Lymph Scintigraphy and Pre- and Intraoperative Gamma Prone Measurements for Localization of Sentinel Lymph Nodes (SLN) in Breast Cancer

Aim of this study was to prove the clinical value of nuclear medicine procedures to detect the sentinel lymph node (SLN) for SLN biopsy. Methods: In 132 patients with breast cancer we performed lymph scintigraphy of the breast as well as both pre- and intraoperative gamma probe measurements correlating the results with the findings of histopathology. Results: SLN were detectable in 62 of 110 patients according to a sensitivity of 56% when scanning was performed only at 1-2 h p.i. while the sensitivity increased to 86% (19 of 22 pts.) if sequential images were acquired up to 2 h p.i. One or more SLN were identified by a handheld gamma probe transcutaneously prior to surgery in 96% (113 of 118 pts.) of the patients who showed up with no clinically suspected lymph node metastases. Intraoperatively, in additionally 2 patients the SLN could be found resulting in a sensitivity of 97% (115 of 118 pts.). In only 3 patients with clinically no tumor spread to axillary lymph nodes no SLN could be identified by the probe. Skip lesions, i.e. lymph node metastases in patients with tumorfree SLN, occured in 2 cases: due to SLN biopsy in these patients lymph node staging was false negative compared to conventional staging by means of axillary lymph node dissection. Conclusion: The results demonstrate a high preoperative detection rate of SLN in patients with breast cancer using lymph scintigraphy and gamma probe measurements. Thus, nuclear medicine is capable of providing the basic requirements for SLN biopsy in the daily routine.

Genome-wide association studies of smooth pursuit and antisaccade eye movements in psychotic disorders: findings from the B-SNIP study

Eye movement deviations, particularly deficits of initial sensorimotor processing and sustained pursuit maintenance, and antisaccade inhibition errors, are established intermediate phenotypes for psychotic disorders. We here studied eye movement measures of 849 participants from the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP) study (schizophrenia N=230, schizoaffective disorder N=155, psychotic bipolar disorder N=206 and healthy controls N=258) as quantitative phenotypes in relation to genetic data, while controlling for genetically derived ancestry measures, age and sex. A mixed-modeling genome-wide association studies approach was used including ~4.4 million genotypes (PsychChip and 1000 Genomes imputation). Across participants, sensorimotor processing at pursuit initiation was significantly associated with a single nucleotide polymorphism in IPO8 (12p11.21, P=8 × 10-11), whereas suggestive associations with sustained pursuit maintenance were identified with SNPs in SH3GL2 (9p22.2, P=3 × 10-8). In participants of predominantly African ancestry, sensorimotor processing was also significantly associated with SNPs in PCDH12 (5q31.3, P=1.6 × 10-10), and suggestive associations were observed with NRSN1 (6p22.3, P=5.4 × 10-8) and LMO7 (13q22.2, P=7.3x10-8), whereas antisaccade error rate was significantly associated with a non-coding region at chromosome 7 (P=6.5 × 10-9). Exploratory pathway analyses revealed associations with nervous system development and function for 40 top genes with sensorimotor processing and pursuit maintenance (P=4.9 × 10-2-9.8 × 10-4). Our findings suggest novel patterns of genetic variation relevant for brain systems subserving eye movement control known to be impaired in psychotic disorders. They include genes involved in nuclear trafficking and gene silencing (IPO8), fast axonal guidance and synaptic specificity (PCDH12), transduction of nerve signals (NRSN1), retinal degeneration (LMO7), synaptic glutamate release (SH3GL2), and broader nervous system development and function.

