Consensus paper: Language and the cerebellum: an ongoing enigma.

In less than three decades, the concept "cerebellar neurocognition" has evolved from a mere afterthought to an entirely new and multifaceted area of neuroscientific research. A close interplay between three main strands of contemporary neuroscience induced a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Indeed, the wealth of current evidence derived from detailed neuroanatomical investigations, functional neuroimaging studies with healthy subjects and patients and in-depth neuropsychological assessment of patients with cerebellar disorders shows that the cerebellum has a cardinal role to play in affective regulation, cognitive processing, and linguistic function. Although considerable progress has been made in models of cerebellar function, controversy remains regarding the exact role of the "linguistic cerebellum" in a broad variety of nonmotor language processes. This consensus paper brings together a range of different viewpoints and opinions regarding the contribution of the cerebellum to language function. Recent developments and insights in the nonmotor modulatory role of the cerebellum in language and some related disorders will be discussed. The role of the cerebellum in speech and language perception, in motor speech planning including apraxia of speech, in verbal working memory, in phonological and semantic verbal fluency, in syntax processing, in the dynamics of language production, in reading and in writing will be addressed. In addition, the functional topography of the linguistic cerebellum and the contribution of the deep nuclei to linguistic function will be briefly discussed. As such, a framework for debate and discussion will be offered in this consensus paper.

Pre-linguistic communication skill development in an infant with a diagnosis of galactosaemia.

BACKGROUND: Neonatal screening for galactosaemia (GAL) identifies the condition early, but subsequent biomedical and genetic testing fails to identify which subgroup of infants with GAL are at most risk of the language disorders associated with the condition. This study aims to present preliminary data on an infant with GAL based on assessment of pre-linguistic communication behaviours known to underpin language development. METHODS: This single case-control study profiles the pre-linguistic skills of a 13-month-old infant with GAL. The Index Infant's performance was descriptively compared to that of a typically developing, suitably matched control infant. RESULTS: The Index Infant was identified as presenting with clinically significant delays on 9 of the 11 pre-linguistic skills assessed. DISCUSSION AND CONCLUSION: The early identification of risk of developmental language difficulties in the Index Infant allows for the implementation of early intervention using the infant's parents as facilitators of language stimulation. Monitoring of the infant's progress is warranted.

Development of figurative language skills following central nervous system-directed chemotherapy delivered in early childhood.

Central nervous system (CNS)-directed chemotherapy is delivered for the treatment of childhood acute lymphoblastic leukaemia (ALL). Figurative language deficits have been described in children following CNS-directed chemotherapy; however, comprehensive analysis of figurative interpretation errors, potentially providing clinical utility to assist with intervention planning, has never been performed. The present study aimed to compare the figurative language skills of seven children treated with CNS-directed chemotherapy for ALL before the age of 6 years (mean age at diagnosis 3 years 10 months) and a matched control group of children, using the Test of Language Competence-Expanded Edition (TLC-E) Figurative Language sub-test. It was hypothesised that the children treated with CNS-directed chemotherapy would demonstrate a decreased performance in and an alternative method of interpreting figurative language. The results suggest no negative effects of CNS-directed chemotherapy on figurative language. There were no statistically significant differences between groups for TLC-E Figurative Language sub-test composite scores and picture component errors, nor were there clinically significant differences observed from descriptive comparisons of individual case data and error analysis. As these skills continue to emerge beyond childhood, the need to monitor skill development in ALL survivors beyond childhood is highlighted.

Long term language recovery subsequent to low frequency rTMS in chronic non-fluent aphasia.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has emerged as a potential therapeutic tool for the rehabilitation of language in chronic non-fluent aphasia post-stroke. Previous studies report that low frequency (1 Hz) rTMS applied to homologous language sites can facilitate behavioural language changes. Improvements in picture naming performance and speech output are frequently reported. OBJECTIVES: This study aims to assess the efficacy of inhibitory rTMS to modulate language performance in non-fluent aphasia. METHODS: Low-frequency (1 Hz) rTMS was applied to six active stimulation and six placebo patients for 20 min per day over 10 days, as outlined in a previous published investigation. Behavioural language outcome measures were taken at baseline (pre-stimulation) and 1 week, 2 months, 8 months and 12 months post-stimulation. RESULTS: The findings demonstrate treatment-related changes observed in the stimulation group, up to 12 months post-stimulation, when compared to the placebo control group over time for naming performance, expressive language and auditory comprehension. CONCLUSION: These outcomes provide considerable evidence to support the theory of rTMS modulating mechanisms of transcallosal disinhibition in the aphasic brain, and highlight the potential clinical application of rTMS for language rehabilitation in chronic aphasia.

