Sensitivity of three median-to-ulnar comparative tests in diagnosis of mild carpal tunnel syndrome

We studied 193 hands of 113 patients referred for typical carpal tunnel syndrome (CTS). Ninety-five (49%) hands had normal median distal motor latency (≤4.2 ms) and normal or borderline sensory conduction velocity from digit 2 stimulation (≥45 m/s). In these cases we performed three median to ulnar comparative tests: (1) difference between median and ulnar distal motor latencies recorded from the second lumbrical and interossei muscles (2L-INT); (2) difference between median and ulnar sensory latencies from digit 4 stimulation (D4M-D4U); and (3) difference between median and ulnar mixed nerve latencies from palmar stimulation (PM-PU). The 2L-INT difference was ≥0.6 ms in 10% of hands. PM-PU and D4M-D4U were ≥0.5 ms in 56% and 77% of hands, respectively. The greater sensitivity of D4M-D4U might be explained by the funicular topography and consequent greater susceptibility to compression of the cutaneous fibers from the third interspace which, at the distal carpal tunnel, are clumped superficially in the anteroulnar portion of the median nerve just beneath the transverse ligament. © 1993 John Wiley & Sons, Inc.     

Diagnostic specificity of sensory and motor nerve conduction variables in early detection of carpal tunnel syndrome

Summary In the carpal tunnel syndrome (CTS) sensory nerve conduction is more sensitive than motor conduction. However, 8%–25% of the sensory distal latencies in symptomatic hands may still be normal. A systematic study was made of the median, ulnar and radial orthodromic nerve conduction velocities (SNCV) stimulating each of the fingers separately. Four SNCVs from the median nerve, two SNCVs from the ulnar nerve and one from the radial nerve were obtained, and the ratio of the median to radial SNCV and the ratios of the median and ulnar SNCVs were estimated. The significance of these parameters in the diagnosis of the CTS was studied, and a rapid technique for the screening of nerve entrapment in the initial stages of the disease is proposed. Three hundred and seventy-five symptomatic hands were examined. Seventy-five hands showed normal distal latency, in which cases, however, the SNCV of the ring finger was always outside the normal range, while the SNCVs of the thumb, index and middle fingers were abnormal in 64%, 80% and 92% of cases respectively. The amplitudes of the sensory responses were the least sensitive of the parameters studied. Our results suggest that a study of the median nerve digital branch to the ring finger may be of value in providing an easily performed and rapid technique for screening an early median nerve entrapment at the wrist.     

环指感觉神经感觉传导速度在轻度腕管综合征诊断中的应用

目的 寻找诊断轻度腕管综合征(CTS)敏感的电生理检查方法。方法 临床症状、体征符合CTS,正中神经运动末端潜伏期正常的患者19例(29侧)和年龄性别相匹配的健康对照组23名(25侧),采用顺向性感觉神经传导速度(SCV)测定法分别测定环指(指4)正中神经和尺神经SCV,中指(指3)正中神经SCV。结果 环指尺神经SCV>45.2 m/s,正中神经SCV<44.1 m/s,和(或)尺神经SCV与正中神经SCV差值>8.1 m/s(x+σx),考虑符合CTS诊断。CTS组中指正中神经SCV测定异常率为66％,环指为76％,环指正中神经与尺神经SCV差值异常率为93％。环指刺激在8例(14侧)患者腕部正中神经处记录到双峰电位,但对照组均未见。结论 比较环指正中神经和尺神经SCV在鉴别轻度CTS方面是敏感的方法之一,在怀疑CTS时,该项检查可作为常规的电生理检查方法。     

Orthodromic median and ulnar fourth digit sensory conductions in mild carpal tunnel syndrome

Because the fourth digit (D4) has a dual innervation, median and ulnar D4 sensory conduction velocity (SCV) comparison may be useful in diagnosing the carpal tunnel syndrome (CTS). We studied 50 control hands and 41 hands with recent onset symptoms and signs of CTS but normal median distal motor latency and normal SCV from the second digit (D2). In CTS, D4 SCV was significantly slower than D2 SCV and D4 median and ulnar sensory conduction difference was abnormal in 38 hands (92%). In 36 CTS hands (87%), but in no control hand, a double peak potential could be recorded over the median after D4 stimulation providing an immediate visual confirmation of the diagnosis of CTS. Comparing median and ulnar D4 SCV is a very sensitive method to detect early or mild CTS and should be used whenever conventional electrodiagnostic studies are normal or borderline.     

