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Biomedical subjects

H Ackermann

Publications and source records attributed to H Ackermann.

At least 91 records · Page 5Linked to original sources
PubMed1993

Hemodynamics in subclavian-steal syndrome: difficulties in their evaluation.

In a patient with subclavian-steal syndrome transcranial Doppler sonography detected transient retrograde basilar blood flow whereas routine angiography failed to document this condition. Thus, orthograde basilar blood flow at routine angiography does not rule out basilar steal. Presumably the forced injection of contrast media conceals less pronounced steal phenomena. Our exemplary case indicates that a subgroup of patients with vertebro-basilar symptoms concomitant with basilar flow abnormalities may benefit from invasive or semi-invasive treatment.

Angiography↗
PubMed1993

[Prosodic disorders in neurologic diseases--a review of the literature].

The prosodic quality of speech comprises intonation, accent pattern, and rhythm. Among others, these dimensions contribute to the linguistic structure of an utterance and subserve emotional behaviour. Both cortical and subcortical dysfunctions can give rise to impaired speech prosody. The present paper reviews the clinical and linguistic features of the various dys- and aprosodic syndromes as well as their neuroanatomic substrates. 1. Sporadically, lesions of the left hemisphere present with dysprosody in terms of a "foreign accent". In most instances this syndrome seems to be due to apraxia of speech. 2. Some authors consider dysprosodic speech a characteristic feature of Broca's aphasia. The dysprosody of these patients predominantly reflects disturbed temporal organisation of speech utterances. Altered intonation contours, presumably, result from disordered sentence planning rather than from deficits of pitch processing. Wernicke aphasics may show increased variability of intonational patterns. 3. Impaired discrimination and identification of affective prosody has been observed in patients with temporoparietal lesion of the right hemisphere ("auditory affective agnosia"). With respect to linguistic prosody, controversial findings are reported on. Besides pitch extraction from acoustic signals the right hemisphere seems to provide categorical representations of emotional behaviour required for the "interpretation" of perceived intonation. 4. Damage to the right hemisphere can give rise to monotonous speech devoid of affective modulation ("motor aprosodia"). It is unsettled to which extent linguistic suprasegmental features are also distorted. The available data indicate an underlying dysfunction of basal ganglia loops and/or transcallosal projections. 5. Both Parkinson's and Huntington's disease may present with reduced prosodic modulation of speech. Probably, these deficits reflect disordered motor control of articulatory and phonatory functions. At least with respect to Parkinsonian patients perceptual and acoustic studies have so far failed to provide sufficient evidence of impaired prosodic planning.

Adult↗
PubMed1993

Speech freezing in Parkinson's disease: a kinematic analysis of orofacial movements by means of electromagnetic articulography.

Kinematic recordings of orofacial movements by means of electromagnetic articulography were performed in an akinetic-rigid Parkinsonian patient presenting with intermittent speech freezing in diadochokinesis tasks (rapid repetitions of the syllable /ta/). During freezing periods the patient produced a sustained /a/ instead of the required consonant-vowel sequences. The underlying articulatory trajectories were characterized by repetition rates amounting to 8-10 Hz concomitant with reduced movement amplitudes. Obviously, the undershooting of articulatory gestures failed to establish a sufficient occlusion of the vocal tract giving rise to the perceived speech freezing. In contrast, preserved diadochokinesis occurred at frequencies of 4-6 Hz. Most probably, the increased articulatory repetition rate reflects a pacing of orofacial movements by released tremor oscillations. Due to slowing of articulatory movements spastic dysarthrics can also present with missing syllabic modulation during oral diadochokinesis. The results of the articulographic recordings demonstrate the different pathophysiology of Parkinsonian freezing.

Articulation Disorders↗
PubMed1992

Neurophysiological evaluation of sensorimotor functions of the leg: comparison of evoked cortical potentials following electrical and mechanical stimulation, long-latency muscle responses, and transcranial magnetic stimulation.

