Upper Extremity Function Assessment Quiz

Neural Contributions to Reach, Grasp, and Manipulation

• The course, DPT 425 Functional Neuroscience, covers the neural contributions to upper extremity (UE) functions, including reach, grasp, and manipulation.
• The primary resource for the information is the Shumway-Cook and Woollacott Motor Control text, Chapter 17.
• Upper-extremity (UE) function is fundamental to fine and gross motor skills and plays a key role in retraining motor control.
• Contextual factors (environment and individual) influence upper-extremity function significantly.
• UE function is integrated into daily activities such as self-care, work, and household tasks.

International Classification of Function (ICF)

• The ICF framework categorizes health conditions, body structure and function, activities, and participation.
• Body structure and function encompass neuromusculoskeletal and movement-related functions, including control of voluntary movements, visually directed movements, and eye-hand coordination.
• Activities refer to mobility (carrying, moving, handling objects), and tasks like self-care and activities of daily living.
• Participation involves activities in real-world situations

Sensorimotor Processing for Eye-Head-and-Hand Coordination

• Individual constraints, task type, and environmental constraints influence sensorimotor processing.
• The goal is to understand how an individual's CNS controls upper-extremity (UE) movements.

What is Going on in the Brain?

• Visual cortex, posterior parietal association area, somatosensory cortex, prefrontal area, premotor cortex, primary motor cortex, basal ganglia, and cerebellum play roles in sensory and motor processing.
• Spinal cord pathways (e.g., dorsal column/medial lemniscus) and sensory receptors (e.g., fingers and hand) support sensory processing.
• Motor neurons activate hand and forearm muscles, transmitting motor commands from the CNS.

Hedmann's Model for Movement Observation Analysis

• The model describes the stages of movement observation and analysis to evaluate motor performance.
• The model categorizes factors in determining the outcome of a movement.
• Includes segments for initial conditions, preparation, initiation, execution, and termination.

Motor Control Principles (SC&W PP 466)

• Motor control involves feedforward (anticipatory) and feedback (reactive) control.
• Motor program theory is discussed.
• Visual system plays a key role in anticipatory control, while Somatosensation is heavily involved in feedback control.
• Locating a target and reaching/grasping kinematics are significant components of movement control.

Feedforward versus Feedback Control of Movement

• Efficient reaching involves both feedforward and feedback processes.
• Feedforward (anticipatory) control uses prior experiences to predict sensory consequences.
• Feedback control uses sensory input to compare actual movement to a reference signal.

Motor Control Diagrams

• Feedforward control involves the feedforward controller that has memory and an anticipatory command. Disturbances happen at the same time.
• Feedback control receives the signal from the comparator, where input processing amplifies and filters the feedback.

Locating a Target (Eye-Head-Trunk Coordination)

• Vision guides hand movements, particularly in locating objects in far visual fields.
• Eye and hand movements interact with and influence each other.
• Proprioceptive signals from eye muscles contribute to locating targets in extrapersonal space.

Reach and Grasp Kinematics

• Adapting reach is crucial for upper extremity function.
• Task constraints and goals influence the reaching phase.
• Velocity profiles of arm movements vary based on task goals (pointing vs. grasping).

Neural Control of Reach and Grasp

• The brain regions involved in neural control of reach and grasp are detailed.
• Key areas like the Frontal, Limbic, and Motor Association cortices are involved.

Association Cortices - Perceptions and Planning

• Association cortices in the frontal, parietal, and temporal lobes are crucial for integrating movement with perception, including awareness and understanding of limbs in space and their location.
• They are essential for planning movement and relating movements to the extrapersonal space around the body.

Sensory System

• The sensory system helps understand surroundings and spatial awareness.
• Sensory information (body position mapping using somatosensory information) is essential for movement planning and performing accurate movements.
• Sensory feedback is essential to adjust the motor plan during movement, refining and correcting errors.

Visual Processing Pathways (Where and What Streams)

• Visual information travels through serial and parallel pathways (Where and What streams).
• Location in space and movement utilize the dorsal pathway to the parietal cortex.
• Shape, form, and object recognition utilize the ventral pathway to the inferior temporal cortex.

Clinical Implications

• Clinicians should assess perceptual and action components of visual-guided reaching.
• Different neurological components are involved, and impairment might affect specific neural locations.
• Understanding the crucial features of objects for grasping is vital for successful manipulation.

Posterior Association Areas

• The posterior parietal area mediates spatial cognition and attention to one's surroundings.
• Damage to the parietal lobe can cause neglect of one side of space.
• Facial recognition is mediated by temporal association areas.

