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PubMed1996

Ideomotor apraxia and cerebral dominance for motor control.

Ideomotor apraxia is a symptom of left hemisphere damage. Patients with ideomotor apraxia commit errors when imitating movements with their left, non-paralyzed hand. This has been taken as evidence for a motor dominance of the left hemisphere. It has been hypothesized that the left hemisphere is dominant for internal preprogramming of skilled movements of either hand. We investigated the kinematics of movement trajectories of imitation of meaningless gestures. Group analysis confirmed that hesitant, feedback-controlled movement prevail in patients with apraxia, but analysis of single cases revealed the existence of kinematically normal movements leading to apractic errors. Enhanced reliance on feedback-control appears to be a compensatory strategy rather than the source of apractic errors. In a second study we explored the alternative hypothesis that patients with apraxia lack a general concept of the human body which is necessary to mediate the translation of a target position seen on the model into a target position on the patient's body. Imitation of movements was examined on oneself and on a mannikin. Patients with apraxia who made errors when imitating on themselves committed errors also when imitating on the mannikin. Taken together, both studies support the view that the source of errors in the imitation of gestures is to be sought at a conceptual level. This casts doubts on the alleged dominance of the left hemisphere for motor control.

Apraxias↗
PubMed2005

Tapping, grasping and aiming in ideomotor apraxia.

Very few studies have investigated sensorimotor control in apraxia using tasks that differ in movement complexity. Nevertheless, there is some evidence to suggest that spontaneous behaviour, although relatively preserved, can be rather clumsy or awkward, and that patients with ideomotor apraxia may have subtle kinematic abnormalities in movements made in the laboratory. It remains unclear whether patients with ideomotor apraxia perform normally on movements such as visually guided aiming, that may not depend on higher-order, more cognitive, processes and that are relatively unguided by overlearned contexts. In this study, three different sensorimotor tasks were given to the same sample of patients with quantified apraxic disturbance. Finger tapping, goal-directed grasping and aiming with and without visual feedback were examined in these patients. A clear dissociation was found between grossly impaired gesture imitation and intact motor programming of goal-directed movements with visual feedback. Apraxic patients were, however, impaired on aiming movements without visual feedback, suggesting that apraxia is associated with an increased reliance on integration of online visual information with feedforward/feedback somatosensory and motor signals. Furthermore, patients were impaired on single finger tapping which was a surprisingly good predictor of apraxia severity.

Aged↗
PubMed2006

A new account of face apraxia based on a longitudinal study.

The aim of this paper is to provide an interpretation of face apraxia which accounts also for the role of right hemisphere lesions. Thirty-one patients with left hemisphere (L/pts) and 31 patients with right hemisphere (R/pts) lesions entered a cross-sectional study to identify those presenting with either lower or upper face apraxia. The 16L/pts and 8R/pts who presented with face apraxia in the acute stage and could be retested 4 months later, were followed up longitudinally. The degree of recovery did not differ between the two groups of patients. The traditional hypothesis of face apraxia based on the presence of a left-sided praxis centre could not account for these findings. A new trade-off model of face praxis resources distributed across the two hemispheres is presented. This model, based on individual differences in the healthy brain, accounts for the presence and persistence of face apraxia in a proportion of R/pts.

Aged↗
PubMed1995

Ecological implications of limb apraxia: evidence from mealtime behavior.

Humans learn skilled acts in order to effectively interact with their environment. A loss of the ability to perform skilled acts is termed apraxia. Apraxia has been thought to be of theoretical interest, but the ecological implications of apraxia are controversial and have not been fully studied. We examined ten patients with unilateral left hemisphere cerebral infarctions (eight of whom were apraxic) and compared their mealtime eating behavior to a group of neurologically normal, age-matched controls. The stroke patients were less efficient in completing the meal. They made more action errors and were less organized in the sequencing of mealtime activities. Because the patients made more errors while using tools than when performing nontool actions, their deficit could not be accounted for by an elemental motor deficit. A positive relationship was found between mealtime action errors and the severity of apraxia. These findings suggest that limb apraxia may adversely influence activities of daily living.

Activities of Daily Living↗
PubMed1996

Speech timing in apraxia of speech versus conduction aphasia.

