Dysarthria and orofacial apraxia in corticobasal degeneration

Clinicopathologic and Neuroimaging Correlations of Nonverbal Oral Apraxia in Patients With Neurodegenerative Disease

BACKGROUND AND OBJECTIVES

Nonverbal oral apraxia (NVOA) is the inability to plan, sequence, and execute voluntary oromotor movements in the absence of weakness. In the context of neurodegenerative disease, it remains unclear whether it is linked to a specific underlying pathologic, clinical, or neuroimaging finding. Thus, we aimed to assess the clinicopathologic and neuroimaging associations of NVOA.

METHODS

We conducted a retrospective study of autopsy-confirmed patients previously assessed through an NVOA evaluation tool with a previously published cutpoint to screen for NVOA. We compared demographic and clinical characteristics and postmortem pathology between those who developed NVOA and those who did not. We also compared clinicopathologic characteristics in mild vs greater than mild NVOA and early vs late-emerging NVOA. SPM12 was used to assess patterns of gray matter loss in NVOA vs non-NVOA with age and sex included as covariates.

RESULTS

A total of 104 patients (median age at symptom onset 63 years, 43% female) were included in the study. 63 (60.6%) developed NVOA. NVOA appeared at a median of 4.3 years from symptom onset. 29% developed NVOA within the first 3 years. Primary progressive apraxia of speech and the nonfluent variant of primary progressive aphasia were the most common baseline diagnoses in the NVOA group while progressive supranuclear palsy (PSP) syndrome and logopenic progressive aphasia (LPA) were the most common in patients without NVOA. Atrophy of the left lateral and medial posterior frontal cortex was related to NVOA. The most common pathologies associated with NVOA were PSP (36.5%) and corticobasal degeneration (CBD) (33.3%). In patients without NVOA, PSP (26.8%) and other pathologies (26.8%) were the most frequent. 11% of patients with NVOA had persistently mild NVOA and were more likely to have baseline diagnoses of LPA, PSP syndrome, or semantic dementia. The most frequent pathologies in this group were Alzheimer disease and PSP. The pathologic associations of greater than mild NVOA were CBD and PSP.

DISCUSSION

NVOA is present in several clinical syndromes. It is most associated with PSP and CBD. NVOA is a manifestation of left lateral and medial posterior frontal cortex damage rather than a particular pathology.

The Discourse Profile in Corticobasal Syndrome: A Comprehensive Clinical and Biomarker Approach

The aim of this study was to characterize the oral discourse of CBS patients and to verify whether measures obtained during a semi-spontaneous speech production could differentiate CBS patients from controls. A second goal was to compare the performance of patients with CBS probably due to Alzheimer's disease (CBS-AD) pathology and CBS not related to AD (CBS-non-AD) in the same measures, based on the brain metabolic status (FDG-PET) and in the presence of amyloid deposition (amyloid-PET). Results showed that CBS patients were significantly different from controls in speech rate, lexical level, informativeness, and syntactic complexity. Discursive measures did not differentiate CBS-AD from CBS-non-AD. However, CBS-AD displayed more lexical-semantic impairments than controls, a profile that is frequently reported in patients with clinical AD and the logopenic variant of primary progressive aphasia (lvPPA). CBS-non-AD presented mainly with impairments related to motor speech disorders and syntactic complexity, as seen in the non-fluent variant of PPA.

Language impairment in progressive supranuclear palsy and corticobasal syndrome

Although commonly known as movement disorders, progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) may present with changes in speech and language alongside or even before motor symptoms. The differential diagnosis of these two disorders can be challenging, especially in the early stages. Here we review their impact on speech and language. We discuss the neurobiological and clinical-phenomenological overlap of PSP and CBS with each other, and with other disorders including non-fluent agrammatic primary progressive aphasia and primary progressive apraxia of speech. Because language impairment is often an early and persistent problem in CBS and PSP, there is a need for improved methods for language screening in primary and secondary care, and more detailed language assessments in tertiary healthcare settings. Improved language assessment may aid differential diagnosis as well as inform clinical management decisions.

Swallowing disturbances in the corticobasal syndrome

OBJECTIVES

To determine the characteristics of swallowing and speech disturbances in patients with corticobasal syndrome (CBS) compared to healthy controls, and whether a subjective swallowing questionnaire, the NIH-Speech Pathology swallowing questionnaire (NIH-SQ), can predict swallowing impairment.

