Abstract: The present disclosure provides compounds represented by Formula I: I, and the pharmaceutically acceptable salts and solvates thereof, wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, and R13 are as defined as set forth in the specification, and the deuterium enrichment of any one or more of R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, and R13 is about 15% or more. The present disclosure also provides compounds having Formula I for use to treat or delay the progression of a lysosomal storage disorder or a neurodegenerative disease in a subject, provide neuroprotection in a subject having a lysosomal disorder, treat or prevent a migraine, and the symptoms associated therewith, in a subject, or improve mobility and/or cognitive function in a subject.

Abstract: A first aspect of the invention relates to betahistine, or a pharmaceutically acceptable salt thereof, and a monoamine oxidase inhibitor, for use in the treatment or prevention of one or more symptoms of vertigo in a subject. A second aspect of the invention relates to a method of treating or preventing one or more symptoms of vertigo in a subject, said method comprising administering to the subject (i) betahistine, or a pharmaceutically acceptable salt thereof, and (ii) a monoamine oxidase inhibitor.

Abstract: The present disclosure is directed to acetyl-leucine or a pharmaceutically acceptable salt thereof for use in improving cognitive function, mobility, or cognitive function and mobility in a subject, for example, in an elderly subject.

Abstract: A first aspect of the invention relates to betahistine, or a pharmaceutically acceptable salt thereof, and a monoamine oxidase inhibitor, for use in the treatment or prevention of one or more symptoms of vertigo in a subject. A second aspect of the invention relates to a method of treating or preventing one or more symptoms of vertigo in a subject, said method comprising administering to the subject (i) betahistine, or a pharmaceutically acceptable salt thereof, and (ii) a monoamine oxidase inhibitor.

Abstract: The present disclosure provides methods of treating ataxia in a subject in need thereof by administering a combination of acetyl-leucine and 4-aminopyridine or a combination of acetyl-leucine and acetazolamide to the subject.

Abstract: The present disclosure provides methods of treating, preventing, or delaying the onset of a late-onset neurodegenerative disease, e.g., Niemann-Pick type C, or a symptom thereof in a subject in need thereof, comprising administering a therapeutically effective amount of acetyl-leucine to the subject, wherein the subject is heterozygous NPC1 gene mutation carrier.

Abstract: A first aspect of the invention relates to leucine, acetyl-leucine, or a pharmaceutically acceptable salt thereof, for use in treating or preventing a migraine, or one or more symptoms associated therewith. A second aspect of the invention relates to a method of treating or preventing a migraine, or one or more symptoms associated therewith, in a subject, said method comprising administering to the subject a therapeutically or prophylactically effective amount of leucine, acetyl-leucine, or a pharmaceutically acceptable salt thereof.

Abstract: The present disclosure provides methods of treating diseases, disorders, conditions, or syndromes, e.g., traumatic brain injury, in a patient in need thereof by administering a therapeutically effective amount of DL-leucine, or a pharmaceutically acceptable salt thereof, L-leucine, or a pharmaceutically acceptable salt thereof, D-leucine, or a pharmaceutically acceptable salt thereof, L-leucine ethyl ester, or a pharmaceutically acceptable salt thereof, acetyl-DL-leucine, or a pharmaceutically acceptable salt thereof, acetyl-D-leucine, or a pharmaceutically acceptable salt thereof, or acetyl-L-leucine, or a pharmaceutically acceptable salt thereof.

Abstract: A first aspect of the invention relates to betahistine, or a pharmaceutically acceptable salt thereof, and a monoamine oxidase inhibitor, for use in the treatment or prevention of one or more symptoms of vertigo in a subject. A second aspect of the invention relates to a method of treating or preventing one or more symptoms of vertigo in a subject, said method comprising administering to the subject (i) betahistine, or a pharmaceutically acceptable salt thereof, and (ii) a monoamine oxidase inhibitor.

Abstract: A first aspect of the invention relates to betahistine, or a pharmaceutically acceptable salt thereof, and a monoamine oxidase inhibitor, for use in the treatment or prevention of one or more symptoms of vertigo in a subject. A second aspect of the invention relates to a method of treating or preventing one or more symptoms of vertigo in a subject, said method comprising administering to the subject (i) betahistine, or a pharmaceutically acceptable salt thereof, and (ii) a monoamine oxidase inhibitor.

Abstract: The present disclosure is directed to acetyl-leucine or a pharmaceutically acceptable salt thereof for use in improving cognitive function, mobility, or cognitive function and mobility in a subject, for example, in an elderly subject.

Abstract: The present disclosure provides for treating neurodegenerative diseases and lysosomal storage disorders comprising administering leucine, or a pharmaceutically acceptable salt thereof for direct delivery in a subject in need thereof. The disclosure further provides for leucine, or a pharmaceutically acceptable salt thereof for direct delivery in a subject in need thereof, for example, in an elderly subject, to improve cognitive function, mobility, or cognitive function and mobility.