This study examined temporal parameters of speech in subjects with apraxia of speech, conduction aphasia, and normal speech. They were asked to repeat target words in a carrier phrase 10 times. Acoustic analyses involved measurement of stop gap duration, voice onset time, vowel nucleus duration, and consonant-vowel (CV) duration. Speakers with apraxia of speech had longer and more variable stop gap, vowel, and CV durations than did subjects with aphasia or normal speech. Speakers with conduction aphasia had longer vowel durations and CV durations than subjects with normal speech. Also, subjects with apraxia of speech showed greater token-to-token variability than the other subject groups. The variability shown by subjects with apraxia of speech was significantly correlated with perceptual judgments of their speech. The significance of these results is discussed in the context of motoric and phonological explanations for apraxia of speech and conduction aphasia.

Adult↗
PubMed1998

Lip EMG activity during vowel production in apraxia of speech: phrase context and word length effects.

This investigation examined the timing relationships of EMG activity underlying vowel production in 2 normal individuals and in 2 individuals with marked-to-severe apraxia of speech of approximately two-and-one-half years duration. The timing of lip muscle activity was investigated in monosyllabic words embedded in phrases and in syllable word stems as a function of changes in word length. Specifically, the onset and offset of EMG activity of lip muscles used for production of /u/ in the monosyllables and word stems were examined. The results revealed that the relative amounts of time devoted to onset and offset of EMG activity for lip rounding are disorganized in apraxia of speech. Word length appeared to affect the timing of the onset of muscle activity for both the normal speakers and the speakers with apraxia of speech. Word length also influenced the offset of muscle activity, but its effect was less systematic for the speakers with apraxia of speech. The findings suggest that termination of EMG activity may be at least as disturbed as the initiation of EMG activity in apraxia of speech.

Apraxias↗
PubMed1989

[Speech apraxia--an apraxic disorder?].

This article presents arguments supporting the view that apraxia of speech is an apraxic disorder. In a first part the most salient clinical signs of the syndrome are reviewed. Among these, the symptom of inconsistent distortions and categorical aberrations of speech sounds is emphasized for its relevance in differentiating apraxia of speech from the dysarththrias on the one hand and from aphasic phonological disturbances on the other. In a second part, the diagnostic criteria of apraxia of speech are compared to those of oral (nonverbal) apraxia. In this comparison, a full correspondence between the two syndromes can be stated. Finally we discuss the principal arguments that have been raised against the concept of verbal apraxia.

Aphasia↗
PubMed2003

Ideomotor and ideational apraxia in corticobasal degeneration: a case study.

Corticobasal degeneration (CBD) is a progressive disorder that can be characterised by asymmetrical akinetic rigidity, involuntary movements, cortical sensory loss, alien limb syndrome and asymmetrical apraxia (Gibb et al., 1989; Rinnie et al., 1994). Diagnosis of praxic disabilities is thought to be essential for distinguishing CBD, in its early stage, from other akinetic-rigid syndromes. However, the nature of apraxia in CBD, and the relations between ideomotor and ideational apraxia, are not well understood. For example, if there is an ideational deficit in a given patient, does this deficit occur independently of any ideomotor disorder, or are the two impairments linked in some manner? In the present paper we report a case study of a patient with apraxia due to CBD. We examine whether the disorder is confined to production tasks, or whether there is also a related deficit in recognising the correct actions performed with objects (an ideational deficit). We also evaluate whether a disorder found for action with single objects dissociates from the ability to link multiple actions into more complex, everyday tasks. The performance of our patient showed an impairment in both action production and action recognition system, suggesting a component of ideational as well as ideomotor apraxia in CBD.

Apraxia, Ideomotor↗
PubMed2006

The significance of clumsy gestures in apraxia following a left hemisphere stroke.