Charting a seven-year trajectory of language outcomes for a child with galactosemia.

Cross-sectional methodologies have revealed age-related deterioration in cognitive performance, reflecting progressive neurodegenerative change in a minority of children and adolescents with classic galactosemia (GAL). The application of longitudinal methodologies sensitive to age-related changes at the individual level is needed to determine the extent of any possible decline in function in children with GAL. The authors report on the developmental language outcomes of a 9-year-old female with GAL through an examination of her language development over a 7-year period using a performance tracking system based on the use of raw performance scores required for attainment at the 50th percentile for age. Raw scores typically increase systematically over time and are thus more sensitive to developmental changes. Results suggest that there was no decline in the child's language skills over the course of the investigation. For the case presented, the use of raw scores offered a means of examining the child's patterns of individual change, which revealed stable language skills over the period of monitoring, perhaps indicating a stable disease process for this particular child. The authors propose this descriptive application of raw performance scores that offers a means to determine neurodevelopmental outcomes in the disorder.

Unravelling the influence of mild traumatic brain injury (MTBI) on cognitive-linguistic processing: a comparative group analysis.

BACKGROUND: Cognitive-linguistic deficits often accompany traumatic brain injury (TBI) and can negatively impact communicative competency. The linguistic sequelae underpinning mild TBI (MTBI) remain largely unexplored in contemporary literature. OBJECTIVES: The present research methods aim to provide group evidence pertaining to the influence of MTBI on linguistic and higher-level language processing. Extrapolating on the findings of recent case reports, it is hypothesized that performance of the MTBI patients will be significantly reduced compared to normal controls performance on the employed high-level linguistic tasks. METHODS: Sixteen patients with MTBI and 16 age- and education-matched normal control participants were assessed using a comprehensive battery of cognitive-linguistic assessments. RESULTS: The results demonstrated statistically significant differences between MTBI and normal control group performance across a number of higher-level linguistic, general cognitive and general language tasks. MTBI group performance was significantly lower than the normal control group on tasks requiring complex lexical semantic operations and memory demands, including: Recall, organization, making inferences, naming and perception/discrimination. CONCLUSIONS: These outcomes confer that post-MTBI, cognitive, high-level language and isolated general language performance (e.g. naming) is significantly reduced in MTBI patients, compared to normal controls. Furthermore, the detailed cognitive-linguistic profile offered provides a necessary direction for the identification of areas of linguistic decline in MTBI and targets for therapeutic intervention of impaired cognitive-linguistic processes to ultimately improve communicative outcomes in MTBI.

The effect of rTMS on auditory processing in adults with chronic, bilateral tinnitus: a placebo-controlled pilot study.