Twenty-two patients with localized lesions of the central nervous system (unilateral cerebral ischaemia, cervical myelopathy, spinal tumour, familial spastic paraplegia) underwent neurophysiological evaluation of sensorimotor deficits of the leg. Functional methods using muscle stretch as stimulus, i.e. long-latency muscle responses and cortical potentials evoked by dorsiflection of the foot, were compared with transcranial magnetic stimulation and somatosensory evoked cortical potentials following electrical stimulation of the posterior tibial nerve. The functional neurophysiological methods yielded no diagnostic superiority with respect to the procedures using artificial (i.e. magnetic and electrical) stimulation. However, in most cases of missing compound motor action potentials following transcranial magnetic stimulation or missing electrically evoked cortical potentials, the long-latency muscle responses still allowed quantitative assessment of sensorimotor function.

Adult↗
PubMed1992

Speech deficits in ischaemic cerebellar lesions.

Twelve patients with cerebellar infarction, 8 in the region supplied by the posterior inferior cerebellar artery (PICA) and 4 in the territory of the superior cerebellar artery, underwent formal perceptual examination for speech deficits. With respect to topography the results firstly underline the significance of the paravermal region of the superior cerebellar portion for speech functions. In all patients with dysarthric impairment the lesion extended to this area, whereas patients with PICA infarction sparing the superior portion of the cerebellum showed no speech deficits. Secondly the findings do not corroborate the notion of an exclusively left-sided cerebellar speech motor control, since 3 of the 4 dysarthric subjects had unilateral right-sided ischaemia. This study thirdly demonstrates that lesions of the cerebellar cortex without involvement of the dentate nucleus can cause dysarthric impairment. Phonetic analysis revealed irregularly distributed articulatory deficits and slowed speech tempo as the most common dysarthric features.

Adult↗
PubMed1992

[Cerebellar dysarthria--a review of the literature].

This review summarizes and discusses the literature on speech deficits in cerebellar diseases and on the topography of cerebellar dysarthria. Clinical descriptions of dysarthric features in cerebellar diseases, parametric investigations of ataxic dysarthria, and experimental studies in animals concerning the effects of lesions on vocalization and the representation of sensorimotor orofacial functions in the cerebellum are considered. Signs of cerebellar dysarthria include a slowing down of articulatory movements, increased variability of pitch and loudness, monotonous and "scanning" speech, and articulatory impreciseness. The available data indicate that the paramedian regions of the superior cerebellar hemispheres are relevant for the development of cerebellar dysarthria.

Articulation Disorders↗
PubMed1991

Influence of an acoustic preparatory signal on postural reflexes of the distal leg muscles in humans.

In standing subjects the sudden displacement of a platform toe-up evokes a stabilizing postural response of the anterior tibial muscle (long-latency reflex). A preparatory signal (acoustic warning stimulus) preceding the postural perturbation by 1 s results in a significant decrease in latency of this long-latency response. There is no parallel modulation of the afferent cortical input in terms of evoked cerebral potentials following platform tilts toe-up nor of efferent cortico-spinal functions as evaluated by means of transcranial magnetic stimulation. Conceivable underlying mechanisms include faster intraspinal and/or intracortical processing of afferent input or switching to a shorter spinal reflex pathway.

Acoustic Stimulation↗
PubMed1991

Influence of posture and voluntary background contraction upon compound muscle action potentials from anterior tibial and soleus muscle following transcranial magnetic stimulation.

Compound muscle action potentials (CMAPs) were recorded from anterior tibial (TA) and soleus (SOL) muscles following transcranial magnetic stimulation of motor cortex in 10 healthy subjects: (1) while standing upright without support, (2) while sitting, and (3) while lying supine. The results of this study demonstrate a significant influence of posture upon the amplitudes of CMAPs. Postural facilitation presented itself, firstly, in terms of a higher incidence of bilateral activation of distal leg muscles during stance and, secondly, as significant enhancement of the amplitude of CMAPs while standing as compared to lying supine. The onset latency, however, did not disclose a significant shortening during stance. To assess the effects of preinnervation subjects voluntarily adjusted the level of TA activity to 5%, 10% and 20% of maximum isometric force respectively before cortex stimulation. Voluntary background contraction resulted in a significant increase of amplitude of CMAPs but, in contrast to postural facilitation, concomitant with a significant decrease in onset latency. These results point to a somewhat different mechanism of facilitation during stance as compared to voluntary preinnervation. But it cannot be decided whether cortical mechanisms, different descending systems, the spinal circuitry or a combination of these factors is responsible for the observed effects.

