Communication Neuroscience of Motor Speech Disorders

1
Communication Neuroscience of Motor Speech
Disorders
2
3 Major Areas of Discussion

• 1. Neuroscience of motor speech disorders
• 2. Communicative aspects of motor speech
  disorders
• 3. Integrated view some opportunities
  

3
3 Major Areas of Discussion

• 1. Neuroscience of motor speech disorders
• Lesion or pathophysiology in relation to
  behavioral disturbances
• Fingerprint of neurologic disorder
• Status and value of classification systems
• 2. Communicative aspects of motor speech
  disorders
• 3. Integrated view some opportunities
  

4
3 Major Areas of Discussion

• 1. Neuroscience of motor speech disorders
• 2. Communicative aspects of motor speech
  disorders
• Loci of disturbances
• Analysis methods
• 3. Integrated view some opportunities
  

5
3 Major Areas of Discussion

• 1. Neuroscience of motor speech disorders
• 2. Communicative aspects of motor speech
  disorders
• 3. Integrated view some opportunities
• A transdisciplinary perspective

6
Levels of Speech Analysis

• Discourse
• Sentence and phrase recitation
• Words
• Segments
• Features or gestures

7
Dysarthria -- What do we know about lesions and
communication?

• Dysarthria subtypes and their significance

8
Darley, Aronson, Brown

• Dysarthria with adjectives
• flaccid
• spastic
• flaccid-spastic
• ataxic
• hypokinetic
• hyperkinetic

9
Flaccid dysarthria

• Hypernasal
• Imprecise consonants
• Breathy voice, monopitch, audible inspiration,
  harsh voice
• Nasal emission
• Short phrases, monoloudness

Articulation Nasality Voice Respiration
Prosody
10
Flaccid dysarthria--some issues and difficulties

• Not reliably identified in studies that
  replicated Darley et al. (Zyski Weisiger, 1986,
  reported only 1 correct identification by
  experienced clinicians)
• Variable features of dysarthria depending on
  cranial nerve(s) affected

11
Cranial nerves in speech

• Jaw movements CNV
• Bilabials (lip sounds) CNVII
• All lingual sounds (vowels and consonants) CNXII
• Phonation CNX
• Velopharyngeal function (nasal vs nonnasal) CNV,
  CNIX, CNX

12
Flaccid
dysarthria
13
Flaccid
dysarthria
Hypoglossal n.
14
Glossopharyngeal n.
Flaccid
dysarthria
Hypoglossal n.
Vagus n.
15
Facial n.
Glossopharyngeal n.
Flaccid
dysarthria
Hypoglossal n.
Vagus n.
16
Flaccid dysarthria(s)

• It is probably best to think of several types of
  flaccid dysarthria, depending on the combination
  of cranial and/or spinal nerves that are damaged
  (cf. Duffy, 1995)
• Therefore, it is difficult to make specific
  statements regarding clinico-anatomic
  relationships

17
Myasthenia Gravis

• Clinical evaluation of 153 patients main
  findings
• ptosis
• diplopia
• dysphagia
• dysphonia or dysarthria
• masticatory impairment

18
Myasthenia Gravis (MG)

• MG is an autoimmune disorder that affects
  receptors at the neuromuscular junction.
• Cardinal symptoms are weakness and progressive
  fatigue.
• More common in women than men under the age of
  30, but above age 70 it is about equal for the
  two sexes

19
MG - Diagnosis

• Diagnosis is often supported by the Tensilon
  test.
• Tensilon (edrophonium) is injected and the
  patient is observed for improvement.

20
Spastic Dysarthria

• Imprecise consonants
• Monopitch, harsh voice, pitch level,
  strain-strangled voice
• Monoloudness, short phrases
• Reduced stress, slow rate

Articulation Voice Respiration Prosody
21
Spastic Dysarthria

• Associated especially with bilateral damage to
  pyramidal motor system (as in stroke)
• Unilateral damage associated with a milder,
  typically transient dysarthria

22
Spastic dysarthria
23
Pyramidal Tract Upper Motor
Neuron
24
Equivalence Lesions in Supratentorial Stroke

• Lower motor cortex
• Parietal cortex
• Corona radiata
• Periventricular white matter
• Internal capsule
• Thalamus

25
Dysarthria and Stroke

• Urban et al. (1996) the pathogenesis of
  dysarthria in lacunar stroke is based on
  interruption of the corticolingual projections.
• It was also noted that the type of dysarthria
  was uniform across locations of lesion between
  the corona radiata and the base of the pons.
• Question What kind of dysarthria?

26
Lingual Deviation
Points to weak side
27
Lingual Deviation

• In a study of 300 patients with acute unilateral
  ischemic motor stroke, Umapathi et al. (2000)
  observed tongue deviation in 29 of patients with
  stroke, compared to 5 of controls.
• Of the patients showing tongue deviation, 90 had
  dysarthria and 43 had dysphagia.

