Final answer:
The early indicator of deterioration in a client's condition with signs of increased intracranial pressure (ICP) is a decrease in the level of consciousness (LOC). A widening pulse pressure and decrease in the pulse rate reflect later stages of increased ICP, while a dilated, fixed pupil is a sign of very severe brain injury.
Step-by-step explanation:
A client displaying signs of increased intracranial pressure (ICP) may show several indicators of deterioration in their condition. Among the options given, decrease in level of consciousness (LOC) is an early indicator of deterioration. Changes in LOC may manifest as drowsiness, confusion, or lethargy, signaling that the brain may be starting to suffer from the effects of the increased pressure.
A widening pulse pressure (difference between systolic and diastolic blood pressures) and decrease in the pulse rate can occur as part of Cushing's triad, which indicates an elevated ICP, but these are generally seen in the later stages. A dilated, fixed pupil is also a late sign and, when present, typically indicates herniation and very severe brain injury.