What is the medical term for a patient who stutters or hesitates when attempting to turn while walking?

Freezing of Gait (FOG)

The medical term for stuttering or hesitation when attempting to turn while walking is "freezing of gait" (FOG), a disabling parkinsonian phenomenon characterized by brief episodes of inability to produce effective forward stepping, most commonly occurring during turns, gait initiation, or when approaching a destination. 1, 2, 3

Clinical Characteristics

FOG manifests as sudden attacks of immobility with the following specific features:

• Sudden arrest of stepping during walking, particularly when turning or approaching destinations 1, 2
• Extremely short, rapid steps with trembling of the legs (hastening phenomenon at 4-5 Hz frequency) 2, 4
• Episodes occurring in narrow spaces or stressful situations 2, 4
• Increased stride-to-stride variability between freezing episodes 2

Underlying Pathophysiology

The neuroanatomical substrate involves:

• Dysfunction in frontal cortical regions, basal ganglia, and midbrain locomotor region 3
• Abnormalities in dopamine and norepinephrine neurotransmission in critical motor control areas including frontal lobe, basal ganglia, locus coeruleus, and spinal cord 1
• Impaired fronto-basal ganglia projections, as hastening phenomenon occurs in both Parkinson's disease and striatal lesions 2, 4

Disease Stage and Context

FOG typically appears in advanced Parkinson's disease but can occur in early stages:

• Most commonly observed in patients with long disease duration and advanced stage 1, 4
• Strongly associated with motor fluctuations, occurring predominantly in "off" states but also in "on" states 2, 4
• Dual tasking (cognitive load) significantly aggravates FOG 2, 4

Distinguishing from Other Parkinsonian Features

FOG is a distinct clinical feature separate from general akinesia or bradykinesia:

• FOG represents a unique phenomenon independent of general slowness of movement (bradykinesia) 1
• Unlike continuous bradykinesia, FOG occurs as episodic, sudden attacks 1, 3
• FOG is specifically triggered by environmental or cognitive factors (turns, narrow spaces, destinations), whereas bradykinesia is constant 2, 4

Critical Diagnostic Pitfall

Do not confuse FOG with other atypical parkinsonian syndromes that present with gait disturbance and falls:

• Progressive supranuclear palsy (PSP) presents with lurching gait and axial dystonia manifested as unexplained falls, but lacks the episodic freezing pattern 5
• PSP patients fall early in disease course without the characteristic "stuttering" pattern of FOG 5
• Cerebellar dysfunction causes dysmetria (impaired distance measurement in movements) rather than episodic freezing 5

Therapeutic Response Patterns

FOG responds variably to interventions:

• Visual or auditory cues often resolve FOG episodes acutely 2, 4
• If FOG occurs predominantly in "off" state, increasing dopaminergic therapy can be effective 2
• For "on" freezing, dopaminergic dose manipulation may be attempted but risks worsening overall parkinsonism 2
• Deep brain stimulation of the subthalamic nucleus often alleviates FOG in the "off" state 2
• FOG is generally resistant to pharmacological therapy, though some patients improve with levodopa dose adjustment (either reduction or increase) 1