BACKGROUND: On the basis that tinnitus may result from neural hyperactivity in the auditory cortex, researchers have investigated the use of low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) as a potential modulator of this hyperactivity. While these investigations show promise, investigations to date have neglected to consider the possible effect of 1 Hz rTMS on other functions of the auditory cortex of these individuals, such as auditory processing. OBJECTIVE/HYPOTHESIS: This placebo-controlled pilot study aimed to determine whether 1 Hz rTMS applied to the primary auditory cortex (PAC), specifically Brodmann Area 41 (BA41), of adults with chronic, bilateral tinnitus would influence their auditory processing abilities. METHODS: Eight participants with bilateral, chronic tinnitus were randomized to receive a 10-day course of neuronavigationally guided active rTMS (n = 4) or placebo rTMS (n = 4) treatment applied to a focal region of the left PAC (BA41). Participants' auditory processing was measured using Time Compressed Reverberant Speech and three-pair Dichotic Digits (DD). Their tinnitus was measured using the Tinnitus Handicap Inventory (THI) and a psychoacoustic measure of tinnitus perception. All outcome measures were administered at baseline (1 week prior to rTMS), 1 week, 1, 2 and 3 months post-rTMS. RESULTS: All four participants in the active rTMS (A) group, and none of the participants in the sham (placebo) rTMS (S) group, showed improved auditory processing scores at multiple assessment points post-stimulation, with the group differences in median normalized gain scores reaching significance at the 5% level from 1 week or 1 month post-stimulation onwards. Three of the four participants in the active rTMS (A) group, and none of the participants in the sham rTMS (S) group, showed improved tinnitus scores at multiple assessment points post-stimulation, with some of the group differences in median normalized gain scores reaching significance at the 5% level. CONCLUSIONS: The results of this preliminary study suggest that 1 Hz rTMS applied to the PAC (BA41) has the capacity to improve both auditory processing and tinnitus perception in some adults with chronic, bilateral tinnitus.

Language abilities of patients with primary progressive multiple sclerosis: A preliminary group and case investigation.

Language impairments are reported in multiple sclerosis (MS). To date, the majority of studies have evaluated language differences between relapsing-remitting (RR) and chronic progressive (CP) clinical courses. Neurologists have distinguished two progressive courses of MS: primary progressive (PP) MS and secondary progressive (SP) MS. Recent evidence suggests that cognitive performance profiles may provide a means of differentiating between the clinical courses of RR, SP, and PPMS. With this in mind, a deviation of language profiles between sub-types is predicted. The purpose of this study is to profile the language abilities of five participants with PPMS. Five participants with PPMS participated in this investigation. The participants were assessed using the Neurosensory Center Comprehensive Examination for Aphasia (NCCEA), the Boston Naming Test (BNT), and the Test of Language Competence-Expanded (TLC-E). Data analysis consisted of (a) comparison of the total scores achieved by the PPMS participants and a group of 26 age-matched controls on the NCCEA, BNT, and TLC-E, and (b) case studies to individually profile the language abilities of the five participants with PPMS. Comparison of the NCCEA, BNT, and TLC-E total scores of the participants with PPMS and the control group did not indicate significant differences between the two groups. Case-by-case analysis revealed deficits in meta-linguistic abilities in two participants. The results provide preliminary evidence to suggest that, although patients with PPMS may have preserved general language abilities, some individuals may present with mild impairments in high-level linguistic abilities.

Differential phonological awareness skills in children with classic galactosemia: a descriptive study of four cases.

Educational achievement, which for individuals with the metabolic disorder classic galactosemia (GAL) is significantly lower than in the wider population, correlates with self-reported quality of life. Phonological awareness skills underpin the development of literacy, and although literacy is a key contributor to successful academic outcomes, no study to date has investigated phonological awareness skills in children with GAL. This study investigated phonological awareness (PA) in four school-aged children with the disorder, two of whom were siblings. Age range for the children was 7 years 7 months to 9 years 2 months. Each child was assessed with the Phonological Awareness criterion-referenced subtest from the Clinical Evaluation of Language Fundamentals-Fourth Edition. Included in the data for analysis was each child's performance measures obtained from their most recent assessment of cognitive and lexical development. A number of descriptive analyses were undertaken on the data. One child, who met her age criterion for PA, had cognitive and lexical development skills in the average range. The remaining three children failed to meet their age criteria. Although these three children presented with clinically similar cognitive and lexical development skills, disparate PA skills were identified. The PA skills of one of the sibling pair were notably more advanced than his older sibling. The limitations of relying on behavioural test results in children with GAL to predict those most at risk of reduced skill development are discussed in terms future research directions.

Differential language trajectories following treatment for pediatric posterior fossa tumor: an investigation of four cases.