28
Importance of Dysarthria

• Can be an early stroke indicator.
• Has predictive value concerning patient outcome.
• Is sometimes considered a severity indicator,
  along with other factors
• Has potential for inferring the site of lesion
  and for documenting changes in neurologic status

29
Dysarthria in stroke

• Dysarthria can be an early stroke indicator
• Work leading to the Out-of-hospital NIH Stroke
  Scale (Kothari et al. 1997) showed that the three
  items of facial palsy, motor arm, and dysarthria
  identified 100 of 74 patients treated in a
  thrombolytic stroke trial.

30
Dysarthria in stroke

• Dysarthria was second only to hemiparesis as a
  presenting symptom of stroke in the stroke
  registry of Malmo, Sweden (Jerntorp Berglund,
  1992).
• Dysarthria has been observed in 35 of survivors
  during the acute phase following stroke and in 15
  to 35 during the chronic phase (Arboix et al.,
  1990 Wade, et al. 1986).

31
Dysarthria and outcome

• In a study of 89 patients with lacunar strokes,
  dysarthria and disability were independent
  predictors of one year mortality (Ryglewicz et
  al., 1997).
• Dysarthria, along with urinary incontinence, sex,
  and prestroke disability, emerged as factors that
  affected functional recovery in 2 large cohorts
  of stroke patients (Tilling et al., 2001).

32
Dysarthria in Stroke

• Auditory perceptual studies indicate that
  dysarthria in stroke is related especially to
  prosodic and phonatory impairment.
• The archetypal dysarthria in stroke may be
  described as having a
• C slow speaking rate,
• C poor maintenance of stress patterns,
• C strain-strangled voice quality.
• Dysarthria in Hemispheric Stroke
• A changing view
• The few acoustic and physiological studies that
  have been done give mixed support the
  auditory-perceptual studies.

33
A new dysarthria? UUMN

• Several papers have described the dysarthria
  associated with unilateral upper motor neuron
  lesions (e.g., Duffy, 1995 Duffy Folger, 1996
  Hartman Abbs, 1992 Murdoch, Thompson,
  Stokes, 1994)
• At this time, the designation is anatomic because
  the underlying physiologic explanation is unclear

34
Dysarthria in Stroke

• Unilateral stroke Unilateral upper motor neuron
  (UUMN) dysarthria predominat type (64 of sample)
• Bilateral stroke UUMN dysarthria predominant
  (45 of sample)

Hwang, Duffy, Kent, Sejvar Thomas, ASHA, 2000
35
Miller (1995) study of stroke

• Narrow phonetic transcription and a comprehensive
  taxonomy of error types to compare the phonetic
  errors in 30 post-stroke individuals
• 6 with spastic dysarthria
• 12 with speech dyspraxia and phonemic paraphasia
  without dysphasia
• 12 with speech dyspraxia and phonemic paraphasia
  with dysphasia

36
Miller (1995) study of stroke

• No consistent segmental patterns across groups
• Implication Phonetic transcription is not
  sensitive to the clinical differences, or the
  syndromes are minimally different

37
Schlenck et al. (1993) Prosody in Stroke

• Studied 84 individuals with stroke, all but 11
  having vascular disease
• Prosodic disturbance depended on severity
• Severe dysarthria short tone units and higher
  mean f0 than controls or mildly impaired Pts
• Mild dysarthria small SD of f0 than controls or
  severely impaired Pts

38
Hemispheric and Brainstem Stroke (Kent et al.)

• Syllable AMR tended to be slow and irregular, and
  consonant production in this task often was
  impaired.
• Phonetic analyses of items with reduced
  intelligibility indicated that the errors
  frequently were complex, involving
• (a) both consonant and vowel in a word, and
• (b) two or three features of consonant error.

39
Hemispheric and Brainstem stroke

• Qualitative acoustic analyses revealed a variety
  of abnormalities, including
• spirantization of stops
• multiple release bursts for stops
• variable and/or inappropriate spectra during
  frication segments
• poor coordination of voicing with supraglottal
  articulation.

40
Dysarthria in Stroke
Instrumental studies reveal

• (1) a variability of performance that was not
  remarkable in auditory-perceptual data
• (2) some evidence of both laryngeal hypofunction
  and hyperfunction
• (3) considerable variability across individuals
  with a similar clinical categorization.

