Mélanie Langlois

Mattis Dementia Rating Scale 2 Screening for MCI and Dementia

Identifying patients at higher risk of developing dementia is important. The usefulness of the Mattis Dementia Rating scale-Second Edition (MDRS-2) to detect and differentiate between patients with amnestic mild cognitive impairment (A-MCI), Parkinson’s disease and MCI (PD-MCI), PD with dementia (PDD), and Alzheimer’s disease (AD) was investigated. In all, 22 healthy controls (HC), 22 A-MCI, 22 PD-MCI, 16 PDD, and 22 AD patients were evaluated using an extensive neuropsychological battery, including the MDRS-2. The MDRS-2 total standardized score detected all groups of patients. The dementia groups performed worse than HC on the 5 MDRS-2 subscales. Alzheimer’s disease patients scored higher than PDD on MDRS-2 conceptualization and lower on memory. Healthy controls were better than PD-MCI on MDRS-2 initiation/perseveration and memory and better than A-MCI on memory. No difference was found between the MCI groups. The MDRS-2 is a suitable short scale for MCI and dementia screening but is not specific enough to differentiate between A-MCI and PD-MCI.

Clinical Validity of the Mattis Dementia Rating Scale-2 in Parkinson Disease With MCI and Dementia:

The utility of the Mattis Dementia Rating Scale 2 (MDRS-2) in screening for dementia in Parkinson disease (PD) is well documented. However, little is known about its sensitivity to mild cognitive impairment in PD (PD-MCI). This study sought to document the validity of the MDRS-2 for diagnoses of PD-MCI and dementia in PD (PDD). Twenty-two healthy controls (HCs), 22 PD-MCI, and 16 PDD were compared on each MDRS-2 subscales and MDRS-2 total standard scores. Patients with PDD performed significantly worse than the other groups (all Ps < .05) on the MDRS-2 total and on all subscales, except attention. PD-MCI had significant lower scores than HCs on the MDRS-2 total and on initiation/perseveration and memory subscales. The optimal cutoff score for PD-MCI diagnosis was ≤ 140/144 and ≤ 132/144 for PDD. These findings suggest that MDRS-2 is a useful tool to identify dementia but that there might be a ceiling effect in the MDRS-2 cutoff score to diagnose MCI in PD.

Impact of the LSVT on vowel articulation and coarticulation in Parkinson’s disease

Abstract The purpose of this study was to investigate the impact of the Lee Silverman Voice Treatment (LSVT®) on vowel articulation and consonant–vowel (C–V) coarticulation in dysarthric speakers with Parkinson’s disease (PD). Nine Quebec French speakers diagnosed with idiopathic PD underwent the LSVT®. Speech characteristics were compared before and after treatment. Vowel articulation was measured using acoustic vowel space and calculated with the first (F1) and second formant (F2) of the vowels /i/, /u/ and /a/. C–V coarticulation was measured using locus equations, an acoustic metric based on the F2 transitions within vowels in relation to the preceding consonant. The relationship between these variables, speech loudness and vowel duration was also analysed. Results showed that vowel contrast increased in F1/F2 acoustic space after administration of the LSVT®. This improvement was associated with the gain in speech loudness and longer vowel duration. C–V coarticulation patterns between consonant contexts showed greater distinctiveness after the treatment. This improvement was associated with the gain in speech loudness only. These results support the conclusions of previous studies investigating the relationship between the LSVT®, speech loudness and articulation in PD. These results expand clinical understanding of the treatment and indicate that loud speech changes C–V coarticulation patterns. Clinical applications and theoretical considerations are discussed.

Changes in Vowel Articulation with Subthalamic Nucleus Deep Brain Stimulation in Dysarthric Speakers with Parkinson's Disease

Purpose. To investigate changes in vowel articulation with the electrical deep brain stimulation (DBS) of the subthalamic nucleus (STN) in dysarthric speakers with Parkinsons disease (PD). Methods. Eight Quebec-French speakers diagnosed with idiopathic PD who had undergone STN DBS were evaluated ON-stimulation and OFF-stimulation (1 hour after DBS was turned off). Vowel articulation was compared ON-simulation versus OFF-stimulation using acoustic vowel space and formant centralization ratio, calculated with the first (F1) and second formant (F2) of the vowels /i/, /u/, and /a/. The impact of the preceding consonant context on articulation, which represents a measure of coarticulation, was also analyzed as a function of the stimulation state. Results. Maximum vowel articulation increased during ON-stimulation. Analyses also indicate that vowel articulation was modulated by the consonant context but this relationship did not change with STN DBS. Conclusions. Results suggest that STN DBS may improve articulation in dysarthric speakers with PD, in terms of range of movement. Optimization of the electrical parameters for each patient is important and may lead to improvement in speech fine motor control. However, the impact on overall speech intelligibility may still be small. Clinical considerations are discussed and new research avenues are suggested.

