Hypokinetic dysarthria is a common manifestation of Parkinson's disease, which negatively influences quality of life. Behavioral techniques that aim to improve speech intelligibility constitute the bulk of intervention strategies for this population, as the dysarthria does not often respond vigorously to medical interventions. Although several case and group studies generally support the efficacy of behavioral treatment, much work remains to establish a rigorous evidence base. This absence of definitive research leaves both the speech-language pathologist and referring physician with the task of determining the feasibility and nature of therapy for intelligibility remediation in PD. The purpose of this paper is to introduce a novel framework for medical practitioners in which to conceptualize and justify potential targets for speech remediation. The most commonly targeted deficits (e.g., speaking rate and vocal loudness) can be supported by this approach, as well as underutilized and novel treatment targets that aim at the listener's perceptual skills. 1. Introduction Hypokinetic dysarthria, a common manifestation of Parkinson’s disease (PD), affects roughly 90% of the patient population [1, 2]. Moreover, hypokinetic dysarthria is a prominent feature of more severe and medically refractory parkinsonian disorders (e.g., progressive supranuclear palsy, multiple systems atrophy). Hypokinetic dysarthria is characterized perceptually by varying degrees of reduced pitch variation (monotonicity), reduced loudness, breathy voice, imprecise consonants, variable speaking rate, and short rushes of speech [1, 3, 4]. Reduced intelligibility occurs when these abnormal speech features interfere with the listener’s ability to understand the spoken message. Intelligibility deficits can significantly reduce quality of life, contribute to depression and feelings of isolation, and hinder the ability to maintain gainful employment [5, 6]. Unlike trunk and limb motor impairments in PD, speech deficits typically do not respond vigorously to pharmacological or surgical interventions (see [7, 8] for reviews of the literature). Thus behavioral treatments to improve speech intelligibility constitute the bulk of speech treatment for this population. Behavioral interventions by speech-language pathologists primarily aim to reduce or compensate for the underlying speech deficits to improve speech intelligibility [1]. Despite a growing body literature that generally supports the efficacy of various interventions, much work remains to establish a rigorous evidence base [9–11].
References
[1]
J. R. Duffy, Motor Speech Disorders: Substrates, Differential Diagnosis, and Management, Mosby, St. Louis, Mo, USA, 2005.
[2]
J. A. Logemann, H. B. Fisher, B. Boshes, and E. R. Blonsky, “Frequency and cooccurrence of vocal tract dysfunctions in the speech of a large sample of Parkinson patients,” Journal of Speech and Hearing Disorders, vol. 43, no. 1, pp. 47–57, 1978.
[3]
F. L. Darley, A. E. Aronson, and J. R. Brown, “Differential diagnostic patterns of dysarthria,” Journal of Speech and Hearing Research, vol. 12, no. 2, pp. 246–269, 1969.
[4]
F. L. Darley, A. E. Aronson, and J. R. Brown, “Clusters of deviant speech dimensions in the dysarthrias,” Journal of Speech and Hearing Research, vol. 12, no. 3, pp. 462–496, 1969.
[5]
E. Appleman, K. Stavitsky, and A. Cronin-Golomb, “Relation of subjective quality of life to motor symptom profile in Parkinson's disease,” Parkinson's Disease, vol. 2011, Article ID 472830, 5 pages, 2011.
[6]
N. Miller, E. Noble, D. Jones, and D. Burn, “Hard to swallow: dysphagia in Parkinson's disease,” Age and Ageing, vol. 35, no. 6, pp. 614–618, 2006.
[7]
B. E. Murdoch, “Surgical approaches to treatment of Parkinson's disease: implications for speech function,” International Journal of Speech-Language Pathology, vol. 12, no. 5, pp. 375–384, 2010.
[8]
G. M. Schulz and M. K. Grant, “Effects of speech therapy and pharmacologic and surgical treatments on voice and speech in Parkinson's disease: a review of the literature,” Journal of Communication Disorders, vol. 33, no. 1, pp. 59–88, 2000.