41
Spastic-flaccid dysarthria

• Imprecise consonants, distorted vowels
• Hypernasal
• Harsh voice, monopitch, pitch level
• Monoloudness, short phrases
• Rate, excess and equal stress

Articulation Nasality Voice Respiration
Prosody
42
Spastic- flaccid dysarthria
43
Motor Ctx
UMN
LMN
Medulla
Muscle
44
Motor Ctx
LMN lesion
UMN lesion
Flaccidity Hyptonia Hyporeflexia Fasciculations Fi
brillations Atrophy
Spasticity Hypertonia Hyperreflexia
Muscle
45
ALS - Rehabilitation Issues

• Disease course
• Progressive weakness
• Atrophy
• Spasticity
• Dysarthria
• Dysphagia
• Respiratory compromise

Francis et al., Arch Phys. Med. Rehabl, 80, 1999
46
Patterns of decline in ALS

• Pattern of steady, linear deterioration (Prada et
  al., 1993)
• Pattern of stepwise declines for global functions
  such as speech intelligibility (Yorkston et al.,
  1993)
• Nonlinear relationship between functional loss
  and neuronal pathology
• Symptoms are not evident until about 80 of lower
  motor neurons are lost

47
Challenges in Analyzing the Dysarthria in ALS

• Because ALS is progressive, speech function
  declines until most individuals are nonvocal in
  the terminal stage
• Speech capabilities may be greatly diminished, to
  the point that only one or two syllables can be
  produced
• All speech motor systems are affected, though not
  always to the same degree

48
Assessing Speech in ALS

• Early identification of bulbar symptoms
• Decreased maximum force?
• Specific speech changes (e.g., rate)
• Phonatory function
• Respiratory function
• Articulatory function
• Testing materials

49
Cognitive Dysfunction in ALS

• Cognitive impairments have been noted in several
  recent studies.
• Cognitive changes may be the result of the
  extensive pathogenic processes in ALS, including
  dysfunction of cortical gray and white matter
  (Strong et al., 1996).

50
Cognitive Dysfunction in ALS

• Massman et al. (1996) administered a battery of
  neuropsychological tests to 146 patients with
  typical, sporadic (nonfamilial) ALS
• Clinically significant impairment in more than
  one third of the cohort.
• Strongest risk factors dysarthria, low
  education, severe motor symptoms.
• Nearly half of the patients with dysarthria had
  neuropsychological deficits.

51
Ataxic Dysarthria

• Imprecise consonants, irregular articulatory
  breakdown, distorted vowels
• Harsh voice, monopitch
• Monoloudness
• Excess and equal stress, phonemes prolonged,
  intervals prolonged, rate

Articulatory Voice Respiratory Prosodic
52
Ataxic
dysarthria
53
Cerebellum
Vermis
Cerebellar nuclei
54
Lesions in Ataxic Dysarthria

• Superior cerebellar vermis, both cerebellar
  hemispheres, paravermal and lateral aspects of
  the hemispheres, and left paravermal area
• Paramedian regions of the superior cerebellar
  hemispheres
• Midline structures of vermis and fastigial
  nucleus
• Noncerebellar regions such as frontal cerebral
  cortex, as part of the frontocerebellar tract

55
Cerebellopontocerebral pathways
SMA and PM
Pons
Cerebellum
56
Ataxic Dysarthria

• Multiple sclerosis
• Brainstem or midbrain stroke
• Toxic or metabolic disorders
• Traumatic head injury
• Cancer--from direct effects of a tumor, from
  paraneoplastic syndromes, or from neuromuscular
  toxicity from therapy

57
Perceptual Recognition of Ataxic Dysarthria

• Zyski and Weisiger (1987) reported a very low
  rate of correct identification (less than 10)
  for ataxic dysarthria by their group of
  experienced clinicians.
• However, the group of listeners trained with the
  DAB tapes had a much higher rate of correct
  identification (better than 70).

58
AMR in Ataxic Dysarthria

• Duffy (1995) described irregular syllable
  repetition in ataxic dysarthria as "a distinctive
  and fairly pervasive marker of the disorder"
• Most studies report that repetition is slow and
  irregular.
• Ziegler Wessel (1996) reported that AMR
  accounts for about 70 of the variance in
  severity ratings and about 60 of the variance in
  intelligibility ratings.

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AMR in Ataxic Dysarthria
Control
Ataxic
Syllable
60
AMR in Ataxic Dysarthria

• AMR abnormalities include
• slow rate
• temporal variability (varying)
• syllable/segment durations
• variability of energy maxima and minima across
  syllables.

61
AMR in Ataxic Dysarthria

• The energy variability may reflect respiratory
  instability or dyscoordination akin to the
  ataxic breathing observed with stacking
  movements of the forearm in patients with
  cerebellar impairment (Ebert, Hefter, Dohle,
  Freund, 1995).

62
Syllable-rate Correlations
63
Word Boundaries and Ataxic Dysarthria

• Ataxic dysarthria hinders the ability of
  listeners to determine lexical boundaries in
  samples of the dysarthric speech (Liss, Spitzer,
  Caviness, Adler, Edwards, 2000)
• Consequence of dysrhythmia?