METHODS

Twenty-four consecutive CBS patients underwent a swallowing assessment comprised of the NIH-SQ, ultrasound swallow study (US) and modified barium swallow (MBS) study. Healthy controls (n = 28) completed the NIH-SQ and the US.

RESULTS

Ninety-six percent of the patients with CBS reported at least one complaint in the NIH-SQ, 59% had abnormal dry swallow duration and 10% abnormal wet swallow duration. Twenty-three patients with CBS had some abnormality on the MBS. The MBS category "piecemeal deglutition" (excessive lingual gestures causing multiple swallows required to clear a single bolus) was characteristic of CBS patients. No aspiration was detected. No NIH-SQ cutoff score or combination of subjective complaints predicted an abnormal MBS. Fifty-two percent of the patients had speech apraxia.

CONCLUSIONS

Swallowing and speech disturbances are common in patients with CBS and differ from those previously reported in patients with PSP syndrome. Piecemeal deglutition and speech apraxia are characteristic features of our CBS patients. Although the NIH-SQ cannot predict the results of the more objective MBS in this population, it characterizes the patients' major subjective swallowing complaints.

The c.429_452 duplication of the ARX gene: a unique developmental-model of limb kinetic apraxia

Background

The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Intellectual Disability without brain malformation. While in certain cases c.429_452dup24 has been associated with specific clinical patterns such as Partington syndrome, the consequence of this mutation has been also often classified as “non-specific Intellectual Disability”. The present work aims at a more precise description of the clinical features linked to the c.429_452dup24 mutation.

Methods

We clinically reviewed all affected patients identified in France over a five-year period, i.e. 27 patients from 12 different families. Detailed cognitive, behavioural, and motor evaluation, as well as standardized videotaped assessments of oro-lingual and gestural praxis, were performed. In a sub-group of 13 ARX patients, kinematic and MRI studies were further accomplished to better characterize the motor impairment prevalent in the ARX patients group. To ensure that data were specific to the ARX gene mutation and did not result from low-cognitive functioning per se, a group of 27 age- and IQ-matched Down syndrome patients served as control.

Results

Neuropsychological and motor assessment indicated that the c.429_452dup24 mutation constitutes a recognizable clinical syndrome: ARX patients exhibiting Intellectual Disability, without primary motor impairment, but with a very specific upper limb distal motor apraxia associated with a pathognomonic hand-grip. Patients affected with the so-called Partington syndrome, which involves major hand dystonia and orolingual apraxia, exhibit the most severe symptoms of the disorder. The particular “reach and grip” impairment which was observed in all ARX patients, but not in Down syndrome patients, was further characterized by the kinematic data: (i) loss of preference for the index finger when gripping an object, (ii) major impairment of fourth finger deftness, and (iii) a lack of pronation movements. This lack of distal movement coordination exhibited by ARX patients is associated with the loss of independent digital dexterity and is similar to the distortion of individual finger movements and posture observed in Limb Kinetic Apraxia.

Conclusion

These findings suggest that the ARX c.429_452dup24 mutation may be a developmental model for Limb Kinetic Apraxia.

Apraxia in progressive nonfluent aphasia

The clinical and neuroanatomical correlates of specific apraxias in neurodegenerative disease are not well understood. Here we addressed this issue in progressive nonfluent aphasia (PNFA), a canonical subtype of frontotemporal lobar degeneration that has been consistently associated with apraxia of speech (AOS) and in some cases orofacial apraxia, limb apraxia and/or parkinsonism. Sixteen patients with PNFA according to current consensus criteria were studied. Three patients had a corticobasal syndrome (CBS) and two a progressive supranuclear palsy (PSP) syndrome. Speech, orofacial and limb praxis functions were assessed using the Apraxia Battery for Adults-2 and a voxel-based morphometry (VBM) analysis was conducted on brain MRI scans from the patient cohort in order to identify neuroanatomical correlates. All patients had AOS based on reduced diadochokinetic rate, 69% of cases had an abnormal orofacial apraxia score and 44% of cases (including the three CBS cases and one case with PSP) had an abnormal limb apraxia score. Severity of orofacial apraxia (but not AOS or limb apraxia) correlated with estimated clinical disease duration. The VBM analysis identified distinct neuroanatomical bases for each form of apraxia: the severity of AOS correlated with left posterior inferior frontal lobe atrophy; orofacial apraxia with left middle frontal, premotor and supplementary motor cortical atrophy; and limb apraxia with left inferior parietal lobe atrophy. Our findings show that apraxia of various kinds can be a clinical issue in PNFA and demonstrate that specific apraxias are clinically and anatomically dissociable within this population of patients.