Adult↗
PubMed1991

Cerebellar voice tremor: an acoustic analysis.

Patients with cerebellar disease may exhibit tremulous phonation as part of their dysarthria. The results of an acoustic analysis of cerebellar voice tremor in a patient with hereditary ataxia and presenting with a purely cerebellar syndrome are reported. Analysis included computation of speech intensity contours, fundamental frequency contours, and spectral parameters from sustained productions of vowels and voiceless fricatives. Fundamental frequency contours during sustained phonation of vowels showed rhythmic oscillations at a rate of about 3 Hz. No concomitant periodicity could be detected for the parameters characterising voiceless fricative production. The results indicate an impairment of phonatory control in relation to the maintenance of a constant isometric activity of the internal laryngeal muscles. Cerebellar voice tremor may therefore be classified as a form of postural tremor.

Cerebellum↗
PubMed1991

Articulatory deficits in parkinsonian dysarthria: an acoustic analysis.

Twelve patients with idiopathic Parkinson's disease had acoustic speech analysis of sentence utterances to provide information on speech tempo and accuracy of articulation. As a measure of rate of speech the duration of opening-closing movements during articulation was determined from speech wave variables. The intensity of sound emission during articulatory closure as required for stop consonant production, for example, magnitude of p, magnitude of t, magnitude of k, was used as an index of the degree of closure. Speech tempo was not significantly different from normal. The patients, however, had a reduced capacity of completing articulatory occlusion. This was interpreted as reflecting a reduction in movement amplitude of the articulators. Articulatory "undershoot" was not uniform but influenced by linguistic demands in that the closures associated with a stressed syllable were performed at the expense of unstressed ones. Furthermore, switching between opening and closing movements of the articulators in sentence production seemed undisturbed. These results indicate that motor planning of speech differs from arm movement control.

Adult↗
PubMed1989

[Dysarthrophonia of Parkinson syndrome].

Disorders of speech are a common and sometimes even the first symptom of parkinsonism. The various features of parkinsonian speech disorder include repetitive phenomena, disturbances of respiration, dysphonia, and impairment of articulation. This review aims at summarizing the neurological, phoniatric, and phonetical data regarding symptomatology, pathophysiology, and therapy of parkinsonian dysarthrophonia.

Dysarthria↗
PubMed1989

[Comparison of angiography and continuous-wave Doppler sonography in the diagnosis of subclavian stenoses and of the subclavian steal syndrome].

Angiographic control of ultrasonographic findings (continuous-wave (CW) Doppler sonography) at the subclavian artery was performed in 149 patients, altogether 254 subclavian arteries, 89 with and 165 without stenosis or occlusion at Doppler examination. Additionally, in 70 of these persons the vertebral haemodynamic situation was investigated by means of angiography. CW Doppler sonography proved a highly reliable method for the diagnosis of subclavian lesions and subclavian steal syndrome. If properly performed, CW Doppler sonography does not fail to reveal stenoses amounting to more than 50%, occlusions, and retrograde vertebral blood flow. Regarding tight stenosis or occlusion of the subclavian artery and retrograde blood flow in the vertebral artery, Doppler sonography yielded no false positive findings, but false positive results may be possible in mild stenoses.

Adolescent↗
PubMed1989

[The effectiveness of the new morantel sustained-release trilaminate bolus against gastrointestinal nematode infections in cattle in their first grazing period].

The efficacy of a recently developed Morantel-Sustained-Release-Trilaminate-Bolus (Paratect Flex Bolus [PFB]-Pfizer Inc.) against gastrointestinal nematode infections in cattle was assessed by monitoring faecal egg counts (EpG), herbage larval counts, serum pepsinogen levels and liveweight gains in first season calves. In two field trials (1987 and 1988), a PFB-Bolus was administered to two different groups of animals (1987: 15 calves; 1988:13 calves) at turnout (29 May 1987; 26 May 1988), control groups were included. In 1988, 13 calves received for comparison an Oxfendazole-Release-Bolus (Systamex Intervall Bolus [OXF]-Coopers Inc.). All groups were grazed on adjacent but separately fenced pastures throughout the season, until housing (27 October 1987; 15 October 1988). When compared with controls, the PFB-groups showed significantly lower EpG values and consequently, lower herbage larval counts throughout the season in both trials. From day 30 after turnout, the PFB-group had significantly lower serum pepsinogen levels, which reflects the low degree of abomasal damage in these animals. When compared to controls, the PFB-treated animals showed significantly higher weight performances. The mean weight-gain benefit of PFB-treated animals was +12.5 kg (p less than 0.05) and +21.1 kg (p less than 0.005) in 1987 and 1988, resp. No difference occurred between PFB-treated and OXF-treated calves, the latter outperformed the control animals by +21.6 kg (p less than 0.005).