64
Tremor Frequencies in Neurologic Diseases
65
Tremor as Attractor

Movement
Oscillatory pattern of tremor
(3-4 Hz in ataxia)
66
Tremor as Attractor

Movement
Oscillatory pattern of tremor
67
Cerebellar functions

• the dichotomybetween motor processes and
  cognitive processes is inconsistent with the
  organization of behaviors in general andthe role
  of the cerebellum in cognitive processes is not
  only expected but also necessary (Bloedel
  Bracha, 1997)

68
Hypokinetic dysarthria

• Monopitch, harsh voice, breathy voice
• Reduced stress, inappropriate silences, short
  rushes
• Monoloudness
• Imprecise consonants

Articulation Voice Respiration Prosody
69
Hypokinetic Dysarthria

• This dysarthria has been described especially in
  connection with Parkinsons disease or
  parkinsonian syndromes .
• it also has been observed in progressive
  supranuclear palsy (Metter Hanson, 1991) and
  multiple system atrophy (Kluin et al., 1996).

70
PD Speech and Swallowing

• Occurrence rate in individuals with PD
• Dysarthria - 60-80
• Dysphagia - 50
• Drooling- 75

Dysfunction in swallow precedes symptoms, and
the dysphagia has a multifactorial pathogenenis
Impaired bolus transport may be a major factor
in dysphagia
71
Hypokinetic dysarthria
72
Pathophysiology of PD PSP

• Both the globus pallidus internal (GPi) and
  globus pallidus external (GPe) are damaged in
  progressive supranuclear palsy
• Only the internal segment appears to be affected
  in Parkinsons disease
• (Hardman Halliday, 1999a, 1999b)

73
Parkinson disease lesion
Parkinson disease
Globus pallidus
74
Globus Pallidus
External
Internal
GPi
GPe
75
Loss of Dopaminergic Neurons in Substantia Nigra

• Width of substantia nigra pars compacta is
  directly associated with motor function
• Age-related loss of neurons in zona compacta of
  SN is about 6 per year
• Parkinsonism occurs when about 80 to 90 of
  striatal dopamine is lost
• With normal aging, this level would not be
  reached until the age of about 110 years

76
Some Changes with Normal Aging

• Simple reaction time increases at a rate of
  0.5-1.6ms per year, starting at age 20
• Muscle power in arms and legs decreases 21 to 45
  between 20 and 80 years of age
• Various coordination tasks show a loss of 14 to
  27 between 20 and 80 years of age
• Simulated ADL activities show an average loss of
  30 between 20 and 80 years of age

77
Parkinsonian Signs in the Aging

• 467 normal elderly residents over 65 years.
• Bradykinesia in 30 of individuals gt 85.
• Lower extremity rigidity in more than 40 of
  individuals gt 85.
• Gait disturbance (shuffling gait) in 6 of
  individuals in 65-74 age group and 30 of
  individuals in 75-84 age group.

Bennet et al., New Eng. J. Med., 1996
78
Parkinsonian Signs in the Aging

• Presence of 2 or more signs
• 15 in 65-74 age group
• 30 in 75-84 age group
• 52 in 85 age group

Bennet et al., New Eng. J. Med., 1996
79
Review article

• Mahant Stacy Movement disorders and normal
  aging.
• Neurologic Clinics, 19, 2001

80
Cardinal Signs of PD

• 1. Bradykinesia, esp. initiating movements
  such as walking
• 2. Increased tone (rigidity) lead-pipe or
  cogwheel rigidity
• 3. Asymmetric, coarse resting tremor of 3- 7 Hz
  (pill rolling tremor). A
  symmetric tremor of 2-12 Hz may
  develop later.

81
Tremor Frequencies in Neurologic Diseases
82
Parkinsons disease -- cardinal signs

• Bradykinesia
• Rigidity
• Tremor

But there may be more to the story...
83
Parkinsons disease --other impairments

• Sensory scaling
• Scaling of movements
• Sensorimotor integration
• Oral sensation

84
Sensory Impairments in PD?

• Deficit in orofacial kinetic sensitivity
• Poor temporal discrimination for tactile,
  auditory, and visual stimuli
• Inaccuracy in a task of finger tapping in
  synchrony with an auditory cue
• Under-estimation of movements when provided with
  kinesthesia

85
Testing oral sensation on the tongue
Tongue
Tongue depressor
86
PD -- Medical treatments

• Pharmacotherapy
• Dopaminergic
• Dopamine agonists
• Ablative surgery
• Thalamotomy
• Pallidotomy
• Deep brain stimulation

87
Pallidotomy for PD

• Pallidotomy is a neurosurgical procedure that can
  reduce many of the symptoms of Parkinson's
  Disease.
• Does not cure the disease, but can permanently
  eliminate dyskinesias and rigidity, and reduce
  tremor, bradykinesia, masked faces, stooped
  posture, shuffling gait, dystonia and greatly
  improve "on-off" motor fluctuations.

88
Pallidotomy for PD

• In this procedure a pearl-sized heat lesion to
  correct the abnormally discharging nerve cells
  located in the globus pallidus internus is made
  using refined stereotactic techniques.
• The results occur during the treatment while in
  the operating room.

