Lecture Notes on Cerebellum, DCML, and Vestibular Systems

Flashcards about cerebellum, DCML, and vestibular systems

What is the primary function of the cerebellum?

Primary function of cerebellum is regulation of movement, postural control, and muscle tone

What does the vermis control?

Controls the trunk and central regions of the body and assists in balance and posture

What are the functions of the cerebellum?

Regulation of motor movements, coordination of voluntary movements, posture, balance, coordination, and speech

How does the cerebellum function?

Functions as a comparator and error correcting mechanism

What provides peripheral feedback during a motor response?

Muscle spindles, Golgi tendon organs, joint and cutaneous receptors, the vestibular apparatus, and the eyes and ears

What does feedback provide input regarding?

Feedback provides continual input regarding posture and balance, as well as position, rate, rhythm, and force of slow movements of peripheral body segments

What is the cerebellum important for?

Important for making postural adjustments in order to maintain balance

What is one major function of the cerebellum?

Coordinates the timing and force of different muscle groups to produce fluid limb or body movements

What is the cerebellum important for in regards to learning?

Important for motor learning

Asthenia

Abnormal physical weakness or lack of energy

Asynergia

Loss of ability to associate muscles together for complex movement

Delayed Reaction Time

Increased time required to initiate voluntary movement

Dysarthria

Disorder of the motor component of speech articulation

Dysdiadochokinesia

Impaired ability to perform rapid alternating movement

Dysmetria

Inability to judge the distance of range of movement

Dyssynergia

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

Gait Disorders

Ataxic pattern; broad base of support; postural instability; high-guard position of UE’s

Hypotonia

Decreased in muscle tone

Hypermetria

Overestimation of distance or range needed to accomplish a movement

Hypometria

Underestimation of distance or range needed to accomplish a movement

Nystagmus

Rhythmic, quick, oscillatory, back-and-forth movements of the eyes

Rebound Phenomenon

Loss of the check reflex or check factor, which functions to halt forceful active movements when resistance is eliminated

Tremor

Involuntary oscillatory movement resulting from alternate contraction of opposing muscle groups

Intention (kinetic) tremor

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 (static) tremor

Evident by back-and-forth oscillatory movements of the body while the patient maintains a standing posture

Titubation

Rhythmic oscillations of the head; axial involvement of the trunk

Where are the Basal Ganglia located?

Located at the base of the cerebral cortex

What are the functions of the Basal Ganglia?

Initiation and regulation of gross intentional movement, planning and execution of complex motor responses, facilitation of desired motor responses while selectively inhibiting others

Akinesia

Inability to initiate movement; associated with fixed posture

Athetosis

Slow, involuntary, writhing, twisting, “wormlike” movements; frequently greater involvement in distal UE’s

Bradykinesia

Decreased amplitude and velocity of voluntary movement

Chorea

Involuntary, rapid, irregular, jerky, movements involving multiple joints; most apparent in UEs

Choreoathetosis

Movement disorder with features of both chorea and athetosis

Dystonia (dystonic movements)

Sustained involuntary contractions of agonist and antagonist muscle

Hemiballismus

Large-amplitude sudden, violent, flailing motions of the arm and leg of one side of the body

Hyperkinesis

Abnormally increased muscle activity or movement

Hypokinesis

Decreased motor response especially to specific stimulus

Rigidity

Increase in muscle tone causing greater resistance to passive movement; greater in flexor muscles

Lead-Pipe rigidity

Uniform, constant resistance as limb is moved

Cogwheel rigidity

Series of brief relaxations or “catches” as limb is passively moved

Tremor (resting)

Involuntary, rhythmic, oscillatory movement observed at rest

Why is Dorsal Column- Medial Lemniscal Pathway important?

Important to coordinated movement, as it is responsible for the afferent transmission of discriminative sensations

What sensations does Dorsal Column- Medial Lemniscal Pathway convey?

Discriminative touch, stereognosis, tactile pressure, barognosis, graphesthesia, recognition of texture, kinesthesia, two-point discrimination, proprioception, and vibration

What do Lesions of the DCML result in?

Coordination and equilibrium impairments related to the patient’s lack of joint position sense and awareness of movement, and impaired localized touch sensation

Disturbances of gait

Present with a widened-base with swaying, uneven step length and excessive lateral displacement

Dysmetria

Impaired ability to judge and required distance or range of movement and may be noted in both the upper extremity and lower extremity

What can happen when vision is occluded or when the patient’s eyes are closed?

Coordination and/or balance problems will be exaggerated when vision is occluded or when the patient’s eyes are closed

Positive Romberg Sign

The inability to maintain standing balance with the feet together when the eyes are closed

What sensory systems provide the CNS with important information about postural control and balance?

Vision, somatosensory, and vestibular

What is the Principal brain area involved in motor function?

Motor cortex; comprises cortical (Brodmann) areas 4 and 6, located in a demarcated area of the frontal lobe called the precentral gyrus

What is Brodmann area 4?

The primary motor cortex

What is Brodmann area 6?

Just anterior to area 4 and is subdivided into the superiorly placed supplementary motor area (SMA) and the inferiorly positioned premotor area (PMA)

What is the descending Motor Pathway?

Corticospinal (pyramidal) tract that transmits signals from the motor cortex directly to the spinal cord