The Role of Basal Ganglia in Language Production: Evidence from Parkinson's Disease

According to the dominant view in the literature, basal ganglia do not play a direct role in language but are involved in cognitive control required by linguistic and non-linguistic processing. In Parkinsons disease, basal ganglia impairment leads to motor symptoms and language deficits; those affecting the production of verbs have been frequently explored. According to a controversial theory, basal ganglia play a specific role in the conjugation of regular verbs as compared to irregular verbs. We report the results of 15 patients with Parkinsons disease in experimental conjugation tasks. They performed below healthy controls but their performance did not differ for regular and irregular verbs. These results confirm that basal ganglia are involved in language processing but do not play a specific role in verb production.

The effects of subthalamic deep brain stimulation on metaphor comprehension and language abilities in Parkinson’s disease

The effects of subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinsons disease (PD) on different language abilities are still controversial and its impact on high-level language abilities such as metaphor comprehension has been overlooked. The aim of this study was to determine the effects of STN electrical stimulation on metaphor comprehension and language abilities such as lexical and semantic capacities. Eight PD individuals with bilateral STN-DBS were first evaluated OFF-DBS and, at least seven weeks later, ON-DBS. Performance on metaphor comprehension, lexical decision, word association and verbal fluency tasks were compared ON and OFF-DBS in addition to motor symptoms evaluation. STN stimulation had a significant beneficial effect on motor symptoms in PD. However, this stimulation did not have any effect on metaphor comprehension or any other cognitive ability evaluated in this study. These outcomes suggest that STN stimulation may have dissociable effects on motor and language functions.

Transient executive dysfunction following STNDBS in Parkinson's disease.

Deep brain stimulation (DBS) is an alternative treatment for patients with advanced Parkinson’s disease (PD) inadequately or insufficiently controlled with pharmacological treatments. It consists of implanting an electrode in a specific subcortical region to modulate its electrical activity. The structure most often targeted in PD is the subthalamic nucleus (STN). Chronic high frequency stimulation of the STN helps to reduce tremor, dyskynesia and medication doses, and its effectiveness is now well established1. However, there is also a risk that STN-DBS could lead to cognitive side effects but evidence of this is scarce and controversial. Some studies showed minimal influence of STN-DBS on cognition2, while others reported decline3,4 in cognitive efficiency in similar (verbal fluency, executive functions and working memory) or different domains (e.g. improved vs. reduced performance on procedural and declarative memory respectively5). The purpose of this study was to characterize the cognitive performance of PD subjects having undergone bilateral STNDBS and to identify shortand longer-term effects on various domains of cognition.

Articulatory Changes in Vowel Production following STN DBS and Levodopa Intake in Parkinson’s Disease

Purpose. To investigate the impact of deep brain stimulation of the subthalamic nucleus (STN DBS) and levodopa intake on vowel articulation in dysarthric speakers with Parkinsons disease (PD). Methods. Vowel articulation was assessed in seven Quebec French speakers diagnosed with idiopathic PD who underwent STN DBS. Assessments were conducted on- and off-medication, first prior to surgery and then 1 year later. All recordings were made on-stimulation. Vowel articulation was measured using acoustic vowel space and formant centralization ratio. Results. Compared to the period before surgery, vowel articulation was reduced after surgery when patients were off-medication, while it was better on-medication. The impact of levodopa intake on vowel articulation changed with STN DBS: before surgery, levodopa impaired articulation, while it no longer had a negative effect after surgery. Conclusions. These results indicate that while STN DBS could lead to a direct deterioration in articulation, it may indirectly improve it by reducing the levodopa dose required to manage motor symptoms. These findings suggest that, with respect to speech production, STN DBS and levodopa intake cannot be investigated separately because the two are intrinsically linked. Along with motor symptoms, speech production should be considered when optimizing therapeutic management of patients with PD.

Les déficits de compréhension du langage non littéral dans la maladie de Parkinson sont-ils liés à un déficit de la théorie de l’esprit ?

Theory of mind (TOM), i.e. the capacity to attribute mental states to oneself and others, would be impaired in Parkinsons disease (PD). Nonliteral language (NLL) comprehension would also be impaired in this disease. The goal of this study was to verify the presence of an association between the TOM and NLL comprehension deficits. We assessed 15 individuals in the early stages of PD and 17 healthy controls (HC), comparable on gender, age and education. Each subject completed a TOM evaluation task and a NLL task (i.e. metaphor comprehension). They also completed executive functioning (mental flexibility, inhibition and working memory) evaluation tasks. Our results showed that patients with PD had significant difficulties in the TOM and NLL comprehension tasks compared to HC participants. A significant relationship was found between TOM and NLL comprehension results. Moreover, NLL scores were associated with a task evaluating mental flexibility. Thus, PD might cause both TOM and NLL comprehension deficit even in the early stages of the disease. Our results showed that there would be a close relationship between TOM and NLL in people with PD.

The influence of vascular risk factors on cognitive function in early Parkinson's disease

Hypertension, dyslipidemia, diabetes, and obesity are well‐established risk factors for cognitive impairment and dementia in older adults. In contrast, previous studies that have assessed the impact of vascular risk factors (VRFs) on cognition in Parkinsons disease (PD) have had methodological limitations and reported conflicting findings. We address this question in a large well‐characterized cohort of de novo PD patients.