89
Deep Brain Stimulation in PD

• The deep brain stimulator is implanted into the
  thalamus. This electrode is connected to a pulse
  generator that is implanted into the brain via a
  lead wire.
• Activation of the device sends continuous
  electrical pulses to the brain. These electrical
  pulses are responsible for the tremor inhibition
  that can result from the use of this device.
• The stimulator can be turned on or off by holding
  a handheld magnet over the generator.

90
Treating PD and ET speech vs. nonspeech

• Dissimilar outcomes for speech and nonspeech
  motor functions often for
• Fetal dopamine transplants for PD
• Dopaminergic Rx for PD
• Pallidotomy for PD
• Thalamotomy for ET
• Deep brain stimulation for ET

91
Treating Dysarthria in PD

• C Speech exercises for regulation of intensity,
  articulation, and self-monitoring
• C Amplification (voice amplifier or Speech
  EnhancerTM)
• C Pacing board (rate control)
• C Portable delayed auditory feedback (DAF)
• C Prosody training with or without visual
  feedback
• C Phonation (e.g., Lee Silverman Voice Training)

92
Hypokinetic Dysarthria

• Global effects on speech production
• Evidence of
• Abnormal laryngeal function
• Inadequacies of respiratory support
• Deficiencies in upper airway valving and resonance

Adams, 1997 Gentil Pollak, 1995 Murdoch et
al, 1977
93
AMR in Parkinsons Disease

• Reduced rate (Canter, 1965 Dworkin Aronson,
  1986 Gurd et al., 1998 Kruel, 1972 Ludlow et
  al., 1987).
• Normal rate (Ackermann et al., 1995 Connor et
  al., 1989).
• Increased rate (Caligiuri, 1989, Hirose et al.,
  1981 Netsell et al., 1975).
• Articulatory imprecision (Canter, 1965 Ackermann
  et al., 1997 Ackermann Ziegler, 1991).

94
AMR in Parkinsons Disease

• Hirose (1986) drew a parallel between a fast rate
  of speech and the festinating gait often seen in
  PD.
• This is consistent with a factor analysis of the
  Unified Parkinson's Disease Rating Scale (UPDRS)
  in which speech and facial expression loaded on
  the same factor as balance and gait (Stebbins
  Goetz, 1998).

95
Word boundaries in Hypokinetic Dysarthria

• The hypokinetic dysarthria in Parkinson disease
  often is associated with reduced syllabic
  contrastivity (a form of dysprosody), and it
  appears that this speech pattern contributes to
  reduced intelligibility, especially when
  articulatory precision is compromised (Liss,
  Spitzer, Caviness, Adler, Edwards, 1998).

96
Hyperkinetic disorders

• Nonrhythmic
• Dystonia
• Chorea
• Rhythmic
• Essential tremor

97
The Focal Dystonias

• Focal dystonias
• Cervical dystonia
• Blepharospasm
• Oromandibular dystonia
• Spasmodic dystonia
• Limb dystonia
• Pathophysiology Poorly understood

98
Hyperkinetic dysarthria -- Dystonia

• Imprecise consonants, distorted vowels, irregular
  articulatory breakdown
• Harsh voice, monopitch, strain-strangled voice
• Monoloudness

Articulation Voice Respiration Prosody
99
Hyperkinetic dysarthria -- chorea

• Imprecise consonants, distorted vowels, irregular
  articulatory breakdown
• Harsh voice, monopitch, strain-strangled voice
• Monoloudness

Articulation Voice Respiration Prosody
100
Botulinum Toxin A (BTX) as Rx for Oromandibular
dystonia (OMD)

• Participants 162 patients with OMD
• Method BTX injections into masseters and/or
  submentalis complex
• Results
• C Mean global effect was 3.1 /-1.0 where 4
  complete abolition of dystonia
• C Better result for jaw-closing than for
  jaw-opening dystonia

(Tan Jankovic, 1999)
101
Muscle Afferent Block for OMD

• Participants 13 patients with OMD who had not
  responded to pharamaco-therapy or dental
  treatment
• Method Injections of diluted lidocaine alcohol
  to reduce muscle spindle afferent activity
• Results Overall improvement of 58 on
  self-rating scale, with better response for
  jaw-closing than jaw-opening muscles
• Yoshida et al. (1998). Movement Disorders, 13

102
Essential Tremor (ET)

• The most common movement disorder
• Etiology poorly understood
• In speech, most often noticeable in sustained
  phonation
• Can be severe enough to disrupt speech and
  diminish intelligibility

103
Essential Tremor

• Currently, clinical classification relies
  primarily on behavioral characteristics, supposed
  sites of origin, and/or the underlying disease
  process (Findley, 1996)
• There is no effective means to differentiate the
  different forms of central tremor (Deuschl, et
  al., 1996)

104
Essential Tremor - Example

• Recordings of
• Sustained vowel
• Sustained fricative
• Single words
• Sentences

105
Turning to Communication

• Levels of motor organization implications for
  motor speech disorders

106
Levels of Organization -- Examples

• Prosody
• Dimensions of analysis for disordered
  speech/language
• Spatio-temporal control
• Implications for dysarthria and apraxia of speech

107
Three Categories of Prosodic Phenomena

• Meter (or rhythm) is the pattern of stressed and
  unstressed syllables.
• Phrasal stress is the phenomenon of word
  prominence in a phrase (i.e., the accentuation of
  one word in a group of words.
• Boundary cues are pauses, changes in duration, or
  pitch adjustments that mark the ends of language
  units.

