This purpose of this study is to determine if tongue strength and tongue ultrasound measurements differentiates patients with untreated late-onset Pompe Disease (LOPD) from patients with acquires/hereditary myopathies or neuropathies. It is hypothesized that abnormalities in tongue function and structure in patients with LOPD may be useful in discriminating this condition from others that have similar presentations.

Inclusion Criteria:

• age ≥ 12 years
• confirmed diagnosis of LOPD and naïve to enzyme-replacement therapy (ERT)
• acquired/hereditary myopathy (e.g., dermatomyositis, polymyositis, inclusion body myositis, limb-girdle muscular dystrophy, distal myopathy, myotonic muscular dystrophy, and other myopathy)
• neuropathy (e.g., peripheral neuropathy, cranial neuropathy, autonomic neuropathy, focal neuropathy)

Exclusion Criteria:

• current use, history within the past two years of use, or eligible but declined use of Lumizyme® enzyme replacement therapy (applicable to LOPD group)
• history of stroke, Parkinson's disease, oculopharyngeal muscular dystrophy, head and neck cancer or radiation treatment to head/neck, or other conditions that commonly affect lingual strength
• inability to follow directions for study participation

Prospective participants must have a confirmed diagnosis of late-onset Pompe Disease, acquired/hereditary myopathy, or neuropathy.