Up to 85% of children treated for brain tumor survive beyond five years; hence optimizing quality of life in survivorship has become a priority. As multiple factors contribute to the heterogeneity of neurocognitive and language outcomes for individual children following treatment, a means of monitoring subsequent development is needed for the individual child, particularly when pre-morbid performance indices are not available. The current study investigated the use of developmental language trajectories as a means of monitoring language development subsequent to treatment for tumors located within the posterior fossa. The language skills of four children treated for posterior fossa tumor (PFT) were monitored over time (range of monitoring: 2-6 years) and the resultant trajectories were plotted against the trajectories based on tests' normative data as well as the trajectories of control children drawn from each child's local community. Each child's trajectory was considered in terms of age-appropriate developmental gains and discussed regarding the need for ongoing clinical monitoring of emerging, developing or established language skills. The study's findings highlight the heterogeneity of language outcomes following PFT. The utility of the application of developmental trajectories for the provision of individualized post-treatment support is discussed.

Longitudinal language outcomes following intrathecal chemotherapy for acute lymphoblastic leukaemia.

Intrathecal chemotherapy (ITC) is the treatment option for acute lymphoblastic leukaemia (ALL). Neurocognitive deficits have been described following ITC, but language status post-treatment is yet to be clarified. This study examined the language skills of nine children following ITC for ALL (mean age 7;8 years and 3;2 years post-diagnosis at baseline measurement) and nine age- and sex-matched controls, at baseline then 2 years later, using a battery of tests assessing general language skills. An assessment of cognitively-demanding high level language skills was undertaken on a sub-group of the children (n =12). Statistical analysis revealed no significant difference between children treated with ITC and controls when comparing change in performance scores from baseline measurement to 2 years post-baseline measurement. Descriptive analysis of three of the ALL participants in the Intermediate Stage survivorship at language re-assessment indicated no clinically-significant change in performance over 2 years for all measures except receptive language skills, which improved over the time for two of the children. As language skills continue to develop into late adolescence, the need for the monitoring of language abilities of children treated at a young age with ITC as they enter the Intermediate and Late Stages of survivorship is discussed.

Non-invasive brain stimulation: a new frontier in the treatment of neurogenic speech-language disorders.

There is a growing body of evidence to support the use of non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) for the treatment of acquired speech and language disorders. The aim of the present paper is to review evidence to support the use of these procedures in the treatment of aphasia and dysarthria. Both TMS and tDCS are described in terms of their underlying principles and biophysics and their relative advantages and disadvantages for rehabilitation of acquired neurogenic communication disorders. Several studies have documented positive effects of inhibitory repetitive TMS (rTMS) to right Broca's area homologue on language recovery in non-fluent aphasia post-stroke. Improved language outcomes subsequent to high frequency rTMS applied to the lesioned hemisphere have also been documented. Similarly, therapeutic benefits have also been reported following tDCS, although the findings are less consistent than is the case with rTMS. Improved articulatory function and speech intelligibility has been noted in response to stimulation with excitatory rTMS in Parkinson's disease. It is suggested that the use of brain stimulation techniques in combination with more traditional therapies may represent the most innovative future approach to the treatment of acquired communication disorders.

Lingual kinematics during rapid syllable repetition in Parkinson's disease.

BACKGROUND: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). AIMS: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric speakers with PD (DPD), non-dysarthric speakers with PD (NDPD) and a group of healthy controls. METHODS & PROCEDURES: Electromagnetic articulography was used to record tongue-tip and tongue-back movement in five DPD and five NDPD participants during rapid repetition of /ta/and /ka/syllables, and matched with six healthy controls. OUTCOMES & RESULTS: Results revealed significant between-group differences for most of the kinematic parameters measured but comparable rapid syllable repetition rates. Post-hoc analyses indicated that the DPD participants, when compared with the NDPD participants, had similar range but prolonged duration of lingual movement. The DPD and NDPD participants had primarily increased range and prolonged duration of lingual movement accompanied by increased speed parameters, when compared with healthy controls. CONCLUSIONS & IMPLICATIONS: The findings of the present study contradict theories that suggest that the clinical features of hypokinetic dysarthria, including articulatory imprecision, are the outcome of restrictions in the range of movement of the muscles of the articulators. The observed prolonged duration of lingual movement in PD may plausibly be due to the observed increased range of lingual movement rather than slowness of lingual movement.