108
Prosody - Meter
S W S W S W S
Alternation of strong and weak syllables
109
Analysis of Disorders of Meter

• Variability index
• Mean of discrepancies between successive vowel or
  syllable durations

S1 S2 S3
S4
110
Prosody - Phrasal Stress
S W S W S W S
Stressed word
111
Prosody -- Boundary Effects
S W S W S W S
Lengthening
112
Prosody -- Boundary Effects
S W S W S W S
Glottalization
113
Prosody -- Boundary Effects
S W S W S W S
Strengthening
114
Prosody -- Boundary Effects
S W S W S W S
Reduced articulatory
overlap
115
Articulatory Control

• Spatial targets
• Temporal patterns

116
Apraxia of speech

• Slow rate
• Dysprosody excess and equal stress
• Groping articulation
• Substitutions and distortions
• Errors increase with length/complexity of
  utterance

117
Childhood Apraxia of Speech

• Searching for a marker
• Difficulty reaching and maintaining articulatory
  positions
• Abnormal stress
• Patterns of phonetic errors

118
Childhood Apraxia of Speech Association

• http//www.apraxia.org
• The Bruce and Patricia Hendrix Foundation
• Apraxia-KidsSM

aka Developmental
119
Electropalatograph (EPG)
Electrodes
120
EPG Studies of Articulatory Contact
CAS
Control
121
Does temporal variability arise from spatial
variability?

• Keatings Window model of coarticulation
• Convex targets in Guenthers DIVA model of speech
  production

Goal to determine if spatial and temporal
errors are independent
122
Variability in Jaw Position
Jaw
123
Variability in Jaw and Tongue Position
Tongue
Jaw
124
Variability in Jaw-Lip-Tongue

Tongue
Jaw
Lip
Vocal tract configuration
125
Articulatory Target
Jaw position
Lip position
Sound A
Tongue position
126
Articulatory Target
Jaw position
Lip position
Sound B
Sound A
Tongue position
127
Articulatory Target
Jaw position
Sound C
Lip position
Sound B
Sound A
Tongue position
128
Articulatory Target
Jaw position
Lip position
normal
disordered
Tongue position
129
Intelligibility and its partners

• Intelligibility (rating, words correctly
  identified, etc.)
• Communicative efficiency (number of intelligible
  words per unit of time)
• Comprehensibility
• Ease (or difficulty) of understanding

130
Part 3 Transdisciplinary view of motor disorders

• Motor program, anyone?

131
Issues under Discussion

• Learning motor skills
• Neural representation of motor skill
• Relearning motor skills after neural damage or
  structural changes

132
Speech Motor ControlA New (Old?) Perspective

• Convergent evidence from
• Behavioral studies
• Neurophysiologic studies
• Clinical studies
• Developmental studies

133
Two Opposing Theories of Motor Control

• GMP Generalized Motor Program
• Supposes that an internal representation of some
  kind regulates movements
• DS Dynamic Systems
• The motor system self-organizes to achieve stable
  coordinated movements, taking into account the
  task requirements and the biomechanical
  properties of the motor system

134
DS versus GMP

• One fundamental difference the need for a mental
  representation of movementdenied by DS but
  affirmed by GMP
• The early proponents of DS argued long and hard
  against any need for a motor program or mental
  representation

135
BEHAVIORAL STUDIES

• Recommended review paper Wulf et al (1999), Int.
  J. Sport Psychol.

Recommended application paper Holmes Collins
(2001), J. Applied Sport Psychol.
136
Effects of Non-movement Practice

• DS proposed that the motor system self-organizes
  to achieve stable coordinated patterns
  non-movement practice should contribute little if
  anything

137
Effects of Non-movement Practice

• DS proposes that the motor system self-organizes
  to achieve stable coordinated movements
  nonmovement practice should contribute little
• Counterevidence to DS
• Mental practice (imagery)
• Observational learning

138
Mental Imagery and Observational Learning

• Several studies indicate that imagining a
  movement can facilitate the learning of that
  movement
• Similarly, studies show that observing another
  individual perform a movement helps in acquiring
  a motor skill
• Imagery and observation point to a mental
  representation of some kind

139
Reversal Effects

• DS predicts that concurrent feedback ensures the
  best motor performance

140
Reversal Effects

• DS predicts that concurrent feedback ensures the
  best motor performance
• Counterevidence to DS
• Feedback
• Contextual interference