[Video-based head impulse test. Importance for routine diagnostics of patients with vertigo]

Dizziness is one of the most common complaints in Germany which leads to medical consultation. Diagnosis is based on patient history, clinical examination and laboratory tests. In order to find or exclude a vestibular lesion, methods such as caloric irrigation, rotational chair tests or vestibular-evoked myogenic potentials were previously applied. Recently, a new diagnostic tool has been made available for application in daily practice: the video head impulse test (vHIT). Due to the easy and fast application for the examiner, good tolerance by the patient and high sensitivity for vestibular lesions, the vHIT has the potential to improve the diagnosis and therapy of patients suffering from vertigo in widespread medical care in Germany. This article reports on experiences with this new method after examination of over 1,500 patients in the academic vertigo centre in Lübeck. The principles and application of the vHIT in daily clinical routine are described and the many advantages but also some pitfalls are highlighted. As a consequence of a wider clinical use it is expected that the vHIT will lead to an increased detection of vestibular dysfunctions not only in clinically suspected vestibular diseases but also in other common neurological diseases (e.g. polyneuropathy or cerebellar ataxia). This may change the prevalence of different vestibular diseases, broaden knowledge about other common diseases with gait imbalance as the leading symptom and provide a quantitative measure that can be used to longitudinally assess the effects of therapeutic interventions.

Autosomal dominant Parkinson's disease in a large German pedigree

OBJECTIVE

While several genes have been identified to cause Parkinson's disease (PD), monogenic forms explain only a small proportion of cases. We report clinical and genetic results in a large family with late-onset autosomal dominant PD.

METHODS

Thirty-eight family members of a five-generation Northern German PD family underwent a detailed neurologic examination, and transcranial sonography was performed in fifteen of them. Comprehensive mutation analysis of known PD-causing genes and a genome-wide linkage analysis were performed.

RESULTS

Late-onset definite PD was found in five subjects with a mean age at onset of 63 years. Another six individuals presented either with probable/possible PD or with subtle parkinsonian signs. Six members with a mean age of 79 years had an essential tremor phenotype. Mode of PD inheritance was compatible with autosomal dominant transmission. One of three examined patients with definite PD demonstrated an increased area of substantia nigra hyperechogenicity upon transcranial sonography. Comprehensive linkage and mutational analysis excluded mutations in known PD-causing genes. Genome-wide linkage analysis suggested a putative disease gene in an 11.3-Mb region on chromosome 7p15-21.1 with a multipoint LOD score of 2.0.

CONCLUSIONS

The findings in this family further demonstrate genetic heterogeneity in familial autosomal dominant late-onset PD.

Eye movement disorders are different in Parkin-linked and idiopathic early-onset PD

OBJECTIVES

Parkin gene mutations are the most common cause of early-onset parkinsonism. Patients with Parkin mutations may be clinically indistinguishable from patients with idiopathic early-onset Parkinson disease (EOPD) without Parkin mutations. Eye movement disorders have been shown to differentiate parkinsonian syndromes, but have never been systematically studied in Parkin mutation carriers.

METHODS

Eye movements were recorded in symptomatic (n = 9) and asymptomatic Parkin mutation carriers (n = 13), patients with idiopathic EOPD (n = 14), and age-matched control subjects (n = 27) during established oculomotor tasks.

RESULTS

Both patients with EOPD and symptomatic Parkin mutation carriers showed hypometric prosaccades toward visual stimuli, as well as deficits in suppressing reflexive saccades toward unintended targets (antisaccade task). When directing gaze toward memorized target positions, patients with EOPD exhibited hypometric saccades, whereas symptomatic Parkin mutation carriers showed normal saccades. In contrast to patients with EOPD, the symptomatic Parkin mutation carriers showed impaired tracking of a moving target (reduced smooth pursuit gain). The asymptomatic Parkin mutation carriers did not differ from healthy control subjects in any of the tasks.

CONCLUSIONS

Although clinically similarly affected, symptomatic Parkin mutation carriers and patients with idiopathic EOPD differed in several oculomotor tasks. This finding may point to distinct anatomic structures underlying either condition: dysfunctions of cortical areas involved in smooth pursuit (V5, frontal eye field) in Parkin-linked parkinsonism vs greater impairment of basal ganglia circuits in idiopathic Parkinson disease.

