how a person’s motor function changes over time. Doctors can measure a person’s baseline function — how well a child can complete motor skills when first diagnosed or before treatment. Then, motor function can be measured again during multiple follow-up visits. This helps doctors understand whether SMA is progressing. If doctors see that an infant is losing motor skills, this may be a sign that a different treatment plan is needed.
The HINE-2 test is often used in SMA clinical trials. It has helped researchers both understand how SMA typically progresses and determine which developmental milestones can be reached by people with different SMA types.
HINE-2 has also been used in clinical trials for new SMA therapies. This test helps researchers see whether a particular treatment helps improve motor skills for people with SMA. For example, researchers used HINE-2 to measure whether Spinraza (nusinersen) was an effective treatment for SMA. This clinical study found that infants with SMA were better able to reach motor milestones after using this therapy.
In general, doctors recommend that children with SMA undergo tests to measure motor function every six months. In some cases, a doctor may recommend a different testing schedule based on a child’s individual needs. HINE-2 is conducted by a doctor or physical therapist.
HINE-2 analyzes eight different motor skills:
During the HINE-2 test, the health care professional measures each of these motor skills and assigns the skill a number. Each skill may receive a maximum of 3, 4, or 5 points. The higher the number, the more function a child has within that area. A score of 0 means that the child lacks that particular motor skill. A low score means that the child has some level of function in that area. A high score indicates that the child is able to fully complete the motor skill.
All of the scores for each motor skill are added up to provide one total score. The maximum score a child can get on HINE-2 is 26. A child’s score depends on their age, level of development, and how severe their SMA is.
On mySMAteam, the social network for people with spinal muscular atrophy and their loved ones, more than 1,200 members come together to ask questions, give advice, and share their stories with others who understand life with SMA.
Is your child living with SMA? Has your child taken the HINE-2 motor test? Share your experiences in the comments below, or start a conversation by posting on mySMAteam.
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