UMN and LMN Syndromes & Differential Diagnosis

Location of UMN lesion

Central nervous system cortex, brainstem, corticospinal tracts, spinal cord

Location of LMN lesion

Cranial nerve nuceli/nerves

Spinal cord: anterior horn cell, spinal roots

Peripheral nerve

Diagnosis/pathology of UMN lesion

Stroke, TBI, SCI

Diagnosis/pathology of LMN lesion

Polio, GBS

Peripheral nerve injury

Peripheral neuropathy

Radiculopathy

Tone UMN lesion

Increased: hypertonia

Velocity dependent

Tone LMN lesion

Decreased or absent: hypotonia, flaccidity

Not velocity dependent

Reflexes UMN lesion

Increased: hyperreflexia, clonus

Exaggerated cutaneous and autonomic reflexes, +Babinski

Reflexes LMN lesion

Decreased or absent: hyporeflexia

Cutaneous reflexes decreased or absent

Involuntary movements UMN lesion

Muscle spasms: flexor or extensor

Involuntary movements LMN lesion

With denervation: fasciculations

Strength UMN lesion

Weakness or paralysis: ipsilateral (stroke) or bilateral (SCI)

Corticospinal: contralateral if above decussation in medulla; ipsilateral if below

Distribution: never focal

Strength LMN lesion

Ipsilateral weakness or paralysis

Limited distribution: segmental or focal pattern, root-innervated pattern

Muscle bulk UMN lesion

Disuse atrophy: variable, widespread distribution, especially of antigravity muscles

Muscle bulk LMN lesion

Neurogenic atrophy: rapid, focal distribution, severe wasting

Voluntary movements UMN lesion

Impaired or absent dyssynergic patterns, obligatory mass synergies

Voluntary movements LMN lesion

Weak or absent if never interrupted

Diagnosis/pathology: Cerebral cortex and corticospinal tracts

Stroke

Diagnosis/pathology: Basal ganglia

Parkinson's disease

Diagnosis/pathology: Cerebellum

Tumor

Stroke

Diagnosis/pathology: Spinal cord

Trauma, tumor, vascular insult: complete, incomplete SCI

Sensation: Cerebral cortex and corticospinal tracts

Impaired or absent: depends on lesion location; contralateral sensory loss

Sensation: Basal ganglia

Not affected

Sensation: Cerebellum

Not affected

Sensation: Spinal cord

Impaired or absent below level of lesion

Tone: Cerebral cortex and corticospinal tracts

Hypertonia/spasticity velocity-dependent; clasp-knife

Initial flaccidity: cerebral shock

Tone: Basal ganglia

Lead pipe rigidity: increased, uniform resistance

Cogwheel rigidity: increased, ratchet-like resistance

Tone: Cerebellum

Normal or may be decreased

Tone: Spinal cord

Hypertonia/spasticity below the level of the lesion

Initial flaccidity: spinal shock

Reflexes: Cerebral cortex and corticospinal tracts

Hyperreflexia

Reflexes: Basal ganglia

Normal or may be decreased

Reflexes: Cerebellum

Normal or may be decreased

Reflexes: Spinal cord

Hyperreflexia

Strength: Cerebral cortex and corticospinal tracts

Contralateral weakness or paralysis: hemiplegia or hemiparesis

Disuse weakness in chronic stage

Strength: Basal ganglia

Disuse weakness in chronic stage

Strength: Cerebellum

Normal or weak: asthenia

Strength: Spinal cord

Impaired or absent below the level of the lesion: paraplegia or paraparesis; tetraplegia or tetraparesis

Muscle bulk: Cerebral cortex and corticospinal tracts

Normal during acute stage; disuse atrophy in chronic stage

Muscle bulk: Basal ganglia

Normal or disuse atrophy

Muscle bulk: Cerebellum

Normal

Muscle bulk: Spinal cord

Disuse atrophy

Involuntary movements: Cerebral cortex and corticospinal tracts

Spasms

Involuntary movements: Basal ganglia

Resting tremor

Involuntary movements: Cerebellum

None

Involuntary movements: Spinal cord

Spasms

Voluntary movements: Cerebral cortex and cortiospinal tract

Dyssynergic: abnormal timing, co-activation, fatiguability

Voluntary movements: Basal ganglia

Bradykinseia: slowness of movement

Akinesia: absence of movement

Voluntary movements: Cerebellum

Ataxia: intention tremor, dysdiadokinesia, dysmetria, dyssynergia nystagmus

Voluntary movements: Spinal cord

Above level of lesion: intact (normal)

