Interrupted sleep, leading to poor rest quality.

• A. Fragmented Sleep
• B. Delayed Onset of Sleep
• C. NREM Sleep
• D. REM

Answer: (A)

Fragmented sleep occurs when sleep is repeatedly interrupted by awakenings or arousals, resulting in poor rest quality. Even if total sleep time seems adequate, frequent awakenings disrupt the continuity of sleep cycles, preventing progression into deeper, restorative stages of NREM and REM. This fragmentation leaves the sleeper returning to wakefulness frequently, which reduces sleep efficiency and leaves daytime fatigue, cognitive sluggishness, and mood changes.

Delayed onset of sleep describes trouble falling asleep initially, not interruptions after sleep begins, so it doesn’t capture the issue of interrupted sleep. NREM and REM are stages within the sleep cycle, not patterns of interruption; they can be disrupted by fragmentation, but they don’t define the pattern of wake bouts themselves. In older adults, lighter, more easily disrupted sleep is common, making fragmentation a typical way to describe the resulting poor rest quality.