141
Relevant Speech Studies -1

• Adams Page (2000)
• Learning a phrase with target duration
• 3 different feedback/practice conditions
• Better retention for
• Summary feedback after every 5 trials than after
  every trial
• Random practice than blocked practice
• Multiple tasks than single task

142
Relevant Speech Studies - 2

• Steinhauer Grayhack (2000)
• Learning a novel vowel nasalization task
• Subject received 100, 50 or no KR
• Increase in relative frequency of KR led to
  decrease in motor performance and learning
• Worst condition 100 KR

143
Relevant Speech Studies - 3

• Knock et al. (2000)
• Treatment for apraxia of speech
• 2 patients with severe speech disorder
• Random practice facilitated retention, but
  blocked practice did not

144
Intention (cognitive mediating strategies)

• DS does not predict an explicit role of
• learner goals
• intentional control
• instructions

145
Intention (cognitive mediating strategies)

• DS does not predict an explicit role of learner
  goals, intentional control, or instructions
• Counterevidence to DS
• Goal setting
• Attentional focus
• Self control
• Instructions

146
Principles of Motor Learning (Schmidt Bjork,
1996)

• 1. Acquisition performance is not a good index of
  retention.
• 2. Random practice is superior to blocked
  practice (drills)
• 3. Expanding interval retrieval practice is
  superior to massed practice
• 4. Variable practice is superior to constant
  practice

147
Principles of Motor Learning...

• 5. Faded or inconsistent feedback is superior to
  consistent feedback.
• MORAL make things difficult in early learning to
  maximize the learning result.

148
NEUROPHYSIOLOGIC STUDIES

• Motor cortex, basal ganglia, cerebellum
• Mirror neurons

149
Motor Cortex

• Georgopoulos (2000) points out that this region
  is involved with several cognitive functions
• Spatial transformations
• Serial order coding
• Stimulus-response incompatibility
• Motor learning
• Motor imagery

Motor cortex motor control par excellence
150
Motor cortex - plasticity

• Plasticity of MI representations
• following pathology or trauma
• In everyday experience, including motor skill
  learning and cognitive motor actions
• MI cortex contains a dynamic substrate that
  participates in motor learning and possibly in
  cognitive events as well (Sanes Donoghue, Ann.
  Rev. Neuroscience, 2000)
  

151
Basal ganglia (BG)

• Not just for motor control, but also
• BG participate in multiple circuits with
  cognitive areas of cerebral cortex
• Regions of BG show neuronal activation related
  more to cognitive/sensory than to motor functions
• Lesions of BG sometimes result in cognitive or
  sensory disturbances without gross motor
  disturbances

152
Cerebellum

• Many recent reports point to cognitive functions
  of the cerebellum
• the dichotomybetween motor processes and
  cognitive processes is inconsistent with the
  organization of behaviors in general andthe role
  of the cerebellum in cognitive processes is not
  only expected but also necessary (Bloedel
  Bracha, 1997)

153
Cerebellar Activation in 3 tasks

• Observing movements performed by others
• Imagining movements
• Execution of movements

154
Mirror Neurons

• Neurons in the rostral part of monkey inferior
  area 6 (area F5) discharge during active
  movements of the hand, mouth, or both (Kurata
  Tanji, 1986)
• Neurons in this same area also discharge either
  when the monkey performs an action or observes
  the experimenter performing the action
  (Rizzolatti Arbib, 1998)

155
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156
Extending the Role of Mirror Neurons (MNs)

• MNs discharge during the execution of hand
  movements
• MNs discharge during the observation of the same
  actions by others
• MNs discharge when the final part of the action
  is hidden and can only be inferred (Umilta et al,
  2001)

157
Mirror Neurons in Humans

• Transcranial magnetic stimulation (Fadiga et al.,
  1995)
• Positron emission tomography (Grafton et al.,
  1996 Rizzolatti et al., 1996)
• Neuromagnetic recordings (Nishitani Hari, 2000)
• Functional magnetic resonance imaging (Binkofski
  et al, 2000)

158
By Hand, by Foot, or by Mouth
Non-object Action
Premotor Ctx
by hand
(Somatotopic pattern)
by foot
by mouth
Premotor Ctx
Object Action
Post. parietal lobe
by hand
by foot
by mouth
159
Mirror NeuronsGeneral Functions

• Action-perception linkage
• Resonance behaviors (Rizzolatti et al., 1999)
• Replication code for speech (Skoyles, 1999)
• Communicative gestures or articulatory synergies
  (Binkofski et al., 2000)

160
Why Have Mirror Neurons?

• To recognize actions
• To judge the feasibility of an action
• To recognize tools
• To learn by observation
• To imitate the action performed by anotherto
  learn efficiently
• To establish empathy with another

161
Mirror Neurons

• In humans, Brocas area is thought to be one
  cortical site of mirror neurons
• Brocas area not consistently activated during
  single-word production
• Brocas area typically activated during
  syntactic/hierarchical processing

