Apraxia: Face, Tongue, Ideomotor, and Constructional

Apraxia

The inability to perform a voluntary act even though the motor system, sensory system, and mental status are relatively intact.

Face-tongue Apraxia

The inability to efficiently produce or imitate movements involving the face, tongue, mouth, jaw, or palate on command.

Ideomotor Apraxia

Apraxic patients are often unaware of their deficits and may do an act automatically that they cannot do on command.

Constructional Apraxia

A form of apraxia that affects the ability to construct or draw objects.

Technique to test Face-tongue Apraxia

Ask the Pt to protrude the tongue and move it up, down, right, and left and lick the lips.

Technique to test Ideomotor Apraxia

Ask the patient to demonstrate a sequence: how to use silverware, thread a needle, strike a match and light a candle, and use a key to lock and unlock a lock, or use scissors or other tools.

Common Causes of Apraxia

Left hemisphere lesions, particularly in Broca's area (inferior frontal gyrus).

Distinction between Apraxia and Other Motor Deficits

Impairment in performing learned, skilled movements on command while still being able to perform them automatically in a natural context.

Pyramidal Lesions

Frequently associated with stroke, Alzheimer's disease, or Parkinson's disease.

Cerebellar Lesion

The Pt with a cerebellar lesion retains the ability to perform an act but cannot perform it smoothly.

Basal Motor Nuclei Lesions

Involuntary movements or rigidity impede down the act, but the sequence of the act remains possible.

Formal Criteria to Distinguish Apraxia from other Motor Defects

The Pt's motor system is sufficiently intact to execute the act, the Pt's sensorium is sufficiently intact to understand the act, the Pt comprehends and attempts to cooperate, the Pt's previous skills were sufficient to perform the act, and the Pt has an organic cerebral lesion as the cause of the deficit.

Patients struggle with tasks such as

Blowing a kiss, sticking out the tongue, puffing cheeks, whistling, and licking lips.

Apraxia and Reflexive Actions

Patients may still perform these actions reflexively (e.g., licking lips when eating).

Lesions associated with Ideomotor Apraxia

Occurs with lesions of the language-dominant hemisphere, almost always the left.

Aphasia and Ideomotor Apraxia

Usually the patients with ideomotor apraxia also have aphasia.

Unilateral Lesion Effects

Both hands are usually affected, although the lesion is unilateral.

Buccofacial / Orofacial Apraxia

Another name for Face-tongue Apraxia.

Motor System Integrity

The paralysis precludes doing the act voluntarily or automatically, thus violating a necessary condition that the motor system be fairly intact.

Complicated Apraxias

More complicated apraxias such as ideomotor apraxia require sequential actions.

Constructional Apraxia

The inability of patients to copy accurately drawings or three-dimensional constructions.

Ideomotor Apraxia

A type of apraxia associated with the left parietal lobe, premotor cortex, and sometimes supplementary motor areas.

Face tongue Apraxia

A type of apraxia associated with the left frontal lobe and Broca's area.

Right Parietal Lobe Damage

Leads to more severe impairment in spatial perception, such as neglecting one side of space and producing distorted drawings.

Left Parietal Lobe Damage

Results in more impairment in motor planning, such as difficulty sequencing steps of a drawing.

Somatosensory System

A network of neurons and specialized receptors that allows for the perception of touch, pressure, temperature, pain, and proprioception.

Dorsal Column Tract

Also known as the Dorsal Column-Medial Lemniscus Pathway, it carries fine touch, vibration, and proprioception.

Dermatomes

Specific regions of the skin where sensory information is organized.

Lower Limb Examination

A test to elicit neurological signs in the legs and feet, assessing for altered sensations, numbness, or loss of power of a limb.

Neurological Examination

Includes an assessment of both the motor and sensory systems of the legs.

Misplacement of movements

Using the wrong body part for an action, such as pretending to use a toothbrush with their finger instead of mimicking holding a brush.

Spatial tasks

Both 2D and 3D tasks that patients may struggle with, such as copying geometric figures, arranging blocks in a pattern, drawing a clock face correctly, and assembling a puzzle.

Technique to test Constructional Apraxia

Ask the patient to copy geometric figures (a cross, interlocking pentagons, or clock face) or construct them out of matchsticks.

Patients' spontaneous actions

Patients may spontaneously wave goodbye when saying goodbye to someone, despite struggling to do so when asked.

Brushing hair

Patients may struggle to pretend to brush their hair but can brush their hair when actually holding a brush.

Altered sensations

Patients may present with altered sensations, numbness, or loss of power of a limb during a lower limb examination.

Foot drop

A type of neuropathy that can occur, characterized by difficulty lifting the front part of the foot.

Glove and stocking neuropathy

A type of neuropathy characterized by sensory loss that resembles wearing a glove or stocking.

Spatial perception

The ability to perceive and interpret spatial relationships in the environment.

Motor planning

The ability to plan and execute movements in a coordinated manner.

Premotor Cortex

A part of the brain involved in the planning of movements, associated with ideomotor apraxia.

Dermatome

Each dermatome corresponds to a spinal nerve root that supplies sensation to a particular area of the body.

Mapping

Mapping is important in diagnosing nerve injuries, spinal cord lesions, etc.

Pathway of Sensory Input

Peripheral receptors → Dorsal Columns of the Spinal Cord → synapses in the Medulla → crosses to the opposite side → Thalamus and Somatosensory Cortex.

Spinothalamic Tract

Transmits pain, temperature, and crude touch.

Receptors

Sensory endings are widely distributed and found throughout the body in both somatic and visceral areas.

