**4. Diagnosis**

Diagnosis of SMA is suspected on the bases of the clinical picture, muscle biopsy and electromyography. Genetic testing is the only definitive diagnostic test for patients with SMA. With the use of genetic testing, the role of EMG and muscle biopsy in confirming the diagnosis of SMA is limited. They can be used for the diagnosis of patients with SMA who present without homozygous deletion of the SMN gene.32 Genetic testing of SMA shows a deletion of the SMN gene on the fifth chromosome. EMG findings usually show a pattern of denervation including fibrillation potentials, positive sharp waves, and large amplitude, short duration actions potentials. Sensory nerve conduction velocities are normal with no marked decrease of motor nerve conduction velocities. Muscle biopsy provides evidence of muscle denervation with groups of small atrophic fibers with large hypertrophic fibers.

Spinal Muscular Atrophy 225

widely method to assess muscle strength in clinical practice. It is a reasonably easy and inexpensive in measuring muscle strength in patients with SMA, but it does not allow grading small changes in muscle strength. A handheld dynamometer can be used to quantify muscle strength. Using a dynamometer is easy and comfortable and allows for

Pulmonary function tests are parts of the regular assessment in patients with SMA to monitor changes in respiratory status. Routine assessment of respiratory function includes complete pulmonary function tests, including sprirometery, lung volumes, and respiratory muscle function tests.30 Assessments of cough effectiveness and breathing pattern are important for the non-ambulatory patients or patients who are too weak or too young to

No disease-specific gait test or measure exists for patients with SMA. Description of gait deviations and safety and stability during walking should be included as part of routine gait analysis. The 10-Meter Walk test can be used to measure gait speed. The Six Minute Walk

Examination of functional status including examination of functional mobility skills and activities of daily living is an important consideration. Several clinical outcome measures can be used to measure functional outcomes in patients with SMA including generic measures and disease-specific measures. Generic outcome measures commonly used in patients with SMA include the Gross Motor Function Measure, the Test of Infant Motor Performance, the Alberta Infant Motor Scale, the Wee Functional Independence Measure, the Motor Function Measure, and the EgenKlassifikation Scale. Disease-specific outcome measures include the Hammersmith Functional Motor Scale, the Modified Hammersmith Functional Motor Scale, the Expanded Hammersmith Functional Motor Scale, the Children's Hospital of Philadelphia Test of Strength in spinal muscular atrophy, the Infant Test for Neuromuscular Disease, and the Spinal Muscular Atrophy Functional Rating Scale. Selection of the outcome measures to be used is based on age of the patient, patient's functional level, aspects of function being measured, ease of administration, and burden imposed on the patient. The Pediatric Quality of Life Inventory (PedsQL) instrument can be used to measure

No specific therapy is currently available for SMA. Treatment is usually supportive, and may include physical therapy, occupational therapy, nutrition, orthotic management, and possibly surgical intervention. Appropriate recommendations are made on the basis of each patient's presentation and functional level.15 The most important goal in the management of the patients is to achieve maximal independent living with maximized mobility, and to

Test or the Two Minute Walk Test can be used to measure endurance during gait.

measuring small changes in strength over a continuous range.19

**6.6 Measurement of functional status and quality of life** 

**6.4 Respiratory function** 

**6.5 Gait** 

quality of life.

**7. Management** 

perform pulmonary function testing.30