[9]
K. H. Deane, R. Whurr, E. D. Playford, Y. Ben-Shlomo, and C. E. Clarke, “A comparison of speech and language therapy techniques for dysarthria in Parkinson's disease,” The Cochrane Database of Systematic Reviews, no. 2, Article ID CD002814, 2001.
[10]
O. Suchowersky, S. Reich, J. Perlmutter, T. Zesiewicz, G. Gronseth, and W. J. Weiner, “Practice parameter: diagnosis and prognosis of new onset Parkinson disease (an evidence-based review): report of the quality standards subcommittee of the American academy of neurology,” Neurology, vol. 66, no. 7, pp. 968–975, 2006.
[11]
K. M. Yorkston, M. Hakel, D. R. Beukelman, and S. Fager, “Evidence for effectiveness of treatment of loudness, rate, or prosody in dysarthria: a systematic review,” Journal of Medical Speech-Language Pathology, vol. 15, no. 2, pp. xi–xxxvi, 2007.
[12]
P. W. Jusczyk and P. A. Luce, “Speech perception and spoken word recognition: past and present,” Ear & Hearing, vol. 23, no. 1, pp. 2–40, 2002.
[13]
R. E. Remez, P. E. Rubin, D. B. Pisoni, and T. D. Carrell, “Speech perception without traditional speech cues,” Science, vol. 212, no. 4497, pp. 947–950, 1981.
[14]
D. L. Schacter and B. A. Church, “Auditory priming: implicit and explicit memory for words and voices,” Journal of Experimental Psychology, vol. 18, no. 5, pp. 915–930, 1992.
[15]
S. D. Goldinger, “Words and voices: episodic traces in spoken word identification and recognition memory,” Journal of Experimental Psychology: Learning Memory and Cognition, vol. 22, no. 5, pp. 1166–1183, 1996.
[16]
M. H. Davis and I. S. Johnsrude, “Hearing speech sounds: top-down influences on the interface between audition and speech perception,” Hearing Research, vol. 229, no. 1-2, pp. 132–147, 2007.
[17]
M. Baart and J. Vroomen, “Do you see what you are hearing? cross-modal effects of speech sounds on lipreading,” Neuroscience Letters, vol. 471, no. 2, pp. 100–103, 2010.
[18]
H. McGurk and J. MacDonald, “Hearing lips and seeing voices,” Nature, vol. 264, no. 5588, pp. 746–748, 1976.
[19]
A. Cutler and D. M. Carter, “The predominance of strong initial syllables in the English vocabulary,” Computer Speech and Language, vol. 2, no. 3-4, pp. 133–142, 1987.
[20]
S. L. Mattys, L. White, and J. F. Melhorn, “Integration of multiple speech segmentation cues: a hierarchical framework,” Journal of Experimental Psychology, vol. 134, no. 4, pp. 477–500, 2005.
[21]
A. Cutler and S. Butterfield, “Rhythmic cues to speech segmentation: evidence from juncture misperception,” Journal of Memory and Language, vol. 31, no. 2, pp. 218–236, 1992.
[22]
A. Cutler and D. Norris, “The role of strong syllables in segmentation for lexical access,” Journal of Experimental Psychology: Human Perception and Performance, vol. 14, no. 1, pp. 113–121, 1988.
[23]
B. D. Fear, A. Cutler, and S. Butterfield, “The strong/weak syllable distinction in English,” Journal of the Acoustical Society of America, vol. 97, no. 3, pp. 1893–1904, 1995.
[24]
S. Spitzer, J. M. Liss, and S. Mattys, “Acoustic cues to lexical segmentation: a study of resynthesized speech,” Journal of the Acoustical Society of America, vol. 122, no. 6, pp. 3678–3687, 2007.
[25]
B. Lindblom, “Explaining phonetic variation: a sketch of the H and H theory,” in Speech Production and Speech Modeling, W. Hardcastle and A. Marchal, Eds., pp. 403–439, Kluwer Academic, Dodrecht, The Netherlands, 1990.