Apraxia of speech and nonfluent aphasia: a new clinical marker for corticobasal degeneration and progressive supranuclear palsy

PURPOSE OF REVIEW

To highlight the fact that patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) can sometimes present with a progressive apraxia of speech, nonfluent aphasia, or a combination of the two disorders.

RECENT FINDINGS

Corticobasal degeneration and PSP are neurodegenerative diseases characterized by neuronal loss and gliosis in cardinal brain regions, as well as the abnormal deposition of the microtubule associated protein tau in cell bodies and cell processes. The typical presenting features of CBD and PSP are akinesia and rigidity that are levodopa unresponsive, although there has been evidence that both diseases, moreso CBD, can present with a dementia syndrome. Recent clinicopathological studies have now also demonstrated that a subset of patients with CBD and PSP present with a progressive apraxia of speech, nonfluent aphasia, or a combination of the two disorders.

SUMMARY

Presenting features of progressive apraxia of speech or nonfluent aphasia are strongly associated with a diagnosis of CBD, PSP, or both.

Common neural substrates support speech and non-speech vocal tract gestures

The issue of whether speech is supported by the same neural substrates as non-speech vocal tract gestures has been contentious. In this fMRI study we tested whether producing non-speech vocal tract gestures in humans shares the same functional neuroanatomy as non-sense speech syllables. Production of non-speech vocal tract gestures, devoid of phonological content but similar to speech in that they had familiar acoustic and somatosensory targets, was compared to the production of speech syllables without meaning. Brain activation related to overt production was captured with BOLD fMRI using a sparse sampling design for both conditions. Speech and non-speech were compared using voxel-wise whole brain analyses, and ROI analyses focused on frontal and temporoparietal structures previously reported to support speech production. Results showed substantial activation overlap between speech and non-speech function in regions. Although non-speech gesture production showed greater extent and amplitude of activation in the regions examined, both speech and non-speech showed comparable left laterality in activation for both target perception and production. These findings posit a more general role of the previously proposed "auditory dorsal stream" in the left hemisphere--to support the production of vocal tract gestures that are not limited to speech processing.

Treatment of dementia in parkinsonian syndromes with cholinesterase inhibitors

In Parkinsonian syndromes behavioural symptoms and dementia can be even more debilitating than motor symptoms and are an important predictor for nursing home placement and mortality. Neuropathologically, dementia seems to be primarily related to cortical changes rather than to subcortical alterations. Concerning neurotransmitter systems, the cholinergic system has been proposed to play a key role in cognitive disturbances. Based on studies with patients with Alzheimer disease, the application of cholinesterase inhibitors is vividly discussed also for dementia associated with parkinsonian syndromes. This review focuses on the specific symptoms of dementia in different parkinsonian syndromes and critically questions the effect of cholinergic treatment on cognitive functions in patients with extrapyramidal syndromes and dementia. There is evidence that medication with some cholinesterase inhibitors can enhance cognition as well as activities of daily living in dementia with Parkinson's disease and seems to reduce behavioural disturbances in both dementia with Parkinson's disease and dementia with Lewy bodies. The effect of treatment with cholinesterase inhibitors in progressive supranuclear palsy and corticobasal degeneration warrants carefully designed studies including a sufficient number of patients and symptom-adopted dementia scales.