Longitudinal change in dysarthria associated with Friedreich ataxia: a potential clinical endpoint.

CNS functions that show change across short periods of time are particularly useful clinical endpoints for Friedreich ataxia. This study determined whether there is measurable acoustical change in the dysarthria associated with Friedreich ataxia across yearly intervals. A total of 29 participants diagnosed with Friedreich ataxia were recorded across 4 years at yearly intervals. A repeated measures ANOVA was used to determine which acoustic measures differed across time, and pairwise t tests were used to assess the consistency of the change across the time intervals. The relationship between the identified measures with perceptual severity was assessed with stepwise regression. Significant longitudinal change was observed with four measures that relate to the utterance duration and spectral changes in utterances. The spectral measures consistently detected change across time intervals of two or more years. The four measures combined moderately predicted perceptual severity. Together, the results implicate longitudinal change in speaking rate and utterance duration. Changes in speech associated with Friedreich ataxia can be measured across intervals of 2 years and therefore show rich potential for monitoring disease progression and therapy outcomes.

Amount of kinematic feedback affects learning of speech motor skills.

Knowledge of Performance (KP) feedback, such as biofeedback or kinematic feedback, is used to provide information on the nature and quality of movement responses for the purpose of guiding active learning or rehabilitation of motor skills. It has been proposed that KP feedback may interfere with long-term learning when provided throughout training. Here, twelve healthy English-speaking adults were trained to produce a trilled Russian [r] in words with KP kinematic feedback using electropalatography (EPG) and without KP (noKP). Five one-hour training sessions were provided over one week with testing pretraining and one day and one week posttraining. No group differences were found at pretraining or one day post training for production accuracy. A group by time interaction supported the hypothesis that providing kinematic feedback continually during skill acquisition interferes with retention.

Effect of speech rate manipulations on articulatory dynamics in severe traumatic brain injury: an EMA and EPG study.

BACKGROUND: Manipulation of speech rate forms an integral part of the treatment of dysarthria and the effects of changes in speech rate on articulatory dynamics in persons with traumatic brain injury (TBI) is poorly documented. OBJECTIVE: To determine the effects of manipulations of speech rate (habitual vs fast) on lingual kinematics and tongue-to-palate contacts in adult speakers with severe TBI and matched normal controls. MATERIALS AND METHODS: Six adults with severe TBI and five matched non-neurologically impaired controls underwent testing of their articulatory function using electromagnetic articulography (EMA) and electropalatography (EPG). RESULTS: The results demonstrated that the TBI and control groups selected different strategies for increasing speech rate, with the TBI group showing an increase in articulatory effort estimated from an increase in maximum velocity and maximum acceleration/deceleration of tongue movement when speaking at the fast rate. The control group demonstrated no effects of a fast speech rate on articulatory kinematics for sentence productions. CONCLUSIONS: When speaking at a fast rate, individuals with severe TBI appear to use greater articulatory effort, possibly to preserve the distinctiveness of phonetic segments in order to avoid articulatory undershoot. In contrast, control subjects show a greater economy of effort when speaking at a fast rate, possibly to preserve articulatory precision.

Indices of language outcome 11 years after intrathecal chemotherapy for acute lymphoblastic leukemia: a sibling case-control study.

Studies are emerging that suggest that major language indices do not differentiate children treated for acute lymphoblastic leukemia (ALL) with risk-adapted intrathecal chemotherapy (ITC) from control children matched on age, gender, and educational level. No study to date has controlled for cognitive environment, an important variable influencing language achievement and outcome. This case-control study applies the deconfounding principle by using a sibling as a control to investigate language outcomes in a male child 11 years after administration of ITC for ALL at the age of 2 years 3 months. A comprehensive behavioral language test battery failed to differentiate the siblings on current language performance when descriptively compared, but neurophysiological assessment revealed that the ITC-treated child required more time and elicited a smaller N400 component compared to his sibling during picture-word matching. The findings suggest that in the absence of pretreatment performance indices, comparison with sibling achievement may supplement what is known on posttreatment language skill development drawn from comparative studies using children matched on age, sex, and educational level drawn from the community. The study's findings offer pilot data of language outcomes following ITC beyond the early stage of survivorship. The benefits and limitations of using siblings in research where the cognitive environment is known to make an important contribution to skill development are discussed.