[26]
P. J. Holcomb, “Semantic priming and stimulus degradation: implications for the role of the N400 in language processing,” Psychophysiology, vol. 30, no. 1, pp. 47–61, 1993.
[27]
J. H. Neely, “Semantic priming and retrieval from lexical memory: roles of inhibitionless spreading activation and limited-capacity attention,” Journal of Experimental Psychology, vol. 106, no. 3, pp. 226–254, 1977.
[28]
J. M. Liss, “Perception of dysarthric speech,” in Motor Speech Disorders: Essays for Ray Kent, G. Weismer, Ed., pp. 187–219, Plural, San Diego, Calif, USA, 2007.
[29]
J. M. Liss, S. M. Spitzer, J. N. Caviness, C. Adler, and B. Edwards, “Syllabic strength and lexical boundary decisions in the perception of hypokinetic dysarthric speech,” Journal of the Acoustical Society of America, vol. 104, no. 4, pp. 2457–2466, 1998.
[30]
J. M. Liss, S. M. Spitzer, J. N. Caviness, C. Adler, and B. Edwards, “Lexical boundary error analysis in hypokinetic and ataxic dysarthria,” Journal of the Acoustical Society of America, vol. 107, no. 6, pp. 3415–3424, 2000.
[31]
J. M. Lissa, S. M. Spitzer, J. N. Caviness, and C. Adler, “The effects of familiarization on intelligibility and lexical segmentation in hypokinetic and ataxic dysarthria,” Journal of the Acoustical Society of America, vol. 112, no. 6, pp. 3022–3030, 2002.
[32]
M. H. Davis, I. S. Johnsrude, A. Hervais-Adelman, K. Taylor, and C. McGettigan, “Lexical information drives perceptual learning of distorted speech: evidence from the comprehension of noise-vocoded sentences,” Journal of Experimental Psychology: General, vol. 134, no. 2, pp. 222–241, 2005.
[33]
M. P. Caligiuri, “The influence of speaking rate on articulatory hypokinesia in Parkinsonian dysarthria,” Brain & Language, vol. 36, no. 3, pp. 493–502, 1989.
[34]
K. M. Yorkston, D. R. Beukelman, E. A. Strand, and K. R. Bell, Management of Motor Speech Disorders in Children and Adults, Pro-Ed, Austin, Tex, USA, 2nd edition, 2000.
[35]
V. L. Hammen and K. M. Yorkston, “Respiratory patterning and variability on dysarthric speech,” Journal of Medical Speech-Language Pathology, vol. 2, pp. 253–262, 1994.
[36]
K. M. Yorkston and D. R. Beukelman, Assessment of Intelligibility of Dysarthric Speech, C. C., Tigard, Ore, USA, 1981.
[37]
K. M. Yorkston, V. L. Hammen, D. R. Beukelman, and C. Traynor, “The effect of rate control on the intelligibility and naturalness of dysarthric speech,” Journal of Speech and Hearing Disorders, vol. 55, no. 3, pp. 550–560, 1990.
[38]
P. Blanchet and G. Snyder, “Speech rate treatments for individuals with dysarthria: a tutorial,” Perceptual and Motor Skills, vol. 110, no. 3, pp. 965–982, 2010.
[39]
G. Van Nuffelen, M. De Bodt, F. Wuyts, and P. Van de Heyning, “The effect of rate control on speech rate and intelligibility of dysarthric speech,” Folia Phoniatrica et Logopaedica, vol. 61, no. 2, pp. 69–75, 2009.
[40]
G. Van Nuffelen, M. De Bodt, J. Vanderwegen, P. Van de Heyning, and F. Wuyts, “Effect of rate control on speech production and intelligibility in dysarthria,” Folia Phoniatrica et Logopaedica, vol. 62, no. 3, pp. 110–119, 2010.
[41]
A. Lowit, C. Dobinson, C. Timmins, P. Howell, and B. Kr？ger, “The effectiveness of traditional methods and altered auditory feedback in improving speech rate and intelligibility in speakers with Parkinson's disease,” International Journal of Speech-Language Pathology, vol. 12, no. 5, pp. 426–436, 2010.