GABAergic output of the basal ganglia

Using GABAergic outputs from the SNr or GP(i), the basal ganglia exert inhibitory control over several motor areas in the brainstem which in turn control the central pattern generators for the basic motor repertoire including eye-head orientation, locomotion, mouth movements, and vocalization. These movements are by default kept suppressed by tonic rapid firing of SNr/GP(i) neurons, but can be released by a selective removal of the tonic inhibition. Derangement of the SNr/GP(i) outputs leads to either an inability to initiate movements (akinesia) or an inability to suppress movements (involuntary movements). Although the spatio-temporal patterns of individual movements are largely innate and fixed, it is essential for survival to select appropriate movements and arrange them in an appropriate order depending on the context, and this is what the basal ganglia presumably do. To achieve such a goal, however, the basal ganglia need to be trained to optimize their outputs with the aid of cortical inputs carrying sensorimotor and cognitive information and dopaminergic inputs carrying reward-related information. The basal ganglia output to the thalamus, which is particularly developed in primates, provides the basal ganglia with an advanced ability to organize behavior by including the motor skill mechanisms in which new movement patterns can be created by practice. To summarize, an essential function of the basal ganglia is to select, sort, and integrate innate movements and learned movements, together with cognitive and emotional mental operations, to achieve purposeful behaviors. Intricate hand-finger movements do not occur in isolation; they are always associated with appropriate motor sets, such as eye-head orientation and posture.

Progressive oculo-orofacial-speech apraxia (POOSA)

A loss of speech can be related to disorders of the motor units (paresis), language deficits (aphasia), or speech programming deficits (apraxia of speech). Although apraxia of speech has been reported to be associated with degenerative diseases, we observed a patient with a unique constellation of signs that included apraxia of speech, oculo-orofacial apraxia and a supranuclear ophthalmoplegia in the absence of extrapyramidal (Parkinsonian) signs. Post-mortem examination revealed a loss of neurons in the frontal and temporal regions, but there was also a marked loss of neurons and astrogliosis in the caudate, claustrum, globus pallidus, substantia nigra, and loss of axons in the anterior cerebral peduncles. This patient's clinical presentation and the pathological correlates suggest that he might have suffered with a distinct disorder we call progressive oculo-orofacial-speech apraxia or POOSA.

Philosophy of research in motor speech disorders

The primary objective of this position paper is to assess the theoretical and empirical support that exists for the Mayo Clinic view of motor speech disorders in general, and for oromotor, nonverbal tasks as a window to speech production processes in particular. Literature both in support of and against the Mayo clinic view and the associated use of oromotor, nonverbal tasks, is reviewed, along with literature from normal speech production and neurophysiology. This literature is organized and analysed to show that theoretical and experimental support for the Mayo view is weak at best, and that the frequent appeal to oromotor, nonverbal tasks is misguided. We conclude that studies of speech production in motor speech disorders, rather than oromotor nonverbal control or of neurological signs, is the correct approach for advancing the field.

The place of perceptual analysis of dysarthria in the differential diagnosis of corticobasal degeneration and Parkinson's disease

OBJECTIVE

To characterize the dysarthria in patients with corticobasal degeneration (CBD) and determine if analysis of speech in isolation helps to distinguish CBD patients from patients with Parkinson's disease (PD).

METHODS

60 subjects were assessed by means of perceptual analysis of speech: 15 patients with CBD, 15 patients with PD and 30 control subjects. A detailed profile was furnished with the help of 33 perceptual items. A global perceptual approach was used to classify patients by judges blind to the medical diagnosis. Rating scales were adapted to quantify the degree of spasticity and hypokinesia in the speech of each patient.

RESULTS

Dysarthria was frequent in CBD even though it remained mild for a long period of time. Group analysis revealed the importance of temporal errors of speech control in CBD patients while voice disturbances were most frequent in PD patients. However, attempts to classify patients according to global perceptual analysis remained below a reasonable level of clinical acceptability. Finally, even though the widespread neuropathological changes suggest that deviant speech dimensions of several types of dysarthria might be found in CBD, evidence for a mixed dysarthria with presence of spastic elements could not be established.

CONCLUSION

The findings support the view that even though perceptual analysis is mandatory in the management of dysarthric patients, it does not help in the clinical differential diagnosis of CBD.

