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Difficulty: HardPhysiological Effects of Alcohol on Driving Performance

Alcohol consumption impairs smooth pursuit eye movements—the ability of extraocular muscles to track moving objects continuously across a visual field—causing a driver's eyes to make involuntary, jerky movements when scanning passing traffic, even at low Blood Alcohol Concentration (BAC) levels well below 0.08%.

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Answer

True. Alcohol impairs fine oculomotor muscle control and smooth pursuit eye movements at low Blood Alcohol Concentration (BAC) levels well below the 0.08% legal limit, leading to involuntary jerky eye tracking when monitoring moving objects.
The statement is true because alcohol impairs the brainstem pathways responsible for smooth pursuit eye movements. This causes the eyes to movement-lag and jump involuntarily when following moving targets, an effect that manifests at low Blood Alcohol Concentration levels (0.03%–0.05%) well below the legal driving threshold.

Step-by-Step Solution

1
Analyze how alcohol depresses central nervous system functions related to ocular muscle control.
Alcohol reduces the brain's capacity to execute smooth pursuit eye movements, which require continuous, precise neural feedback to extraocular muscles.
Fine neural pathways and delicate muscle groups are among the earliest physiological systems disrupted by alcohol intake.
2
Evaluate the threshold BAC levels at which visual tracking impairment begins.
Loss of smooth pursuit and onset of saccadic jerking (nystagmus) occur at low BAC levels (around 0.03% to 0.05%), well under the standard legal threshold of 0.08%.
Legal limits reflect broad behavioral impairment standards, but specific physiological sensory and ocular degradation occurs at substantially lower concentrations.
3
Determine the truth value of the stem statement.
The statement accurately describes the physiological mechanism and low BAC threshold of alcohol-induced smooth pursuit impairment.
The described physiological degradation is scientifically validated and recognized in driver safety assessment standards.

Key Concept

Physiological Impact of Alcohol on Oculomotor Smooth Pursuit
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Topics

Physiological Effects of Alcohol on Driving Performance

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