Like subordinate clauses, phrases function within sentences as adjectives, as adverbs, or as nouns. They cannot stand alone. Fragmented phrases are often prepositional or verbal phrases; sometimes they are appositives, words or word groups that rename nouns or pronouns.

Often a fragmented phrase may simply be pulled into a nearby sentence.

The word group beginning with Examining is a verbal phrase.

A neurodegenerative disease is an appositive renaming the noun ALS.

If a fragmented phrase cannot be pulled into a nearby sentence effectively, turn the phrase into a sentence. You may need to add a subject, a verb, or both.

The revision turns the fragmented phrase into a sentence by adding a subject and a verb.