Below level of lesion: impaired or absent

Postural control: Cerebral cortex and corticospinal tracts

Impaired or absent, depends on lesion location

Impaired balance

Postural control: Basal ganglia

Impaired: stooped (flexed)

Impaired balance

Postural control: Cerebellum

Impaired: truncal ataxia

Impaired balance

Postural control: Spinal cord

Impaired below level of lesion

Impaired balance

Gait: Cerebral cortex and corticospinal tract

Impaired: gait deficits due to abnormal weakness, synergies, spasticity, timing deficits

Gait: Basal ganglia

Impaired: shuffling, festinating gait

Gait: Cerebellum

Impaired: ataxic gait deficits, wide-based, unsteady

Gait: Spinal cord

Impaired or absent: depends on level of lesion

Dorsal (posterior) solum-medial lemniscal pathway

Important to coordinated movement

Sensations include: discriminative touch, stereognosis, tactile pressure, barognosis, graphesthesia, recognition of texture, kinesthesia, 2-point discrimination, proprioception, and vibration

Composed of large, myelinated, rapidly conducting fibers.

Ascend to medulla and then cross

Motor impairments that are manifestations of cerebellar pathology

Asthenia

Dysarthria

Dysdiadokinesia

Dysmetria

Dyssynergia

Asynergia

Gait ataxia

Hypotonia

Nystagmus

Rebound phenomenon

Tremor

Asthenia

Generalized muscle weakness

Dysarthria

Disorder of motor component of speech articulation

One word at a time quality

Slow, slurred, hesitant with prolonged syllables and inappropriate pauses. Grammar remains intact but melodic quality of speech is altered

Dysdiadokinesia

Impaired ability to perform rapid alternating movements

Movements are irregular and, with a rapid loss of range and rhythm especially as speed is increased

Dysmetria

Inability to control the distance, power, and speed of a muscular action

Dyssynergia (movement decomposition)

Movement performed in a sequence of component parts rather than as a single, smooth activity

Asynergia

Inability to move muscles together in a coordinated manner

Gait ataxia

Unsteady walking, wide base of support

Hypotonia

A decrease in muscle tone believed to be related to the disruption of afferent input from stretch receptors and/or lack of the cerebellums facilitatory efferent influence on the fusimotor system

Nystagmus

Rhythmic, quick, oscillatory, back and forth movement of the eyes. Typically apparent as the eyes move away from midline to fix on an object in either the medial or lateral field. Patient has difficulty holding the gaze on the object in peripheral field.

Rebound phenomenon

Inability to stop a motion quickly to avoid striking something

Tremor (cerebellum)

Involuntary oscillatory movement resulting from alternate contractions of opposing muscle groups

Intention armoe occurs during voluntary motion of a limb and tends to increase as the limb nears its intended goal or when speed is increased. Diminished or absent at rest.

Postural tremor may be evident by back-and-forth oscillatory movements of the body while patient maintains standing posture

Basal ganglia pathology

Akinesia

Athetosis

Bradykinesia

Chorea

Choreoathetosis

Dystonia

Hemiballismus

Hyperkinesis

Rigidity

Tremor

Akinesia

Inability to initiate movement

Athetosis

Slow, twisting, writhing movement, resembling a snake or worm

Bradykinesia

Slow movement: decreased arm swing, slow shuffling gait, difficulty initiating or changing direction of movement, lack of facial expression, or difficulty stopping a movement once it has begun

Chorea

Sudden, rapid, jerky, purposeless movement involving limbs, trunk, or face

Choreoathetosis

Movement disorder with features of both chorea and athetosis

Dystonia

A condition of abnormal muscle tone that causes the impairment of voluntary muscle movement

Hemiballisumus

Lesions of the Basal Ganglia

Unilateral chorea in which there are violent, forceful, flinging movements of the extremities on one side of the body, particularly involving the proximal musculature

Hyperkinesis

Excessive movement

Rigidity

Increase in muscle tone causing greater resistance to passive movement

Lead pipe and cogwheel

Tremor (basal ganglia)

Involuntary oscillatory movement resulting from alternate contractions of opposing muscle groups

Pill rolling: looks like a pill being rolled between thumb and first two fingers