The impaired memory for events that occurred before the onset of amnesia is called:

Retrograde amnesia is the impaired memory for events that occurred before the onset of amnesia.

The phonemic loop refers to verbal rehearsal in working memory, not a memory-loss condition.

Post-traumatic amnesia is the confused, memory-poor state immediately after a head injury, not specifically loss of pre-onset events.

The visuospatial sketchpad is a working-memory component for visual and spatial data, unrelated to amnesia types.

Retrograde loss usually spares older, well-consolidated memories more than recent ones, following Ribot's law.

Anterograde amnesia is its counterpart, affecting new learning after onset.