Somatosensory evoked potential findings in ankylosing spondylitis

Altered cerebral blood flow patterns in ankylosing spondylitis: A three-dimensional pseudo-continuous arterial spin labeling study

Objective

This study aimed to detect the cerebral blood flow (CBF) values changes in patients with ankylosing spondylitis (AS) and to evaluate the correlation between the CBF values and the specific clinical characteristics.

Materials and methods

Forty-eight patients with AS (43 male and 5 female) and 42 healthy controls (HCs) (38 male and 4 female) were recruited. Three-dimensional pseudo-continuous arterial spin labeling (3D-pCASL) was performed on a 3.0T magnetic resonance imaging (MRI). CBF values were obtained on the Philips post-processing workstation based on arterial spin labeling (ASL) data. The two-sample t-test was used to compare CBF differences. The correlation between CBF values and specific clinical characteristics of AS was evaluated.

Results

The AS group showed increased CBF values in the right precentral gyrus, the left inferior frontal gyrus, and the left temporal pole compared with HCs the AS group also showed decreased CBF values in the left precuneus and the left superior occipital gyrus compared with HCs. There were no significant correlations between the CBF values and the clinical characteristics including total back pain (TBP), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).

Conclusion

Patients with AS displayed CBF changes compared with HCs using 3D-PCASL. These results may enhance our understanding of the neural substrates of AS and provide evidence of AS-related neurological impairment.

The effects of head posture on nerve conduction studies in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease which effects cervical posture of patients. The aim of this study was to evaluate AS patients according to the degree of cervical disorder and was evaluate them electrophysiologically, functionality, and disease parameters. Our study comprised 64 AS patients and 30 healthy controls. The head posture of patients was evaluated by craniovertebral angle (CVA) measurement. Nerve conduction of bilateral median, radial, ulnar, and medial antebrachial cutaneous (MAC) nerves were studied in all patients. The most important nerve conduction differences in AS patients who have severe forward head posture (FHP) were decrease in sensory nerve action potential (SNAP) amplitude and compound muscle action potential amplitudes of median nerves, a decrease in the SNAP amplitude of ulnar nerves, a delay in the F response latency of ulnar nerves, and prolongation in the SNAP latency of the MAC nerve. The FHP disorder that develops in AS patients may have electro physiological effects, similar to those of thoracic outlet syndrome In addition, the functional status of these patients is worsened as severity of FHP increases.

Neuropathic component of low back pain in patients with ankylosing spondylitis

OBJECTIVE

The aim of this cross sectional study was to evaluate frequency of neuropathic back pain in ankylosing spondylitis (AS) patients and to determine the relation with disease variables and occurrence of neuropathic pain.

METHODS

Fifty-eight AS patients who were not having any comorbid disease and/or using drugs that would cause neuropathy, were recruited to the study. Demographic properties and clinical characteristics (functional status and disease activity assessed by BASFI and BASDAI respectively, ESR, CRP) and quality of life determined by AS quality of life-QoL questionnaire, were recorded. The neuropathic property of back pain was assessed by both Leeds Assessment of Neuropathic symptoms and signs (LANSS) and Douleur Neuropathique 4 (DN4) scales.

RESULTS

58 AS patients (17 female, 41 male) with a mean age of 45 ± 18 years were included. 33 patients (56.9%) and 31 patients (53.4%) were defined as having neuropathic pain depending on the LANSS (scores > 12) and DN4 (scores > 4) questionnaire scores respectively. The mean score of LANSS scale was correlated with ASQoL, BASFI, BASDAI, and DN4; and the mean score of DN4 scale was correlated with ASQoL, BASFI and LANSS. The mean levels of BASFI and ASQoL scores were significantly higher in patients having neuropathic pain than in patients not having (p < .05).

CONCLUSION

Neuropathic pain is common and determined in more than half of the patients with AS and related with functional status and quality of life. Diagnosis and treatment of neuropathic pain are warranted in order to increase functional ability and quality of life in patients suffering from AS.

Cerebral functional deficits in patients with ankylosing spondylitis- an fMRI study

Neurological impairment plays an important role in the development of Ankylosing spondylitis (AS). Early diagnosis and detection of it may stop the progress of neurological complications and improve the quality of patients' lives greatly. Somatosensory evoked potential (SSEP) and magnetic motor evoked potentials (MEP) have been proved useful to detect neurological impairments of AS. This study aimed to investigate the cerebral function deficits of AS using functional MRI technology. Twenty seven patients with AS and 28 control subjects were included in this study. All of them underwent structural MRI and resting state-functional MRI (rs-fMRI) scanning. Comparisons of amplitude of low frequency fluctuations (ALFF) of rs-fMRI signals between AS patients and normal controls were performed using two sample t-tests. To examine functional connectivity within the groups, one-sample t tests were performed on the individual z-value maps. The z values were compared between the two groups using two-sample t test. Partial correlations between rs-fMRI measures (ALFF and functional connectivity) of the brain regions which showed group difference and clinical results including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score, the serum high-sensitivity C-reactive protein (hsCRP), and the erythrocyte sedimentation rate (ESR) were analyzed for AS patients. Compared with normal controls, the AS patients exhibited significant lower ALFF in the left medial frontal gyrus, the right precentral gyrus and the right posterior cingulate, while higher ALFF in the left cerebellum anterior lobe, the left middle temporal gyrus, the left superior occipital gyrus, the left postcentral gyrus and the right precuneus. AS patients showed widespread brain connectivity alterations. Functional connectivity strength of the left precuneus and the left middle temporal gyrus were closely correlated with the the BASDAI scores, ESR and hsCRP in AS patients. Our results enhance the understanding of the pathomechanism of AS and suggest that Rs-fMRI may be a helpful tool in the clinical detection and evaluation of neurological impairment in AS.

The cutoff value of ossification of posterior longitudinal ligament (OPLL) for early diagnosis of myelopathy using somatosensory evoked potential in cervical OPLL patients

STUDY DESIGN

Retrospective study.

OBJECTIVES

The objective of this study was to find out whether ossification of posterior longitudinal ligament (OPLL) characteristics, including size, shape and subtype, can be used to diagnose myelopathy using somatosensory evoked potential (SEP) in cervical OPLL patients.

SETTING

Yonsei University College of Medicine, Seoul, Korea.

METHODS

We retrospectively reviewed the medical records of 153 cervical OPLL patients who underwent SEP study. OPLL anterior-posterior (AP) diameter, area and involved longitudinal vertebral level were measured. OPLL was classified into subtypes according to longitudinal continuity and shape. Correlation analysis and receiver operating curve were used.

RESULTS

Tibial SEP latency was significantly correlated with OPLL AP diameter (P=0.001), diameter occupying ratio (P=0.019), area (P=0.007), area occupying ratio (P=0.008), involved longitudinal vertebral level (P=0.028) and space available for the spinal cord (P=0.019). The cutoff values that were diagnostic for SEP prolongation suggesting myelopathy were 4.91 mm for OPLL AP diameter, 6.02 mm for space available for the spinal cord, 44.5% for diameter occupying ratio, 63.4 mm² for area, 36.1% for area occupying ratio and level 2 for the involved longitudinal vertebral level.

CONCLUSIONS

Our results revealed that tibial SEP latency was significantly correlated with OPLL size and suggested cutoff values of OPLL diameter (4.91 mm, 44.5%) and area (63.4 mm², 36.1%) for early diagnosis of myelopathy. These results can help to establish treatment plans.