What is Happening in the Posterior Parietal Cortex?

• The Posterior Parietal Cortex is active during sensorimotor activities.
• Its functions include sensorimotor transformation, movement planning via internal maps of body parts (eye, head, trunk, limbs), and formation of internal models and coordinate transformations.

Role of Sensory Information in Anticipatory Control of Reach and Grasp

• Vision helps locate and determine the direction of a reaching movement.
• Sensory information (e.g., visual and somatosensory) aids in determining initial limb position and coordination for grip.

Role of Sensory Feedback to Reach and Grasp

• Visual feedback is vital for fine-tuning movement accuracy, while somatosensory feedback is crucial for controlling complex movements.
• Absence of visual feedback can lead to less accurate movements in most cases.
• Continuous visual guidance helps regulate movements during complex manipulations, such as solving puzzles.

Motor System in Reach and Grasping: Execution of Movement

• Premotor and primary motor cortices receive inputs from the posterior parietal cortex.
• They process the intended movement, including target location-direction and hand formation-orientation.

Two Separate Descending Pathways for Reach and Grasp

• Separate spinal pathways control reaching and hand movements.
• “Transport” and “Grasp” components are controlled by distinct pathways, emphasizing that separate cortical and subcortical networks play distinct roles in controlling distinct elements of reach and grasp tasks.

Musculoskeletal Contributions

• Neural and musculoskeletal systems interact.
• Changes impact movement commands if range of motion or muscle tone changes.
• Compensation occurs during reaching movements when limb capabilities are limited, such as reduced elbow extension when there is reduced range of movement.

Postural Support of Reaching and Grasping

• Postural adjustments (anticipatory and reactive) maintain equilibrium and alignment while reaching and grasping.

Motor Control Elements

• Posture, Reach, and Grasp-manipulation are the motor control elements controlled by their respective pathways.

Grasping Patterns

• Grasping patterns, including power grips (e.g., for heavy objects) and precision grips (e.g., for delicate objects), vary in their characteristics/applications.

Anticipatory Control of Grasp and Lift

• Anticipatory control is crucial for grip formation and maintaining grasp for stability.
• The nervous system adjusts grips depending on the weight or surface of the object.

Coordination of Reach and Grasp

• Reach and grasp movements are coupled kinematically, with consistent patterns.
• Rules for movement (e.g., timing of transport and hand opening) are stored.
• Other factors like direction, speed, and grasp types modify the patterns.

Reaction Time (RT)

• Reaction time measures the time it takes to process sensory information and initiate a movement.
• It is a basic research tool to understand discrete actions, such as reaching.
• Reaction time increases when visual processing and motor response selections are complex.

Simple vs. Choice Reaction Time

• Simple RT involves a single stimulus and response.
• Choice RT involves multiple stimulus-response possibilities.
• Choice RT generally takes longer due to increased processing time.

Fitt’s Law of Movement

• Fitt's Law describes the trade-off between speed and accuracy in movements that involve reaching and grasping.
• Movement time increases with increasing distance and accuracy demands.

Theories of Reaching Control

• Distance and location programming theories describe how the CNS controls reaching movements.
• Distance programming heavily relies on initial visual perception.
• Muscle stiffness is adjusted based on the location/direction of a target to be reached.

Interference between Reaching and Cognitive Tasks

• Dual-task paradigms demonstrate interference between cognitive and motor tasks that require reaching and grasping.
• Completing a cognitive task while reaching leads to slower movement onset times.

Prefrontal Cortex and Limbic System Influence

• Prefrontal cortex plays a key role in motivation, stopping actions, and higher-level motor planning.
• The limbic system is involved in goal-directed behaviors.

Conceptual Mapping of Neural Control of Reach and Grasp

• A conceptual map is suggested to integrate different concepts.

What Might Be the Elements of the Conceptual Map?

• The brain regions (e.g., visual cortex, parietal cortex, prefrontal cortex), pathways, and processes involved in reaching and grasping are outlined.
• Factors include target location, body schema, sensory processing (visual, somatosensory), and motor processing.

Extrapolate Reaching and Grasping Research

• Research on reaching and grasping in the upper extremity impacts other similar complex movement tasks.

Test your knowledge on the key aspects of upper extremity (UE) function! This quiz covers important factors involved in assessing UE function, including motor control and rehabilitation. Discover what is crucial for tasks like reaching, grasping, and manipulating objects in everyday life.