Vergence deficits in patients with cerebellar lesions

The cerebellum is part of the cortico-ponto-cerebellar circuit for conjugate eye movements. Recent animal data suggest an additional role of the cerebellum for the control of binocular alignment and disconjugate, i.e. vergence eye movements. The latter is separated into two different components: fast vergence (to step targets) and slow vergence (to ramp and sinusoidal targets). The aim of this study was to investigate whether circumscribed cerebellar lesions affect these dynamic vergence eye movements. Disconjugate fast and slow vergence, conjugate smooth pursuit and saccades were binocularly recorded by a scleral search coil system in 20 patients with acute cerebellar lesions (all ischemic strokes except for one) and 20 age-matched healthy controls. Patients showed impairment of slow vergence while fast vergence was unaffected. Slow vergence gain to sinusoidal targets was significantly reduced, both in convergence and divergence direction. Divergence but not convergence velocity to ramp targets was reduced. Conjugate smooth pursuit eye movements to sinusoidal and to step-ramp targets were impaired. Patients had saccadic hypometria. All defects were particularly expressed in patients with vermis lesions. In contrast to recent animal data fast vergence was not impaired in any of our patient subgroups. We conclude that (i) the human cerebellum, in particular the vermis, is involved in the processing of dynamic vergence eye movements and (ii) cerebellar lesions elicit dissociable effects on fast and slow vergence.

Distributed representations of the "preparatory set" in the frontal oculomotor system: a TMS study

Background

The generation of saccades is influenced by the level of "preparatory set activity" in cortical oculomotor areas. This preparatory activity can be examined using the gap-paradigm in which a temporal gap is introduced between the disappearance of a central fixation target and the appearance of an eccentric target.

Methods

Ten healthy subjects made horizontal pro- or antisaccades in response to lateralized cues after a gap period of 200 ms. Single-pulse transcranial magnetic stimulation (TMS) was applied to the dorsolateral prefrontal cortex (DLPFC), frontal eye field (FEF), or supplementary eye field (SEF) of the right hemisphere 100 or 200 ms after the disappearance of the fixation point. Saccade latencies were measured to probe the disruptive effect of TMS on saccade preparation. In six individuals, we gave realistic sham TMS during the gap period to mimic auditory and somatosensory stimulation without stimulating the cortex.

Results

TMS to DLPFC, FEF, or SEF increased the latencies of contraversive pro- and antisaccades. This TMS-induced delay of saccade initiation was particularly evident in conditions with a relatively high level of preparatory set activity: The increase in saccade latency was more pronounced at the end of the gap period and when participants prepared for prosaccades rather than antisaccades. Although the "lesion effect" of TMS was stronger with prefrontal TMS, TMS to FEF or SEF also interfered with the initiation of saccades. The delay in saccade onset induced by real TMS was not caused by non-specific effects because sham stimulation shortened the latencies of contra- and ipsiversive anti-saccades, presumably due to intersensory facilitation.

Conclusion

Our results are compatible with the view that the "preparatory set" for contraversive saccades is represented in a distributed cortical network, including the contralateral DLPFC, FEF and SEF.

Transcranial sonography findings in a large family with homozygous and heterozygous PINK1 mutations

OBJECTIVE

To investigate substantia nigra (SN) echogenicity in members of a family with homozygous and heterozygous PTEN induced kinase (PINK1) mutations with or without signs of Parkinson's disease (PD).

METHODS

Transcranial sonography (TCS) was used to investigate 20 members of a family with PINK1 mutations, including four homozygous and 11 heterozygous mutation carriers and five individuals with no mutation. For comparison, a healthy control group of 18 subjects without a positive family history of PD (control group) and a healthy control group of 15 subjects with a positive family history of sporadic PD (relative group) were investigated. For statistical analysis, the larger area of the two SNs echogenicity (aSNmax) of each individual was selected.