Apraxia in movement disorders

The definition of apraxia specifies that the disturbance of performed skilled movements cannot be explained by the more elemental motor disorders typical of patients with movement disorders. Generally this does not present a significant diagnostic problem when dealing with 'higher-level' praxic disturbances (e.g. ideational apraxia), but it can be a major confound in establishing the presence of limb-kinetic apraxia. Most motor disturbances characteristic of extrapyramidal disorders, particularly bradykinesia and dystonia, will compromise the ability to establish the presence of loss of dexterity and deftness that constitutes this subtype. The term 'apraxia' has also been applied to other motor disturbances, such as 'gait apraxia' and 'apraxia of eyelid opening', that perhaps are misnomers, demonstrating the lack of a coherent nomenclature in this field. Apraxia is a hallmark of corticobasal degeneration (CBD) and historically this has received the most attention among the movement disorders. Corticobasal degeneration is characterized by various forms of apraxia affecting limb function, particularly ideomotor apraxia and limb-kinetic apraxia, although buccofacial and oculomotor apraxia can be present as well. The syndrome of parkinsonism and prominent apraxia, designated the 'corticobasal syndrome' (CBS), may be caused by a variety of other central nervous system pathologies including progressive supranuclear palsy (PSP), Alzheimer's disease, dementia with Lewy bodies and frontotemporal dementias. Distinct from the CBS, PSP and Parkinson's disease can demonstrate varying degrees of apraxia on selected tests, especially in those patients with more severe cognitive dysfunction. Diseases that cause the combination of apraxia and a primary movement disorder most often involve a variety of cerebral cortical sites as well as basal ganglia structures. Clinical-pathological correlates and functional imaging studies are compromised by both this diffuse involvement and the confusion experienced in the clinical evaluation of apraxia in the face of the additional elemental movement disorders. Finally, although apraxia results in clear disability in patients with the CBS, it is not clear how milder ideomotor apraxia found on specific testing contributes to patients' overall day-to-day motor disability.

Orofacial apraxia in corticobasal degeneration, progressive supranuclear palsy, multiple system atrophy and Parkinson's disease

OBJECTIVES

To determine whether the assessment of orofacial praxis is useful for the differential diagnosis of parkinsonian syndromes and to understand the neural mechanisms underlying OFA, searching for the respective roles of cortical and subcortical structures.

METHODS

Forty-four patients were assessed: 12 with idiopathic Parkinson's disease (IPD), 8 with multiple system atrophy (MSA), 12 with progressive supranuclear palsy (PSP) and 12 with corticobasal degeneration (CBD). An easy bedside scale was used, exploring single gestures, gestures with noise production and multiple sequential gestures. We searched for group and task effects.

RESULTS

Patients with CBD were significantly more impaired than those with IPD, MSA or PSP (p<0.001). Our assessment was unable to distinguish between the IPD, MSA and PSP groups. There was a clear task effect in CBD with a major impairment in multiple sequential gestures (p<0.0001).

CONCLUSION

Assessment of orofacial praxis helps in the clinical diagnosis of CBD. Patients with IPD, MSA and PSP did not present with OFA. We suggest that the deficit in multiple sequential gestures in CBD is related to simultaneous lesions of the parietal lobule and the supplementary motor area.

Clinical, cognitive and anatomical evolution from nonfluent progressive aphasia to corticobasal syndrome: a case report

Recent clinical and pathological studies have suggested that frontotemporal lobar degeneration (FTLD) and corticobasal syndrome (CBS) show clinical and pathological overlap. We present four years of longitudinal clinical, cognitive and anatomical data in the case of a 56-year-old woman, AS, whose clinical picture evolved from FTLD to CBS. For the first three years, AS showed a progressive speech and language disorder compatible with a diagnosis of the nonfluent aphasia variant of FTLD. At year four, 10 years after her first symptom, AS developed the classical clinical signs of CBS, including alien limb phenomenon and dystonia. Voxel-based morphometry (VBM) applied to AS's four annual scans showed progression of atrophy from the inferior posterior frontal gyrus, to the left insula and finally to the medial frontal lobe. This case demonstrates the clinical overlap between FTLD and CBS and shows that the two can appear in the same patient at different stages of the disease in relation to the progression of anatomical damage.

Corticobasal degeneration

Corticobasal degeneration is a progressive neurodegenerative disease that typically presents with asymmetrical parkinsonism and cognitive dysfunction. Recent molecular advances have given some clues to the pathogenesis of the disease. Clinical diagnosis is complicated by both the variability of presentation of true corticobasal degeneration, for example as a dementing illness, and the syndromes that look like it but are caused by other neurodegenerative diseases. Although definitive diagnosis of corticobasal degeneration can only be made at post-mortem examination, recent advances in imaging can assist the clinician with diagnosis. Treatment options remain limited and mostly address symptoms.