Individuals who sustain a cerebrovascular accident (CVA) in the dominant (typically left) hemisphere, are at increased risk of developing motor skill deficits due to motor-sensory impairments, as well as cognitive impairments (e.g., apraxia). Clumsiness is a central component affecting motor skills in individuals with a left hemisphere CVA (LCVA). The term "clumsiness" however, has not been adequately operationalised in the apraxia literature in clinical terms, thereby making diagnosis difficult and its contribution to apraxic disorders uncertain. Accordingly, in this study "clumsiness" was explicitly defined by establishing a set of four criteria. The non-dominant (left) hand movements of three groups of participants were examined: 10 individuals with limb-apraxia (APX); 8 individuals without limb apraxia who had sustained a LCVA (NAPX); and 19 healthy individuals without a history of brain impairment (NBD). Performance was examined on four sets of motor tasks, including a conventional praxis test, basic perceptual-motor co-ordination and fine movement tasks, and a naturalistic actions test. A striking finding that emerged was that clumsy errors occurred frequently in all groups, including the NBD group, particularly on the praxis and fine motor tasks. In terms of quantity of clumsy errors emitted, the APX group made significantly more clumsy gestures across all four tasks in comparison to the NBD group. No differences emerged between the two clinical groups, however, in terms of total clumsy gestures emitted on the naturalistic action tasks, or the type of clumsy errors emitted on the fine motor tasks. Thus, frequency and types of clumsy gestures were partly determined by task demands. These results highlight the need to consider the contribution of clumsy gestures in limb functioning following hemispheric brain damage. In broad terms, these findings emphasise the importance of adopting more detailed analyses of movement errors in apraxia and assessments of cognitive-based motor functioning following brain impairment.

Aged↗
PubMed2005

Limb apraxia and cognitive impairment in progressive supranuclear palsy.

Limb apraxia occurs in progressive supranuclear palsy (PSP); however, its characteristics and relation to dementia are unclear. We compared 25 probable PSP patients on cognitive and ideomotor apraxia tests with 19 healthy controls. Eleven PSP patients were demented (D-PSP) and 14 not (ND-PSP). D-PSP patients did worse than controls and ND-PSP patients in all cognitive tests; and ND-PSP patients did worse than controls in all except the memory test. In the apraxia test, PSP patients committed mainly sequence errors and executed complex gestures badly. Apraxia correlated strongly with dementia. In PSP, limb apraxia seems mainly due to frontal deafferentation and lesions, but only when these are severe enough to cause dementia.

Aged↗
PubMed2006

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.

Apraxias↗
PubMed1992

Neuropsychological and neuroanatomical dimensions of ideomotor apraxia.

Fifty-five right-handed men with left hemisphere stroke were systematically investigated for ideomotor apraxia of various body parts. Standardized aphasia and apraxia examinations in all cases, and appropriately timed CT in 28 cases, were used for analysis of psychological and anatomical properties of ideomotor apraxia. It is not possible to ignore the modality of eliciting the movement (command or imitation) and the body part being moved (buccofacial, limb or whole body) from any comprehensive theory about ideomotor apraxia. Different levels of performance are seen with different body parts to different modalities in different aphasic groups. Some subtypes of ideomotor apraxia (buccofacial) have highly specified anatomical basis. Some (limb) have apparently distributed anatomies, and others (whole body) have as yet unknown bases.

Adult↗
PubMed2001

Tactile apraxia: unimodal apractic disorder of tactile object exploration associated with parietal lobe lesions.

Tactile apraxia is characterized by an isolated disturbance of hand movements for use of and interaction with an object (transitive movements) in the presence of preserved intransitive movements (movements without use of an object, for example repetitive movements or gestures). It is, however, still unclear whether motor and sensory abnormalities represent causal or associated features of tactile apraxia. To address this question, quantitative kinematic recordings of exploratory finger movements (transitive movements) and rapid alternating finger movements (intransitive movements) were studied in 20 healthy volunteers and 22 patients with focal lesions of the parietal, anterofrontal and motor cortex. The most severe deficits of manual object exploration were found in patients with parietal lesions, using the hand contralateral to the lesion. Patients with lesions of the anterior parietal lobe who exhibited prominent sensory deficits and astereognosia showed a decrease in frequency and regularity of exploratory finger movements and a marked increase in exploration space. Patients with posterior parietal lesions exhibiting severe astereognosia, apraxia and deficits in dexterity had a greater decrease in frequency and regularity of manipulative movements, but a less pronounced increase of exploration space than the patients with anterior parietal lesions. Although the patients with parietal lobe lesions could generate rapid alternating finger movements, the regularity of these movements was also impaired. In comparison, patients with frontal lobe lesions exhibited impaired contralesional manipulatory and rapid alternating finger movements but no sensory abnormalities or astereognosia. We conclude that tactile apraxia represents a deficit in the programming of exploratory finger movements mediated by the parietal lobe. The comparison with lesions of other regions participating in the cortical network for tactile exploration reveals that apraxia of exploratory movements in parietal lobe lesions represents a disturbance distinct from elementary motor or sensory abnormalities, but closely related to stereognostic functioning.