RESULTS

A significantly increased aSNmax was found for all subgroups compared with the control group. The group of homozygous carriers of a PINK1 mutation had a significantly increased aSNmax compared with all of the other subgroups, except the group of heterozygous mutation carriers.

CONCLUSIONS

These findings in carriers of a PINK1 mutation are comparable with those in carriers of Parkin mutations and non-genetic PD. The increased aSNmax in family members without a mutation suggests an additional contributing factor independent of the PINK1 mutation that may also play a role in relatives of patients with sporadic PD.

fMRI evidence for sensorimotor transformations in human cortex during smooth pursuit eye movements

Smooth pursuit eye movements (SP) are driven by moving objects. The pursuit system processes the visual input signals and transforms this information into an oculomotor output signal. Despite the object's movement on the retina and the eyes' movement in the head, we are able to locate the object in space implying coordinate transformations from retinal to head and space coordinates. To test for the visual and oculomotor components of SP and the possible transformation sites, we investigated three experimental conditions: (I) fixation of a stationary target with a second target moving across the retina (visual), (II) pursuit of the moving target with the second target moving in phase (oculomotor), (III) pursuit of the moving target with the second target remaining stationary (visuo-oculomotor). Precise eye movement data were simultaneously measured with the fMRI data. Visual components of activation during SP were located in the motion-sensitive, temporo-parieto-occipital region MT+ and the right posterior parietal cortex (PPC). Motor components comprised more widespread activation in these regions and additional activations in the frontal and supplementary eye fields (FEF, SEF), the cingulate gyrus and precuneus. The combined visuo-oculomotor stimulus revealed additional activation in the putamen. Possible transformation sites were found in MT+ and PPC. The MT+ activation evoked by the motion of a single visual dot was very localized, while the activation of the same single dot motion driving the eye was rather extended across MT+. The eye movement information appeared to be dispersed across the visual map of MT+. This could be interpreted as a transfer of the one-dimensional eye movement information into the two-dimensional visual map. Potentially, the dispersed information could be used to remap MT+ to space coordinates rather than retinal coordinates and to provide the basis for a motor output control. A similar interpretation holds for our results in the PPC region.

Eye movement abnormalities in spinocerebellar ataxia type 17 (SCA17)

BACKGROUND

Spinocerebellar ataxia type 17 (SCA17) is associated with an expansion of CAG/CAA trinucleotide repeats in the gene encoding the TATA-binding protein. In this quantitative characterization of eye movements in SCA17 mutation carriers, we investigated whether eye movement abnormalities originate from multiple lesion sites as suggested by their phenotypic heterogeneity.

METHODS

Eye movements (saccades, smooth pursuit) of 15 SCA17 mutation carriers (mean age 36.9 years, range 20 to 54 years; mean disease duration 7.3 years, range 0 to 20 years; 2 clinically unaffected, 13 affected) were compared with 15 age-matched control subjects using the video-based two-dimensional EYELINK II system.

RESULTS

Smooth pursuit initiation (step-ramp paradigm) and maintenance were strongly impaired, i.e., pursuit latency was increased and acceleration decreased, whereas latency and position error of the first catch-up saccade were normal. Visually guided saccades were hypometric but had normal velocities. Gaze-evoked nystagmus was found in one-third of the mutation carriers, including downbeat and rebound nystagmus. There was a pathologic increase in error rates of antisaccades (52%) and memory-guided saccades (42%). Oculomotor disorders were not correlated with repeat length. Smooth pursuit impairment and saccadic disorders increased with disease duration.

CONCLUSIONS

Several oculomotor deficits of spinocerebellar ataxia type 17 (SCA17) mutation carriers are compatible with cerebellar degeneration. This is consistent with histopathologic and imaging (morphometric) data. In contrast, increased error rates in antisaccades and memory-guided saccades point to a deficient frontal inhibition of reflexive movements, which is probably best explained by cortical dysfunction and may be related to other phenotypic SCA17 signs, e.g., dementia and parkinsonism.