[42]
A. S. Mefferd and J. R. Green, “Articulatory-to-acoustic relations in response to speaking rate and loudness manipulations,” Journal of Speech, Language, and Hearing Research, vol. 53, no. 5, pp. 1206–1219, 2010.
[43]
K. Tjaden and G. Wilding, “Rate and loudness manipulations in dysarthria: acoustic and perceptual findings,” Journal of Speech, Language, and Hearing Research, vol. 47, no. 4, pp. 766–783, 2004.
[44]
A. T. Neel, “Vowel space characteristics and vowel identification accuracy,” Journal of Speech, Language, and Hearing Research, vol. 51, no. 3, pp. 574–585, 2008.
[45]
P. A. McRae, K. Tjaden, and B. Schoonings, “Acoustic and perceptual consequences of articulatory rate change in Parkinson disease,” Journal of Speech, Language, and Hearing Research, vol. 45, no. 1, pp. 35–50, 2002.
[46]
G. S. Turner, K. Tjaden, and G. Weismer, “The influence of speaking rate on vowel space and speech intelligibility for individuals with amyotrophic lateral sclerosis,” Journal of Speech and Hearing Research, vol. 38, no. 5, pp. 1001–1013, 1995.
[47]
G. Weismer, J.-Y. Jeng, J. Laures, R. D. Kent, and J. F. Kent, “Acoustic and intelligibility characteristics of sentence production in neurogenic speech disorders,” Folia Phoniatrica et Logopaedica, vol. 53, no. 1, pp. 1–18, 2001.
[48]
D. G. Hanson, B. R. Gerratt, and P. H. Ward, “Glottographic measurement of vocal dysfuntion. A preliminary report,” The Annals of Otology, Rhinology and Laryngology, vol. 92, no. 5, part 1, pp. 413–420, 1983.
[49]
K. S. Perez, L. O. Ramig, M. E. Smith, and C. Dromey, “The parkinson larynx: tremor and videostroboscopic findings,” Journal of Voice, vol. 10, no. 4, pp. 354–361, 1996.
[50]
N. P. Solomon and T. J. Hixon, “Speech breathing in Parkinson's disease,” Journal of Speech and Hearing Research, vol. 36, no. 2, pp. 294–310, 1993.
[51]
L. O. Ramig, C. Fox, and S. Sapir, “Speech treatment for Parkinson's disease,” Expert Review of Neurotherapeutics, vol. 8, no. 2, pp. 297–309, 2008.
[52]
J. N. Caviness, J. M. Liss, C. Adler, and V. Evidente, “Analysis of high-frequency electroencephalographic-electromyographic coherence elicited by speech and oral nonspeech tasks in Parkinson's disease,” Journal of Speech, Language, and Hearing Research, vol. 49, no. 2, pp. 424–438, 2006.
[53]
M. Trail, C. Fox, L. O. Ramig, S. Sapir, J. Howard, and E. C. Lai, “Speech treatment for Parkinson's disease,” NeuroRehabilitation, vol. 20, no. 3, pp. 205–221, 2005.
[54]
K. K. Baker, L. O. Ramig, E. S. Luschei, and M. E. Smith, “Thyroarytenoid muscle activity associated with hypophonia in Parkinson disease and aging,” Neurology, vol. 51, no. 6, pp. 1592–1598, 1998.
[55]
A. K. Ho, R. Iansek, and J. L. Bradshaw, “Regulation of parkinsonian speech volume: the effect of interlocuter distance,” Journal of Neurology, Neurosurgery & Psychiatry, vol. 67, no. 2, pp. 199–202, 1999.
[56]
R. Oliveira, J. Gurd, P. Nixon, J. Marshall, and R. Passingham, “Micrographia in Parkinson's disease: the effect of providing external cues,” Journal of Neurology, Neurosurgery and Psychiatry, vol. 63, no. 4, pp. 429–433, 1997.