Adolescent↗
PubMed1983

Apraxia in deep cerebral lesions.

In a series of 50 patients with cerebrovascular lesions (demonstrated with CT scan), seven patients had lesions located in the basal ganglia and/or thalamus. All these seven patients were apractic. Ideomotor apraxia was present in all patients; five also had constructional apraxia, and one had bucco-facial apraxia. None of the patients had utilisation apraxia. These observations indicated that apraxia is not only a "high cerebral (cortical) function", but may depend also on the integrity of subcortical circuits and structures.

Adult↗
PubMedDate not supplied

Aphasia, apraxia, and agnosia in the diagnosis of dementia.

The association of aphasia, apraxia and agnosia with cortical but not subcortical dementias, is a widely held belief. The purpose of the present study was to determine the frequency of aphasia, apraxia, and agnosia in groups of cortical and subcortical dementia patients, and to assess the diagnostic utility of these symptoms. Subjects were 64 patients with subcortical dementias (Parkinson's disease and normal pressure hydrocephalus) and 192 patients with cortical dementia (probable Alzheimer's disease) matched for sex, age, and Mini-Mental State Examination score. Each patient was evaluated for the presence of aphasia, apraxia, and agnosia. Results indicated that only aphasia was reported significantly more often in cortical dementia patients than in subcortical dementia patients. The presence of either of these three symptoms has very low diagnostic sensitivity, specificity, and total predictive value. The severity of the patient's dementia was predicted whether the patient had aphasia or apraxia; type of dementia had no predictive value. These data led to the conclusion that cortical and subcortical dementias cannot be reliably dissociated on the basis of aphasia, apraxia, or agnosia.

Aged↗
PubMed2000

Prevalence of apraxia among patients with a first left hemisphere stroke in rehabilitation centres and nursing homes.

OBJECTIVE: To investigate the prevalence of apraxia in patients with a first left hemisphere stroke. SUBJECTS: Left hemisphere stroke patients staying at an inpatient care unit of a rehabilitation centre or nursing home and receiving occupational therapy (n = 600). MEASURES: A short questionnaire on general patient characteristics and stroke-related aspects was completed by occupational therapists for every left hemisphere stroke patient they treated. A diagnosis of apraxia or nonapraxia was made in every patient, on the basis of a set of clinical criteria. RESULTS: The prevalence of apraxia among 492 first left hemisphere stroke patients in rehabilitation centres was 28% (96/338) and in nursing homes 37% (57/154). No relationship was found between the prevalence of apraxia and age, gender or type of stroke (haemorrhage or infarct). CONCLUSIONS: This study shows that approximately one-third of left hemisphere stroke patients has apraxia.

Adult↗
PubMed1998

Carbamazepine responsive epileptic oral motor and ocular motor apraxia.

We evaluated seven patients with oral motor apraxia and ocular motor apraxia. Apraxia in three patients (Group 1) with new-onset partial seizures and epileptiform discharges on EEG improved with carbamazepine. Four patients (Group 2) without seizures and nonepileptiform EEG findings had no change in apraxia after a trial of carbamazepine. Epileptic apraxia may precede clinical seizures and can respond to antiepileptic drugs.

Anticonvulsants↗
PubMed1994

Concurrent validity of the Kaufman Hand Movement Test as a measure of limb apraxia.

The concurrent validity of the Kaufman Hand Movement Test as a measure of limb apraxia was investigated. For 23 adult aphasic subjects, a Pearson r of 0.84 was obtained between scores on this test and on the Limb Apraxia Test, a battery of tasks often used in the assessment of limb apraxia. The Kaufman test is a shorter and simpler test to administer than the Limb Apraxia Test. The concurrent validity of the Kaufman test encourages its use in the assessment of limb apraxia.

Adult↗