Animals↗
PubMed1988

[The effect of microbial protein, obtained on a hydrocarbon base (fermosin), with a defined fatty acid composition on fat metabolism and fat composition in slaughter animals. 1. The effect of fermosin on the composition of broiler depot fat].

A study has been undertaken to investigate the influence of fermosin on the depot-fat composition of broilers and the oxidative stability of these fats in parallel with test animals fed yeast conventional produced on carbohydrate base. The data obtained are discussed with reference to literature.

Adipose Tissue↗
PubMed1988

Ultrasonographic follow-up of subclavian stenosis and occlusion: natural history and surgical treatment.

Continuous-wave Doppler ultrasonography and clinical examination were used over a 2-year period to monitor the natural history of subclavian stenoses and occlusions in 67 patients. Thirty-nine presented with subclavian steal and 28 without. We also studied an additional group of 29 patients who had undergone surgery for subclavian steal syndrome and vertebrobasilar transient ischemic attacks. The results, in terms of both ultrasonographic and clinical criteria, demonstrate the benign nature of the subclavian steal syndrome: all neurologic signs and symptoms were of a transient character. Spontaneous remission of vertebrobasilar transient ischemic attacks occurred in approximately 50% of the initially symptomatic patients, and only 15% of the initially asymptomatic patients experienced vertebrobasilar transient ischemic attacks during follow-up. Doppler ultrasonography revealed progression during follow-up in only 17% of the subclavian stenoses, and in 13% a stenosis was no longer detectable. Still-ongoing brainstem transient ischemic attacks were reported in 24% of the operated patients. The most important factor for the lack of improvement was the occlusion of the bypass. Continuation of transient neurologic symptoms could be observed in only 14% of the patients with intact carotid-subclavian bypass. In conclusion, indications for surgical treatment of the subclavian steal syndrome should be restricted to cases in whom vertebrobasilar transient ischemic attacks occur frequently and are either debilitating or greatly frighten the patient.

Arterial Occlusive Diseases↗
PubMed1987

Stenosis and occlusion of the subclavian artery: ultrasonographic and clinical findings.

Continuous-wave (CW) Doppler sonography has proved to be a reliable tool both to detect subclavian stenosis or occlusion and to detect reversal of blood flow in the vertebral artery. This method is entirely atraumatic and in contrast to angiography allows investigation of asymptomatic patients and provides more representative data for epidemiological studies. The incidence of subclavian stenosis or occlusion was 1.15% among the 23,500 patients examined in our department between 1978 and 1985. Of the 272 patients with unilateral or bilateral subclavian stenosis or occlusion, 54% were asymptomatic with no subjective complaints and were normal upon neurological examination; 29% reported vertebrobasilar transient ischaemic attacks (TIAs), with or without concomitant TIAs or infarction in the vascular territory of the carotid arteries; and 17% complained of symptoms exclusively referring to the region of carotid blood supply. Reversal of blood flow in the ipsilateral vertebral artery was detected in 152 patients (56%). The incidence of neurological symptoms within this group was double that found in patients without steal. None of the patients suffered from permanent vertebrobasilar damage. In most cases, subclavian artery disease was due to atherosclerosis. For 13 patients an inflammatory, iatrogenic, traumatic, or congenital aetiology could be assumed. The marked preponderance of left-sided subclavian stenosis or occlusion, reported by others, could be confirmed among our patients, but was less pronounced for tight stenoses than for occlusions. Mild-to-moderate subclavian stenoses were about equally distributed on each side.

Adolescent↗