Maximum Expiratory Pressure (MEP) will be measured in sitting position and optionally in lying position.

The FSS is a unidimensional scale which focuses on the physical aspects of fatigue. It is a self-reported questionnaire developed to measure the impact of disabling fatigue on daily functioning. It covers several areas including physical, social, and cognitive effects. The FSS is a patient-reported outcome composed of 9-items with scores ranging from 1 = "strongly disagree" to 7 = "strongly agree".

The purpose of those tests is to measure the maximum isometric strength of the hand and forearm muscles when doing a grasping or a pinching action. The equipment required for the grip and the pinch tests is a calibrate dynamometer. The subject should be strongly encouraged to give a maximum effort. We record three trials for each hand, alternating hands with at least 30 seconds recovery between each effort. We keep the best result.

The r9HPT is a modification of the 9-Hole Peg test (9HPT) targeting endurance instead of motor function. The 9HPT is a brief, standardized, quantitative test of upper extremity function.

In r9HPT, participants performed 5 consecutive rounds of the 9HPT, without break, using the same and preferred hand. We will look at the change (ratio) in score between the last trial and the first trial, an increase in time needed to perform the test in consecutive rounds indicating the apparition of the muscle fatigability.

The RHS consisted of 36 items for very weak SMA 2 through to very strong SMA 3. With regards scoring, 33 items were graded on an ordinal scale of 0, 1, 2 (where 0 denotes the least level of ability/function progressing to the highest level of ability to achieve a score of 2), the remaining 3 items were scored 0, 1 (where 0 is unable and 1 was able to achieve). The maximum achievable score is 69.

The Iowa Oral Performance Instrument (IOPI) is a means to quantify lip, tongue, and buccal strength using a validated tool with published ranges for normative data for lingual measurements

The RULM is a validated measure and used only for patients with SMA that evaluates shoulder, wrist, and hand functions. It takes approximately 15 minutes to administer and requires a toolkit that is used to have the patient repeat specific tasks (eg, picking up a coin, bringing hand to mouth) with both arms. RULM is a scale of 19 scorable items; each item is scored from 0 to 2:

• 0=Unable
• 1=Able, with modification
• 2=Able, no difficulty The maximum score is 37 and the patients are scored on both upper limbs.

MUNIX is a neurophysiologic test which provide an index of functioning lower motor neurons in a muscle. MUNIX total score is calculated by adding the individual values of the 6 tested muscles (abductor pollicis brevis, abductor digiti minimi, first dorsal interosseous, deltoid, tibialis anterior and trapezius).

MUSIX is a neurophysiologic tests which provide an index of functioning lower motor neurons in a muscle. MUSIX is calculated by dividing MUNIX by the Compound Motor Action Potential (CMAP) amplitude, measured in 6 tested muscles (abductor pollicis brevis, abductor digiti minimi, first dorsal interosseous, deltoid, tibialis anterior and trapezius).

Health Status will be assessed using the question quality of Life in genetic Neuromuscular Disease (QoL-gNMD), specifically designed for patients with a slowly-progressive neuromuscular disease with genetic predominant muscular damage. The QoL-gNMD is splitted in 3 domains: "Impact of Physical Symptoms" (score from 0 to 19), "Self-perception" (score from 0 to 24) and "Activities and Social Participation" (score from 0 to 27).