Blink amplitude but not saccadic hypometria indicates carriers of Parkin mutations

Helmchen, Christoph; Schwekendiek, A.; Pramstaller, Peter P.; Hedrich, Katja; Klein, Christine; Rambold, H.

doi:10.1007/s00415-006-0168-1

Cited by 10 publications

(7 citation statements)

References 21 publications

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“…Further strengthening the notion of a potential role of heterozygous Parkin mutations as a susceptibility factor, asymptomatic carriers of a single Parkin mutation from the same family demonstrated subclinical changes on investigation with detailed neurophysiological and neuroimaging techniques. Specifically, mutation carriers had a higher blink amplitude than controls and also showed reorganization of striatocortical motor loops upon functional MRI [8,13]. Confirming the notion of preclinical changes reflected by SN hyperechogenicity, we and others showed a significant negative correlation between FDOPA uptake in the posterior putamen and ipsilateral extension of echogenic signals in the SN in asymptomatic heterozygous mutation carriers D [14,15].…”

Section: Discussionsupporting

confidence: 87%

Substantia nigra hyperechogenicity correlates with clinical status and number of Parkin mutated alleles

et al. 2007

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To further evaluate (1) transcranial sonography (TCS) for (pre)clinical diagnosis of Parkinson's disease (PD) and (2) to examine asymptomatic carriers of Parkin mutations we investigated substantia nigra (SN) hyperechogenicity in PD patients and unaffected subjects with and without Parkin mutations. The area (aSN) of the hyperechogenic SN were calculated bilaterally and study subjects were assigned to high versus low value groups. Eleven of the (affected and unaffected) mutation carriers had previously undergone 18-fluoro-dopa-(FDOPA)-PET scans. Fifty-eight individuals were investigated, including 24 with clinically definite and 34 without symptoms or signs of PD. Of the patients, three had one mutated and six had two mutated Parkin alleles. Of the unaffected subjects, 13 carried a single Parkin mutated allele. After dichotomization, 21 subjects had high and 37 subjects low values of mean aSN. Regarding the clinical status, 13 (62%) of the individuals with a high mean aSN had PD,while 26 (70%) of the study subjects with low values did not show signs of PD (p = 0.0393). Similarly, probands with high mean aSN values more frequently carried Parkin mutations (58%) than probands with low values (27%, p = 0.0234). A negative correlation between FDOPA uptake in the posterior putamen and maximum aSN was found in the group of mutation carriers (r = -0.809, p = 0.0234). In conclusion, hyperechogenicity of the SN is found in both idiopathic and Parkin-associated PD. Further strengthening the notion of a potential relationship between SN hyperechogenicity and Parkin mutational status, a larger aSN was associated with an increasing number of mutated alleles in our study.

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Section: Discussionsupporting

confidence: 87%

Substantia nigra hyperechogenicity correlates with clinical status and number of Parkin mutated alleles

et al. 2007

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“…It has to be kept in mind that both the development and progression of PD in PINK1 mutation carriers are usually slow, and only a minority of heterozygous PINK1 mutation carriers will develop parkinsonian signs during their lifespan 16. However, we and others have recently shown in clinical,6 behavioural and imaging studies that heterozygous mutations may play a role in the pathophysiology of PD, as documented, for example, in asymptomatic heterozygous carriers of Parkin mutations,17 18 the most frequent cause of recessive early-onset PD. Accordingly, follow-up examinations of the asymptomatic PINK1 mutation carriers including skin biopsies are necessary to determine whether sensory abnormalities, which can be detected prior to the development of pronounced clinical motor symptoms of PD, might possibly help to identify PINK1 mutation carriers at risk of developing PD.…”

Section: Discussionmentioning

confidence: 99%

Somatosensory processing in a German family with PINK1 mutations: its potential role in Parkinson disease

Gierthmühlen

Lienau²,

Maag³

et al. 2009

Journal of Neurology, Neurosurgery & Psychiatry

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Background: It is unclear whether sensory symptoms in Parkinson disease (PD) are of primary or of secondary origin attributable to motor symptoms such as rigidity and bradykinesia.Objective: The aim of this study was to elucidate whether sensory abnormalities are present and may precede motor symptoms in familial parkinsonism by characterizing sensory function in symptomatic and asymptomatic PINK1 mutation carriers. Methods: Fourteen family members with PINK1 mutation and 14 healthy controls were examined clinically, with nerve conduction studies and quantitative sensory testing (QST). Results: Thresholds for mechanical detection, mechanical pain and pressure pain were higher in PINK1 mutation carriers compared to controls. Higher thresholds for mechanical detection, mechanical pain and pressure pain were even found in asymptomatic, clinically not or only mildly affected PINK1 mutation carriers. Conclusions: Data suggest that PINK1-associated PD is associated with a primary hypofunction of nociceptive and non-nociceptive afferent systems that can already be found at the time when motor signs of PD are only subtle. As nerve conduction studies did not reveal differences between PINK1 mutation carriers and controls, we propose that the somatosensory impairment is related to abnormal central somatosensory processing.

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“…This indicates that such deficits could be a pre-clinical stage of Parkinson’s Disease [39,40]. Though, other studies show that such a relationship does not exist, and argue that occurrence is due to exposure to the same unknown environment [40,41]. However, there are two genetic factors related to cognitive dysfunction in PD: the genes for catechol-O-methyltransferase and microtubule associated tau protein [42].…”

Section: Introductionmentioning

confidence: 99%

Time perception impairs sensory-motor integration in Parkinson’s disease

Lucas¹,

Chaves²,

Teixeira³

et al. 2013

Int Arch Med

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It is well known that perception and estimation of time are fundamental for the relationship between humans and their environment. However, this temporal information processing is inefficient in patients with Parkinson’ disease (PD), resulting in temporal judgment deficits. In general, the pathophysiology of PD has been described as a dysfunction in the basal ganglia, which is a multisensory integration station. Thus, a deficit in the sensorimotor integration process could explain many of the Parkinson symptoms, such as changes in time perception. This physiological distortion may be better understood if we analyze the neurobiological model of interval timing, expressed within the conceptual framework of a traditional information-processing model called “Scalar Expectancy Theory”. Therefore, in this review we discuss the pathophysiology and sensorimotor integration process in PD, the theories and neural basic mechanisms involved in temporal processing, and the main clinical findings about the impact of time perception in PD.

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Blink amplitude but not saccadic hypometria indicates carriers of Parkin mutations

Cited by 10 publications

References 21 publications

Substantia nigra hyperechogenicity correlates with clinical status and number of Parkin mutated alleles

Substantia nigra hyperechogenicity correlates with clinical status and number of Parkin mutated alleles

Somatosensory processing in a German family with PINK1 mutations: its potential role in Parkinson disease

Time perception impairs sensory-motor integration in Parkinson’s disease

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