162
CLINICAL STUDIES

• Stroke
• Parkinson disease
• Brain-to-computer communication
• Developmental coordination disorder
• Autism
• Adaptations to altered structure (Compensation)

163
Recovery of Motor Function in Stroke

• Mental practice improved line tracing in 3
  persons with right hemiparesis (Yoo, Park,
  Chung, 2001)
• Subjects traced a line 5.9 inches long, with and
  without cognitive rehearsal

164
Mean-line length errors
165
Recovery of motor function 5 months after
parietal infarct

• 56-year-old man with stable motor deficits
• Physical therapy plus audiotape instruction to
  imagine himself using the affected limb
• Result reduction in impairment and improved arm
  function

166
Parkinson Disease

• Transcranial magnetic stimulation used to map
  cortical representations of ADM during rest,
  contraction, and motor imagery
• Compared to controls, persons with PD had reduced
  area of representation elicited by motor imagery
  in the clinically affected hemisphere (Filippi
  et al., 2001)

167
Parkinson Disease

• PET study of rCBF in patients with PD and
  neurologically normal controls under 3
  conditions rest, motor imagery, and motor
  execution
• For imagery, there was a relative reduction of
  activation in dorsolateral and mesial frontal
  cortex (Samuel et al., 2001)

168
Direct Brain-to-computer Communication

• Record and classify circumscribed and transient
  EEG changes during motor imagery
• Use linear discrimination analysis and neural
  networks to classify features
• A tetraplegic patient can operate an EEG-based
  control of a hand orthosis with nearly 100
  accuracyby imagining motor commands
  (Pfurtscheller Neuper,
  2001)

169
Developmental Coordination Disorder (DCD)

• Visually guided pointing task under 2 load
  conditionswith and without a weight attached to
  a pen
• Control subjects conformed to Fitts law in both
  real and imagined performance
• Subjects with DCD conformed to Fitts law only
  for real movements
• DCD impairs internal representations of movements

170
Infantile Autism

• Possible imitative disturbance
• Difficulties in copying actions
• Difficulties inhibiting stereotyped mimicking
  (e.g., echolalia)

Mirror neurons serve as a bridge between minds
failures of mirror neuron systems could account
for aspects of autism
171
Compensation in speech and voice disorders

• Compensation is one of the most poorly
  understood, but potentially important, aspects of
  rehabilitation/recovery of communication
  disorders
• Successful compensation may depend on an internal
  model that guides the selection and refinement of
  alternative movement patterns

172
Compensation

• Examples from neurologically intact individuals
• Dental appliances
• jaw fixation by bite block
• transient perturbations to movement
• modification of oral anatomy by artificial palate
• alterations of sensory feedback

173
Compensation

• Clinical examples
• laryngectomy
• glossectomy
• osteotomy
• other ablative surgeries or trauma

174
Compensation and internal models

• Sorokin et al (1998) suggested that compensation
  by laryngectomized individuals may depend on an
  internal model that reassigns muscles to
  accomplish phonetic distinctions
• Internal model mental representation

175
Speech Development in Infants
Babbling
Adult speech
Sensorimotor transforms
Internal representations of movements and their
sensory consequences
176
Modeled Behavior
Sensory Analysis
Perspective taking
Initial Representation
Feedback
Movement Sequence
Motor Program
SR2
SR3
SR1
M o t o r A c t
177
Robotics and neural networks

• Efforts to design autonomous humanoid robots have
  focused on imitation learning because it pertains
  to
• Efficient motor learning
• Connection between action and perception
• Modular control in the form of movement
  primitives
  (Schaal, 1999)

178
Computers learning to speak

• Bailly (1997) developed a computer-based
  articulatory model that learns to speak using
  four steps
• Babbling is used to build up a model of forward
  transforms that guide actions
• Imitation is the means by which sound sequences
  can be reproduced using audio-visual to
  articulatory inversion

179
Computers learning to speak

• Bailly (1997) continued
• A process referred to as shaping determines the
  most efficient sensorimotor representation (this
  can be accompanied by response selection and
  tuning)
• Rhythmic coordination is applied to assemble
  sequences of motor patterns for linguistic
  expression

180
Babbling Builds forward transforms
Imitation Defines sensory-motor inversions
Mirror neurons
Neonatal imitation
Optimizes neural representation
Shaping
Rhythmic coordination Assembles sequences
Refines movements
181
Substrates for Speech Acquisition in Infancy

• Imitation in neonates and infants
• Visual-motor reproduction
• Auditory-motor reproduction
• Babbling
• Auditory-motor refinement
• Limb-vocal coordination (hand banging and
  canonical babbling

182
Substrates for Speech Acquisition in Infancy

• Parentese
• Vocal patterns
• Signed patterns
• Continuity between babbling and early words
  syllable structures and sound types.

183
Where to go from here

• J. Pressing (1999). The referential dynamics of
  cognition and action. Psychological Review, 106,
  714-747
• Reconciles dynamical and information-processing
  accounts of action and cognition