La pérdida auditiva afecta a la vía aérea.

Because Spanish often uses the definite article with general concepts, conditions, and abstract nouns more than English does.

Here, la pérdida auditiva means hearing loss as a condition or phenomenon. In natural Spanish, leaving out the article in a full sentence would usually sound wrong:

• La pérdida auditiva afecta... = normal
• Pérdida auditiva afecta... = sounds like a headline, label, or note

So even though English often says just hearing loss, Spanish normally says la pérdida auditiva in a complete sentence.

Because auditiva is an adjective agreeing with pérdida, and pérdida is feminine singular.

Agreement in Spanish means the adjective must match the noun:

• la pérdida auditiva
• el problema auditivo
• los trastornos auditivos

So auditiva is feminine singular because pérdida is feminine singular.

Yes, often.

Both are correct and both can mean hearing loss, but they feel slightly different:

• pérdida auditiva = more technical, medical, clinical
• pérdida de audición = more transparent and everyday

So in a medical text, pérdida auditiva is very common. In everyday speech, many people might prefer pérdida de audición because it is easier to understand immediately.

With afectar, Spanish very often uses a before the person, organ, system, or thing that is affected.

So these are all natural:

• La enfermedad afecta al corazón
• La crisis afecta a muchas familias
• La inflamación afecta a la vía aérea

You may also sometimes see afectar used without a, especially depending on region, style, or what follows. But afecta a la vía aérea is very normal and natural Spanish.

So the a here is not just random; it introduces the affected target.

Because al is only the contraction of a + el.

• a + el = al
• a + la = a la

Since vía is feminine, you get:

• a la vía aérea

Compare:

• afecta al oído
• afecta a la vía aérea

Yes, both singular and plural are possible, depending on what exactly you mean.

• la vía aérea often refers to the airway as one functional structure or system
• las vías aéreas often refers to the airways, meaning the passages more generally

Medical Spanish uses both. The singular in your sentence is not wrong; it just presents the airway as a single entity.

Each accent mark is there for a reason:

• pérdida: the stress is on the first syllable, and it is an esdrújula word. All esdrújulas take a written accent.
• vía: the accent on í shows that í and a are pronounced in separate syllables: ví-a
• aérea: the stress falls on é: a-É-re-a, so the accent shows the correct stress

So the accents are helping you pronounce the words correctly, not just decorating them.

A good stress guide is:

la PÉR-di-da au-di-TI-va a-FEC-ta a la VÍ-a a-É-re-a

A few useful pronunciation notes:

• v and b sound the same in Spanish
• r in aérea is a single tap, not a long English r
• vía has two syllables: ví-a
• aérea has four syllables: a-é-re-a

A rough Spain pronunciation in syllables would be:

la / pér-di-da / au-di-ti-va / a-fec-ta / a / la / ví-a / a-é-re-a

This is a very useful distinction:

• pérdida = loss
  A noun

• perdida = lost
  Feminine adjective or past participle

So:

• la pérdida auditiva = hearing loss
• la maleta perdida = the lost suitcase

The accent changes both the pronunciation and the meaning.

The original order is the most neutral and standard:

La pérdida auditiva afecta a la vía aérea.

Spanish can change word order for emphasis, but that makes the sentence more marked:

• A la vía aérea la afecta la pérdida auditiva

That version is grammatically possible, but it sounds more emphatic or stylistically marked. For normal explanatory prose, the original sentence is the best choice.

Yes. Vía aérea is a common medical expression meaning airway.

It works as a noun phrase made of:

• vía = way, route, passage
• aérea = air-related, aerial

But together, vía aérea is best learned as one medical unit, because it functions like a standard term rather than a freely invented phrase.