Exam 2: Sensation Eval and Intervention

Sensation refers to

stimulation of nerve cells from environment in the sense organs

-auditory

-gustatory

-olfactory

-somatosensory (receiving and interpreting touch)

-vestibular

-visual

What makes up the vestibular system?

vision, ear, and proprioception

Sensory info is received and organized somatotopically in the ________ of the brain

primary somatosensory cortex AKA postcentral gyrus

A large area of receptors on the brain indicates _________

a high density of sensory receptors

Primary somatosensory behaviors originate from what area of the brain?

the post central gyrus

What areas of the body receive a lot of sensation?

hands

lips

face

What happens in our body/muscles and brain when we touch something that is too hot?

1) painful stimulus

2) nociceptors fire

3) impulse is sent to spinal column

4) column splits

-to muscle (motor - reflexively pull hand away if water too hot; without it having to be processed by brain)

-to brain (sensory - if still too hot, then brain adjusts w/o reflex)

If a person sustained a lesion to their primary somatosensory cortex, they may experience ______ and a reduction in _______

may experience: (most impacted; occupation most impacted)

-agraphasthesia

-astereognosis

-hemihyperesthesia

-loss of vibration, proprioception, and fine touch

reduction in: (less impacted)

-nociception

-thermoception

-crude touch

What is graphasthesia? Most or least impacted?

the ability to recognize writing on the skin purely by the sensation of touch

a person may have agraphasthesia if they have a lesion to their primary somatosensory cortex/postcentral gyrus

most impacted

What is streognosis? Most or least impacted?

the ability to perceive and recognize form of an object with vision and auditory occluded by using tactile information to provide cues from texture, spatial properties, temp., etc.

a person may astereognosis if they have a lesion to their primary somatosensory cortex/postcentral gyrus

most impacted

What is hemihypesthesia? Most or least impacted?

-increased sensitivity to sensory stimuli, such as touch, pain, or temperature, on one side of the body

-this heightened sensitivity can result in exaggerated or uncomfortable sensations in response to stimuli that are typically not painful or only mildly uncomfortable.

one side normal, the other side not

-i.e. L hemihypesthesia, the R side detects normally and the L side is affected

most impacted

What is nociception? Most or least impacted?

perception of pain

least impacted

What is thermoception? Most or least impacted?

temperature sensation

least impacted

What is crude touch? Most or least impacted?

gross touch or non-discriminative touch, refers to the ability to perceive touch and pressure on the skin without the ability to precisely locate the point of contact or distinguish between fine detail

allows individuals to sense when they are being touched, but without the ability to discern fine details

"i'm being touched or not being touched"

least impacted

What is tactile perception? What are the 4 hallmarks of tactile perception?

-ability to detect and interpret sensory information cutaneous (skin)

includes:

1) pressure

2) skin stretch

3) vibration

4) temperature

T or F: Normal tactile perception means that an individual can interpret pressure, skin stretch, vibration, and temperature.

true

"P.S. Very Tactile" - "P.S." as a reminder that these sensations are "Very Tactile"

What is pressure?

-how much pressure is applied to a certain area on skin

-can be a lot, can be a little (greater than, less than)

i.e. a light hug vs a tight hug

What is skin stretch?

-part of the cutaneous tactile experience that is caused by friction between the skin and the grasped object

-interacting with stiffer objects causes larger force, and results in a larger amount of skin stretch

our skin provides info on how we manipulate objects in our hand, i.e. holding a bottle and our skin stretches to allow a grasp on the bottle

What is vibration?

-ability to detect vibrations from an object and feel when it starts and stops

Sensation and the OTPF

-sensation is a body function

-sensation is a component of client factors

-sensation influences both motor and processing aspects of performance skills

-sensory dysfunction may affect performance in areas of occupation

Why is sensation important?

-safety (skin breakdown, frostbite, burns), quality, speed, and effectiveness of motor function, feed forward and feedback

-protection from injury

-performing occupational activities

-provides feedback about the environment

-requires for early learning (childhood, exploration)

-affects motor performance

-essential for effective movement

What are the requirements of normal sensation?

you must have

-reception: somatosensory receptors (detection of stimulus)

-transmission: afferent neurons (fired and sent to PNS and then CNS)

-interpretation: sensory cortex (brain receives and interprets the data)

If a person experiences a loss of sensation, then they will have.........? What does this also mean in terms of vision?

they will have:

-impaired tactile feedback

-slowed/diminished quality of performance

-increased risk of injury

they will require adequate vision for compensation/loss of sensation

-aka they will need their vision to help complete activities safely

Selection of evaluation tools depends on whether the etiology is due to problems with........

the CNS or the PNS

the CNS has ability to reorganize after injury

the PNS cannot reorganize after injury.......??????