Differentiating profiles of speech impairments in Friedreich's ataxia: a perceptual and instrumental approach.

BACKGROUND: The speech disorder associated with Friedreich's ataxia (FRDA) is classically described as ataxic dysarthria. However, variable neuropathology beyond the cerebellum, which may include the corticospinal and corticobulbar tracts, means that the dysarthria can be mixed rather than a pure ataxic dysarthria. AIMS: To characterize physiological features of the dysarthria associated with FRDA and identify differential patterns of deviation that may occur across the subsystems of the speech-production mechanism in a series of seven case studies. METHODS & PROCEDURES: The assessment battery included a perceptual analysis of a speech sample using an interval rating scale, and a range of instrumental measures to investigate the respiratory, laryngeal, velopharyngeal and articulatory systems. OUTCOMES & RESULTS: The results demonstrated the variability that exists in the dysarthria associated with FRDA, highlighting the existence of differential profiles of speech impairment. A particular distinction was observed between the presence of hypernasality and phonatory dysfunction, as evidenced by the instrumental results. CONCLUSIONS & IMPLICATIONS: The distinct profiles of dysarthria associated with FRDA indicate that approaches that address multiple subsystems are necessary for the accurate characterization and quantification of the motor speech disorder. Further research is required to investigate the decline in speech function as the disease progresses, as changes in speech function over time may be a good indicator of neurological decline in FRDA.

Developmental changes in the variability of tongue and lip movements during speech from childhood to adulthood: an EMA study.

This study investigated the developmental variability of lip and tongue movement in 48 children and adults. Motion of the tongue-tip, tongue-body and lower lip was recorded using electromagnetic articulography during productions of sentences containing /t/, /s/, /l/, /k/ and /p/. Four groups of speakers participated in the study: (1) aged 6-7 years; (2) 8-11 years; (3) 12-17 years; and (4) adults. The variation in distance, duration, speed, acceleration and deceleration of the articulators during single open-close speech movements was analysed, and the stability of multiple movement sequences was examined using the spatiotemporal index. The experimental findings revealed a gradual developmental progression from 6 years to adulthood. At adolescence, speakers continued to exhibit significantly more variable speech motor output compared to adult speakers. The observed developmental pattern suggests that attenuated, but important, changes in the speech motor system occurs from mid-childhood, through adolescence, to adulthood.

Improved receptive and expressive language abilities in nonfluent aphasic stroke patients after application of rTMS: an open protocol case series.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has been identified as a potentially valuable tool for the rehabilitation of language impairment after left hemisphere (LH) stroke, in populations of persons with chronic aphasia. Applied to a homologue to Broca's area, rTMS is posited to modulate bilateral language networks, promoting measurable behavioral language change, in accordance with theories of transcallosal disinhibition arising from the damaged LH. OBJECTIVE/HYPOTHESIS: The current investigation is an open-label study, presenting detailed case and group presentations on a population of seven nonfluent aphasic participants. Behavioral language performance is presented on expressive and receptive language measures up to 8 months after a 10-day protocol of 1 Hz stimulation. This research aims to provide longitudinal behavioral language outcomes for persons with aphasia, subsequent to rTMS and supplement previous studies to inform the clinical efficacy of rTMS. RESULTS: In accordance with previous investigations, significant improvements in picture naming, spontaneous elicited speech and auditory comprehension were found. Time of testing was identified as a significant main effect. Significant improvements in picture naming accuracy and decreases in picture naming latency were also identified. The results demonstrate sustained language improvements up to 8 months subsequent to TMS application. CONCLUSIONS: The results of this investigation are consistent with the findings of previous research studies, reporting behavioral language changes after rTMS in nonfluent aphasia. Additional evidence is provided to demonstrate that rTMS may facilitate retrieval mechanisms involved in picture naming.