[57]
C. M. Fox, L. O. Raming, M. R. Ciucci, S. Sapir, D. H. McFarland, and B. G. Farley, “The science and practice of LSVT/LOUD: neural plasticity—principled approach to treating individuals with parkinson disease and other nuerological disorders,” Seminars in Speech and Language, vol. 27, no. 4, pp. 283–299, 2006.
LSVT？ Global, LSVT？ LOUD Training and Certification Workshop Brochure, Retrieved from, 2011, http://www.lsvtglobal.com/pdf/RegistrationBrochure.pdf.
[60]
LSVT？ Global, Research Summary, Retrieved from, 2011, http://www.lsvtglobal.com/index.php?action=research-summary/.
[61]
L. O. Ramig, S. Countryman, L. Thompson, and Y. Horii, “Comparison of two forms of intensive speech treatment for Parkinson disease,” Journal of Speech and Hearing Research, vol. 38, no. 6, pp. 1232–1251, 1995.
[62]
L. O. Ramig and C. Dromey, “Aerodynamic mechanisms underlying treatment-related changes in vocal intensity in patients with Parkinson disease,” Journal of Speech, Language, and Hearing Research, vol. 39, no. 4, pp. 798–807, 1996.
[63]
L. O. Ramig, S. Sapir, S. Countryman et al., “Intensive voice treatment (LSVT？) for patients with Parkinson's disease: a 2 year follow up,” Journal of Neurology, Neurosurgery and Psychiatry, vol. 71, no. 4, pp. 493–498, 2001.
[64]
M. P. Cannito, D. M. Suiter, L. Chorna, D. Beverly, T. Wolf, and J. Watkins, “Speech intelligibility in a speaker with idiopathic Parkinson's disease before and after treatment,” Journal of Medical Speech-Language Pathology, vol. 16, pp. 207–212, 2008.
[65]
G. Constantinescu, D. Theodoros, T. Russell, E. Ward, S. Wilson, and R. Wootton, “Assessing disordered speech and voice in Parkinson's disease: a telerehabilitation application,” International Journal of Language and Communication Disorders, vol. 45, no. 6, pp. 630–644, 2010.
[66]
A. Neel, “Effects of loud and amplified speech on sentence and word intelligibility in Parkinson disease,” Journal of Speech, Language, and Hearing Research, vol. 52, no. 4, pp. 1021–1033, 2009.
[67]
K. Tjaden and G. Wilding, “The impact of rate reduction and increased loudness on fundamental frequency characteristics in dysarthria,” Folia Phoniatrica et Logopaedica, vol. 63, no. 4, pp. 178–186, 2011.
[68]
S. Sapir, J. Spielman, L. Ramig, B. Story, and C. Fox, “Effects of intensive voice treatment (LSVT) on vowel articulation in dysarthric individuals with idiopathic Parkinson disease: acoustic and perceptual findings,” Journal of Speech, Language, and Hearing Research, vol. 50, no. 4, pp. 899–912, 2007.
[69]
C. Dromey and L. O. Ramig, “The effect of lung volume on selected phonatory and articulatory variables,” Journal of Speech, Language, and Hearing Research, vol. 41, no. 3, pp. 491–502, 1998.
[70]
R. Schulman, “Articulatory dynamics of loud and normal speech,” Journal of the Acoustical Society of America, vol. 85, no. 1, pp. 295–312, 1989.
[71]
C. Beliveau, M. Hodge, and P. Hagler, “Effects of supplemental linguistic cues on the intelligibility of severely dysarthric speakers,” Augmentative and Alternative Communication, vol. 11, pp. 176–186, 1995.
[72]
P. Dongilli, “Semantic context and speech intelligibility,” in Motor Speech Disorders: Advances in Assessment and Treatment, J. Till, K. Yorkston, and D. Beuk, Eds., pp. 175–191, Paul H. Brookes, Baltimore, Md, USA, 1994.
[73]
J. M. Garcia and P. Dagenais, “Dysarthric sentence intelligibility: contribution of iconic gestures and message predictiveness,” Journal of Speech, Language, and Hearing Research, vol. 41, no. 6, pp. 1282–1293, 1998.