Central nervous system injury

-injury to brain and spinal cord

-upper motor neuron injury

-generalized area

includes deficits in: proprioception, stereognosis, temperature, and vibration

Peripheral nervous system injury

-damage to peripheral nerves

-lower motor neuron injury

-specific area

includes deficits in: pressure, discrimination, and pain

PPD (peripheral = Pain, Pressure, Discrimination)

Neuroplasticity

the ability within the brain to constantly change both the structure and function of many cells in response to experience or trauma

The potential for recovery depends on

-etiology

-severity

-location of lesion

-cognition

-motivation

-ability to learn new strategies

T or F: The somatosensory system processes input from superficial sources, such as the skin, and from deep sources, such as the musculoskeletal system.

true

Superficial sources

skin receptors

PNS receptor

Deep sources

musculoskeletal receptors

PNS receptor

T or F: Sensation is stimulated by receptors in the PNS and is sent through afferent nerves, carrying nerve impulses from the receptors to the brain.

true

What are the different types of somatosensory receptors? What do each of them have?

mechanoreceptors

chemoreceptors

thermoreceptors

nociceptors

each of them have nociceptors

Receptors that respond to touch, pressure, stretch, and vibration.

mechanoreceptors

Receptors that respond to cell injury or damage.

chemoreceptors

Receptors that respond to temperature, i.e. hot and cold

thermoreceptors

Receptors that sense pain when stimulated.

nociceptors

What are the different types of somatosensory dysfunctions?

paresthesia

hypesthesia

hyperalgesia

dysesthesia

allodynia

What is paresthesia

-tingling, electrical, prickling, or burning sensation

-normal sensation alongside atypical/abnormal sensation

Tapping the volar aspect of the wrist may elicit ________ in the distribution of the median nerve in a person who has carpal tunnel syndrome due to the compressive nature of the disease. When such tapping elicits this, it is called Tinel's sign.

paresthesias

What is hyperesthesia?

-abnormal increase in sensitivity to stimuli

-increased sensory pain

ex: touch canvas material and I think it feels like coarse sand paper

What is hyperalgesia?

-increased pain, sense of pain is overly sensitive

-often occurs during nerve regeneration

What is dysesthesia?

-an unpleasant abnormal sensation, whether spontaneous or evoked

-unpleasant, abnormal sense of touch, often experienced as pain

What is allodynia?

-painful response to a normally innocuous stimulus

-severe pain sensation evoked with a stimulus that doesn't normally induce pain

ex: touch a soft pillow and i shriek in pain

A person with complex regional pain syndrome (CRPS), formerly referred to as reflex sympathetic dystrophy (RSD), experiences pain with the mere movement of air wafting over the involved arm. What type of sensory dysfunction is this?

allodynia

Primary sensation

receives and interprets "simple" sensations such as

-awareness of touch

-awareness of pain and temp.

pain and temperature, light touch and pressure, vibration

primitive and simple

Discriminative sensation

receives and interprets more complex and integrated experiences/sensations such as

-location of touch

-stereognosis

-kinesthesia

-2-point discrimination

stereognosis, graphesthesia, two-point discrimination, point localization

What comes first: primary or discriminative?

primary

Pain and temperature, light touch and pressure, vibration, and proprioception. Is this primary or discriminative?

primary

Location of touch, stereognosis, kinesthesia, and 2-point discrimination. Is this primary or discriminative?

discriminative

Because of the central processing of deep sensory input, clients with some ________ lesions (e.g., CVA and multiple sclerosis) are more likely to have deficits in vibration, proprioception, stereognosis, and temperature.

CNS lesions

Those with ______ lesions are more likely to experience deficits in pain, pressure threshold, and two-point discrimination

PNS lesions

vibration, proprioception, stereognosis, temperature.

PNS or CNS?

CNS

pain, pressure threshold, and two-point discrimination

PNS or CNS?

PNS

What is neuropathy?

-disease or dysfunction of one or more peripheral nerves, typically causing numbness or weakness

-dysfunction of the PNS

T or F: Large sensory nerve fibers carry signals of vibration, light touch, and proprioception.

true

T or F: smaller fibers, which are also often not myelinated, transmit messages of temperature and pain.

true

What is the sequence of loss and return of sensation?

1) discriminative touch and proprioception

2) cold

3) heat

4) pain

pain is last to lose and first to return bc it is needed to help survive, it is our "biological warning system"

What is the first sensation to be lost? Returned?

discriminative touch and proprioception

What is the second sensation to be lost? Returned?

cold

What is the third sensation to be lost? Returned?

heat

What is the fourth sensation to be lost? Returned?

pain

What is nerve compression?

-nerve loses mobility, flexibility, or becomes compressed by surrounding tissues; can cause pain and loss of function

-brain is not sending or receiving full sensations

i.e. not grasping object as strongly as should be

seen in carpal tunnel syndrome

What is sheath loss?

-when transmission of signals is slowed down and impulse is weaker

-brain does not receive full info and muscles don't contract as much as brain wanted to because of the weakened transmission

What is nerve disconnection?

-no signals sent or received by brain

-signals unable to make the "jump" between the severed nerve

What is nerve degeneration?

-whole system falls apart; difficulty with conducting speed and receiving

problems controlling movements: tremors, muscular rigidity, slowness beginning and executing movements, alteration in reflexes and problems with balance

cognitive problems (dementia): impaired memory, disorientation, deficiencies in intellectual abilities, language problems, etc.

