Classification and diagnosis of dysarthria

What is Differential Diagnosis?

Method used by docotrs to tell the difference between conditions that share the same signs or symptoms

What is the importance of differential diagnosis?

1. To define clinical condition

2. To help localise and diagnose underlying neurological conditions

3. To guide management decisions

4. To support prognostic reasoning

Characterising MSD variables relevant to neurological and etiologic perspectives

• Age of onset

• Site of lesion

• Neurologic Diagnosis

• Pathophyoiology ( eg. weakness, strength)

Characterising MSD variables relevant to the speech disorders themselves

• Speech components involved

• Severity

• Salient Features

• Deviant speech/perceptual characteristics

What is Dysarthria?

a collective name for a group of speech disorders resulting from disturbances in muscular control over the speech mechanism

What are the subtypes of Dysarthria

1. Localisation (Leison Site)

2. Pathophysiology (Clinical Characteristics/signs)

What are the mechanisms and subsystems involved in communication

1. Respiration

2. Phonation

3. Articulation

4. Resonance

5. Prosody

What are the solient features use to study MSD

1. Strength (Flaccid Dysarthria)

2. Speed (Spastic Dysarthria)

3. Range (Ataxic Dysarthia/hyper kinetic)

4. Steadiness (Hyperkinetic Dysarthria)

5. Tone

6. Accuracy

What is Flaccid Dysarthia associated with?

Damage to LMN (Nuclei or cranial/spinal neurons, their exons and neurotransmuscular junctions)

What are the Neuromuscular basics of Flaccid Dysarthia?

1. Reduced force of muscle contraction

2. Reduced range of individual movements

What are the perceptual features of Flaccid Dysarthia?

1. Audible inspiration or stridor

2. Continuous breathiness

3. Nasal emission

4. Hypernasality

5. Short phrases

What are the clinical characterisitcs of Flaccid Dysarthia?

1. Weakness and flaccidity

2. Atrophy

3. Fasciculations

4. Hypoactive gag reflex

5. Quivering facial muscles

6. Rapid deterioration and recovery with rest

7. Synkesis (involuntary contraction of muscles)

8. Nasal backflow while swallowing

What is Spastic Dysarthia associated with?

Results from bilateral damage to the UMN system

What are the Neuromuscular basics of Spastic Dysarthia?

1. Spasticity + weakness (slows movements and reduces range)

What are the perceptual features of Spastic Dysarthia?

1. Strained-harsh (strangled) voice quality

2. Low pitch

3. Slow rate

4. Slow and regular AMRs (primary distinguishing feature)

What are the clinical characteristics of spastic dysarthria?

1. Hyperactive reflexes

2. Dysphagia

3. Pathologic oral reflexes (sucking reflex; snout reflex; jaw jerk reflex)

What is Unilateral UMN Dysarthia associated with?

Results fron unilateral damage to the UMN system

What are the Neuromuscular basics of Unilateral UMN Dysarthia?

1. Mild weakness + Spasticity ( reduced range of movement)

What are the perceptual features of Unilateral UMN Dysarthia?

1. Imprecise articulation (consonants)

2. Irregular articulatory breakdown

3. Slow rate

4. Slow AMRs

5. Imprecise AMRs

What are the clinical characteristics of Unilateral UMN dysarthria?

1. Unilateral lower face weakness

2. Unilateral lingual weakness without atrophy/fasciculations

3. Spasticity (difficult to see in speech muscles but can see in limbs)

4. Nonverbal oral apraxia

What is Ataxic Dysarthia associated with?

Damage to the cerebellum control circuit

What are the Neuromuscular basics of Ataxic Dysarthia?

1. Incoordination (slow and inaccuracy in the force, range, timing and direction of speech movement)

What are the perceptual features of Ataxic Dysarthia?

1. Excessive loudness variation

2. Irregular articulatory breakdowns

3. Prolonged phonemes

4. Distorted vowels

5. Excess and equal stress

What are the clinical characteristics of Ataxic dysarthria?

1. Poorly coordinated jaw, face, and tongue movement (undershoot/overshoot to intended position

2. Tremor of the head

3. Disorganised thought

What is Hypokinetic Dysarthia associated with?

Damage to the basal ganglia control circuits

What are the Neuromuscular basics of Hypokinetic Dysarthia?

Damoebed movement

What are the perceptual features of Hypokinetic Dysarthia?

1. Monopitch

2. Monoloud

3. Variable rate

4. Increased rate of speech

5. Short rushes of speech

6. Inappropriate silences

7. Reduced stress

What are the clinical characteristics of Hypokinetic dysarthria?

1. ‘Masked’ facial expression

2. Tremors in jaw, lips, tongue

3. Reduced range of motion

4. Resting tremor

5. Rigidity

6. Difficulty initiating movements (bradykinesia)

What is Hyperkinetic Dysarthia associated with?

Damage to the basal ganglia control circuits

What are the Neuromuscular basics of Hyperkinetic Dysarthia?

Too much movement

What are the perceptual features of Hyperkinetic Dysarthia?

1. Excess loudness variations

2. Transient breathiness

3. Strain strangled voice (intermittent)-

4. Voice stoppages

5. Harsh voice

6. Voice tremor

7. Irregular articulatory breakdown

What are the clinical characteristics of Hyperkinetic dysarthria?

1. Involuntary movements: head, jaw, face, tongue, velar, laryngeal, and respiratory muscles

2. Sustained deviation of head position

3. Motor tics ++

4. Myoclonus of palate, pharynx, larynx, lips, nares, tongue, or respiratory muscles

5. Tremor: Jaw, lip, tongue, pharyngeal, or palate

6. Facial grimacing during speech