[74]
W. Jones, P. Mathy, T. Azuma, and J. Liss, “The effect of aging and synthetic topic cues on the intelligibility of dysarthric speech,” Augmentative and Alternative Communication, vol. 20, no. 1, pp. 22–29, 2004.
[75]
K. Yorkston, E. Strand, and M. Kennedy, “Comprehensibility of dysarthric speech: implications for assessment and treatment planning,” American Journal of Speech-Language Pathology, vol. 5, no. 1, pp. 55–66, 1996.
[76]
K. M. Yorkston, D. R. Beukelman, and K. C. Hustad, “Optimizing communication effectiveness: bringing it together,” in Clinical Management of Speakers with Motor Speech Disorders, K. Yorkston, D. Beukelman, E. Strand, and K. Bell, Eds., Pro Ed, Austin, Tex, USA, 2nd edition, 1999.
[77]
K. C. Hustad, T. Jones, and S. Dailey, “Implementing speech supplementation strategies: effects on intelligibility and speech rate of individuals with chronic severe dysarthria,” Journal of Speech, Language, and Hearing Research, vol. 46, no. 2, pp. 462–474, 2003.
[78]
V. Hammen, K. Yorkston, and P. Dowden, “Index of contextual intelligibility: impact of semantic context in dysarthria,” in Dysarthria and Apraxia of Speech: Perspectives on Management, C. Moore, K. Yorkston, and D. Beukelman, Eds., Paul H. Brookes, Baltimore, Md, USA, 1991.
[79]
R. Utianski, K. L. Lansford, J. M. Liss, and T. Azuma, “The effects of topic knowledge on intelligibility and lexical segmentation of hypokinetic and ataxic dysarthria,” Journal of Medical Speech-Language Pathology. In press.
[80]
K. D. R. Drager and J. E. Reichle, “Effects of discourse context on the intelligibility of synthesized speech for young adult and older adult listeners: applications for AAC,” Journal of Speech, Language, and Hearing Research, vol. 44, no. 5, pp. 1052–1057, 2001.
[81]
J. M. Garcia and M. Hayden, “Young and older listener understanding of a person with severe dysarthria,” Journal of Medical Speech-Language Pathology, vol. 7, no. 2, pp. 109–112, 1999.
[82]
S. Gordon-Salant and P. J. Fitzgibbons, “Selected cognitive factors and speech recognition performance among young and elderly listeners,” Journal of Speech, Language, and Hearing Research, vol. 40, no. 2, pp. 423–431, 1997.
[83]
S. A. Borrie, M. J. McAuliffe, J. M. Liss, C. Kirk, G. A. O'Beirne, and T. Anderson, “Familiarization conditions and the mechanisms that underlie improved recognition of dysarthric speech,” Submitted to Language & Cognitive Processes.
[84]
A. R. Bradlow and T. Bent, “Perceptual adaptation to non-native speech,” Cognition, vol. 106, no. 2, pp. 707–729, 2008.
[85]
C. M. Clarke and M. F. Garrett, “Rapid adaptation to foreign-accented English,” Journal of the Acoustical Society of America, vol. 116, no. 6, pp. 3647–3658, 2004.
[86]
S. K. Sidaras, J. E. D. Alexander, and L. C. Nygaard, “Perceptual learning of systematic variation in Spanish-accented speech,” Journal of the Acoustical Society of America, vol. 125, no. 5, pp. 3306–3316, 2009.
[87]
J. L. Loebach, T. Bent, and D. B. Pisoni, “Multiple routes to the perceptual learning of speech,” Journal of the Acoustical Society of America, vol. 124, no. 1, pp. 552–561, 2008.
[88]
E. Dupoux and K. Green, “Perceptual adjustment to highly compressed speech: effects of talker and rate changes,” Journal of Experimental Psychology: Human Perception and Performance, vol. 23, no. 3, pp. 914–927, 1997.
[89]
K. K. Tjaden and J. M. Liss, “The role of listener familiarity in the perception of dysarthric speech,” Clinical Linguistics and Phonetics, vol. 9, no. 2, pp. 139–154, 1995.