What is superficial sensation? What does it include?

cutaneous sensation

includes:

-touch, pain, temp,

-2-point discrimination

The _____ parts of the body have a higher density of receptors and smaller receptor fields. This contributes to enhanced fingertip sensation, such as distinguishing between 1 and 2 stimuli that are close together.

distal

What enables us to tell the difference between a penny and a dime?

2-point discrimination

Fine touch: superficial receptors

-light touch

-vibration

-pressure

-hair follicle receptors

Fine touch: subcutaneous receptors

-pressure

-vibration

-skin stretch

What is temperature sensation? What is the clinical relevance?

thermal receptors detection of hot and cold

relevance

-important to test temp. sensation prior to applying thermal modalities

-important to determine safe temp for washing hands/bathing

-safety during meal prep

-compensatory strategies may be a priority (testing water temp with unaffected body part)

What is pain?

-unpleasant sensory and emotional experience associated with actual or potential tissue damage

-experience is subjective and multidimensional

-detected by free nerve endings

What is fast pain?

Pain that is sharp, intense, and easily localized

What is slow pain?

Pain that is dull, achy, and harder to localize

due to tissue damage

harder to localize due to various pathways used

fear, anxiety, and edema may worsen pain

T or F: Intact pain sensation is indicative of available protective sensation

true

What is proprioception?

-awareness of joint position in space due to musculoskeletal sensation

-encompasses joint position, muscle stretch, and deep vibration

-impacts motor learning and adaptation

-commonly affected by neurological disorders

compensatory strategy when impaired = use of vision

If __________ is impaired, it may be difficult to gauge how much pressure to use when holding a paper cup.

proprioception

What is the purpose of a sensory screening and evaluation?

-assesses the extent of sensory loss

-evaluates and documents sensory recovery

-assists in diagnosis

-provides prognostic information (rehab potential)

-determines impairment and functional limitations

-provides directions for OT treatment

How can OTs evaluate sensory function?

1) functional hand tests

2) simulated activities

3) ADL and IADL performance

we ideally want to complete all 3 bc it makes us more confident in our assessment and tx process

What are the basics of a sensory assessment?

-client must have adequate cognition

-vision must be occluded

-body part being tested must be supported w/o providing stimuli

-reduce environmental stimuli

-ensure clients ability to concentrate

-determine appropriate assessment tools

-use standardized methods of administration

Sensory test procedure/process

1) make sure client understands procedure

2) perform trial with vision

3) then perform trial with vision occluded

4) test unaffected side first

5) test affected side second

Sensory screening of the hand

specific sites can be used to reflect larger portions of the hand innervated by the same peripheral nerve

be sure to note and document the appearance of:

-blisters

-altered sweat patterns

-calluses

-scars

-wounds

-atrophy of thenar and hypothenar eminence

-shiny or dry skin

Median nerve screening

thumb tip, index tip, and index proximal phalanx

Ulnar nerve screening

small finger (pinky)

Radial nerve screening

radial back of hand, dorsal thumb web space

Standardized sensory tests

touch pressure

moving and static 2-point discrimination

point localization

vibration threshold

Non-standardized sensory tests

awareness of:

touch, pain, or pinprick

temperature

vibration

stereognosis

moberg pick-up test

proprioception

kinesthesia

Sensory threshold assessments

the least stimulus needed to elicit a response

i.e. light touch, vibration, cutaneous pressure

Tactile discrimination assessment

the number of sensory receptors in an area

i.e. moving and static 2 point discrimination

Proprioception evaluation

awareness of joint position in space

procedure

-vision occluded

-move joint into flexion/extension

-have patient replicate contralateral positioning

-client identifies positioning of joint

screening

-test distally, or more proximally if deficit is noted

Stereognosis evaluation (moberg pick-up test)

uses both touch and proprioception to identify an object in hand

procedure

-vision occluded

-familiar objects are placed in clients hand

-client manipulates object and is asked to identify object or its characteristics

client must have adequate motor function and communication skills

Touch pressure assessment (semmes weinstein monofilaments)

assesses touch pressure threshold – light touch and deep touch

categories

-green: normal

-blue: diminished light touch

-purple: diminished protective sensation

-red: loss of protective sensation

-untestable

Light touch

-superficial skin receptors

-important for fine discriminatory hand use

-indicator of better sensation than having only deep touch pressure awareness

perceive touch through light pressure or use of a cotton ball

assessed with Semmes W. monofilaments

Deep touch

-subcutaneous touch receptor

-important for protective sensation

assessed with Semmes W. monofilaments

Semmes W. monofilaments: Green

normal - light touch and deep pressure WNL

Semmes W. monofilaments: Blue

diminished light touch – safety issue

(fine discriminatory = light touch)

Semmes W. monofilaments: Purple

diminished protective sensation – safety issue & inc. risk of injury

(protective = deep touch)

Semmes W. monofilaments: Red

loss of protective sensation – no response to any stimulus, huge safety issue

(protective = deep touch)

Nerve function tests

ninhydrin test

wrinkle test

nerve conduction studies