General Procedure

Key points to remember when testing the sensory function of the lower extremity.

Preparation of the Patient

Make them feel comfortable and relaxed before beginning any test.

Eyes Closed

Ensure the patient has their eyes closed for the assessment.

Demonstrate Normal Sensation

Demonstrate normal sensation on the patient's dermatomal boundaries to minimize the risk of misinterpretation.

L1 Dermatome

Inguinal region and the very top of the medial thigh.

L2 Dermatome

Middle and lateral aspect of the anterior thigh.

L3 Dermatome

Medial aspect of the knee.

L4 Dermatome

Medial aspect of the lower leg and ankle.

L5 Dermatome

Dorsum and medial aspect of the big toe.

S1 Dermatome

Dorsum and lateral aspect of the little toe.

Light (Crude) Touch

Touch impulses ascend to the somesthetic cortex by two spinal pathways.

Anterior Spinothalamic Tract

Decussates at the level of entry of the dorsal root.

Temperature/Pain Perception

Temperature and pain impulses ascend to the somatosensory cortex via the lateral spinothalamic tract.

Dorsal Column or Spinal Lemniscus

Decussates at the cervicomedullary junction.

Lateral Spinothalamic Tract

Decussates at the anterior white commissure.

Types of Pain

Fast - sharp and bright; Slow - dull, diffuse, stinging, or burning pain.

Analgesia

Loss of pain sensation.

Thermoanesthesia

Loss of temperature sensation.

Test Procedure for Light Touch

Ask the patient to say 'touch' in response to each touch by a wisp of cotton.

Test for Temperature

Show patient that you will place two stimuli up and down the trunk to discover a dermatomal loss or spinal cord sensory level around the lower limbs.

Temperature Discrimination Test

Test using different objects (warm and cold tubes or a tuning fork) applied to the legs to assess the patient's ability to distinguish temperature.

Test Procedure for Temperature

Hold the cold object to the different dermatomes of the lower extremities, then replace it with the warm object, starting distally from the foot to the upper thigh.

Screening Purposes for Sensory Examination

Test only the dorsum of the hands and feet, in addition to the face, based on the patient's history.

Quantitative Testing of Touch and Pressure

Involves the use of graded monofilaments and von Frey hairs of different strengths to assess touch and pressure sensitivity.

Pain Perception Test

Involves asking the patient whether they can feel pain after being pricked with a pin while their eyes are closed.

Localization of Touch

After detecting light touch with eyes closed, the patient is asked to place a finger on the exact site touched.

Normal Response to Touch

Patient verbally confirms sensation when lightly touched with a wisp of cotton, with no delay or loss of sensation.

Abnormal Response to Touch

Includes inability to detect coldness/warmth or pain, delayed pain perception, feeling stimulus only on one side, or referred pain.

Sensitivity of Skin Areas

Different areas of the skin exhibit different thresholds for touch; the back and buttocks are less sensitive than the face or fingertips.

Common Pathway for Pain and Temperature

Pain and temperature receptors overlap and share a common pathway in the spinal tract, hence testing for temperature also tests for pain.

Vibration Perception

Dorsal column pathways mediate vibration, with some evidence suggesting pathways may also travel in the dorsal part of the lateral columns.

Interruption of Pathway Effects

Interruption of the pathway from peripheral receptors through the thalamus reduces vibratory perception, with sensory deficits dependent on thalamic injury area.

Suprathalamic Lesions

Suprathalamic lesions more or less spare vibration perception.

Patient's Response to Stimuli

Patient feels the coldness/warmth or pain upon applying the stimulus and should feel the same level of stimulus in both legs.

Testing for Pain

If the patient discriminates temperature normally, there is no need to prick every patient with a pin to test pain.

Delayed Pain Perception

A condition where the patient experiences a delay in feeling pain after a stimulus is applied.

Referred Pain

The site at which the patient feels pain may not correspond to the site of the stimuli.

Testing Procedure for Pain

Prick the patient in each leg from distal to proximal using the same dermatomes.

Preparation of the Patient

Show the patient the pin to be used for pricking and ask them to close their eyes.

Heightened Sensitivity to Touch

Normal cases may exhibit heightened sensitivity to touch.

Patient's Confirmation of Sensation

Patient verbally confirms sensation when lightly touched, indicating normal sensory function.

Vibration Sense

Involves the Dorsal Column Pathway which is related to vibration sensation.

Pallanesthesia

Loss of vibration sense due to lesion or injury in the Dorsal Column Pathway.

Reidel-Seiffer tuning fork

The most practical tool for routine clinical use in quantitative tests of vibration.

Normal Response

Usually coupled with other neurologic tests to verify diagnosis.

Vibration Sense Test

Test where the patient feels the vibration when the tuning fork is applied to a bony prominence.

Test Procedure

Hold a tuning fork (128 or 256 cps) by the round shaft and strike the tines a crisp blow against the ulnar side of your palm.

Abnormal Response

Absent or decreased vibration sensation at distal sites (e.g., great toe).

Delayed Perception

Inability to detect vibration at normal intensity.

Asymmetric Response

Vibration felt on one side but not the other.

Proprioception

Sense of movement, position, and skeletomuscular tension by deep mechanical receptors in muscles, joints, connective tissue, and vestibular system.

Equilibrium Sense

Along with vision and touch, it provides a sense of equilibrium or verticality.

Digital Position Sense Test

Test where the patient is asked to report the position of a digit being wiggled up and down.

Reliability Monitoring

Involves using null tests, varying intensities, and standard anatomic sites to improve accuracy in testing for pallanesthesia.