Ulnar nerve conduction abnormalities in carpal tunnel syndrome

Introduction: The aim of this study was to verify the involvement of ulnar nerve fibers in cases of carpal tunnel syndrome (CTS) and investigate the correlation between ulnar nerve conduction parameters and extra‐median spread of symptoms. Methods: Electrophysiological studies were conducted in 93 CTS and 76 control hands. Patients were analyzed with regard to symptoms in the fifth finger. Results: In the CTS cases, ulnar distal motor latency (DML) and distal sensory latency (DSL) were significantly longer, and amplitudes were lower than in controls. Increased median nerve DML correlated with increased ulnar nerve DSL and decreased sensory amplitudes and conduction velocities (SCVs). In cases with symptoms in the fifth finger, ulnar nerve SCVs and amplitudes were lower than in patients without symptoms. Conclusions: Pathological processes leading to median neuropathy in CTS may affect ulnar nerve motor and sensory fibers in the Guyon canal. This may explain the extra‐median spread of sensory symptoms in CTS patients. Muscle Nerve 44: 352–357, 2011     

Focal sensory nerve abnormalities in patients with amyotrophic lateral sclerosis

Slowing of sensory nerve conduction is an unexplained finding in patients with sporadic amyotrophic lateral sclerosis (ALS). To study the frequency of these abnormalities and to study if a predisposition to the development of entrapment neuropathies is causal, 23 patients with definite ALS and 23 age-matched healthy volunteers were investigated prospectively. Antidromic sensory and motor nerve conduction velocities (NCVs) were measured in ulnar and median nerves. Median sensory NCV was abnormally low in three patients if compared with the lower limit of the control group; and median sensory NCV was abnormally low in nine patients (six right, eight left hands) if compared with ipsilateral ulnar sensory NCV. Sensory nerve conduction data did not correlate with clinical findings, such as forearm weakness or usage of canes. Motor nerve conduction data did not correlate with sensory nerve conduction data, with the exception of distal motor latency of right median nerves, which correlated with right median sensory NCV. Our findings show how affection of sensory fibers of distal segments of median nerves can be detected in individual patients with ALS. Nerve entrapment may contribute to this affection, but it is not the only cause. This should be considered in discussions about diagnostic criteria for ALS.     

Sensory nerve action potentials in the evaluation of diabetic polyneuropathy]

In order to clarify the suitability of sensory nerve action potential(SNAP) in the evaluation of diabetic polyneuropathy, we studied measurements of SNAPs in the median, ulnar and sural nerves. Subjects were 253 patients with non-insulin dependent diabetes mellitus; 167 men and 86 women, aged 58.2 +/- 12.8(mean +/- SD) years old. Their diabetic history was 10.2 +/- 8.6 years. SNAPs were recorded antidromically from index finger, little finger and lateral to the Achilles tendon, respectively. Twenty-eight patients, in whom any one of the SNAPs couldn't be obtained, were already excluded from this study. The polyneuropathy index (PNI) was calculated from 12 indices concerning to the velocity or long distance latency in motor nerve conduction studies of 4 nerves. The PNI is known to be an excellent index to express the degree of diabetic polyneuropathy. Amplitude and conduction velocity in each nerve was 28.6 +/- 15.6 microV and 46.2 +/- 7.4 m/sec in the median nerve, 26.7 +/- 15.8 microV and 47.0 +/- 6.5 m/sec in the ulnar nerve, 13.1 +/- 6.5 microV and 43.1 +/- 6.0 m/sec in the sural nerve, respectively. The coefficient of correlation of the measurements between median and ulnar nerves was larger than other assortment of nerves. The coefficient of correlation of each measurement with PNI was around 0.40 in the amplitude and around 0.55 in the conduction velocity. Nevertheless, the mean value of the 3 nerves had a higher coefficient of correlation with PNI; 0.48 in the amplitude and 0.60 in the conduction velocity. SNAP measurements of a single nerve are often largely affected by the inter-individual differences, inter-nerve differences or measuring errors. But the mean value of the 3 nerves will be better in exploring the degree of diabetic polyneuropathy. Evaluation of diabetic polyneuropathy by SNAPs will be best achieved by using the mean value of these 3 nerves.     

Study on the latency difference between compound muscle and sensory nerve action potentials]

In motor nerve conduction studies compound muscle action potentials (CMAPs) appear later than sensory nerve action potentials (SNAPs). This time lag originates from the conduction delay at the distal motor axon, neuromuscular transmission time and muscle action potential induction time. To investigate the latency difference between CMAPs and SNAPs we studied 46 healthy individuals, 46 patients with diabetes mellitus and 33 patients with carpal tunnel syndrome, using the lumbrical and interossei recording method. In this method the recording active electrode was placed on the 2nd lumbrical muscle and the reference electrode on the proximal palmar aspect of the index finger. Supramaximal stimulation was given to the median or ulnar nerve trunk at 9-cm proximal to the recording active electrode. The CMAP from the 2nd lumbrical muscle (L) and the SNAP from the digital nerve (N) were recorded after median nerve stimulation, and the CMAP from the 2nd interossei muscles (I) was recorded after ulnar nerve stimulation. The residual latency, which is arbitrary defined as the latency difference (L-N) in this study, was 1.38 +/- 0.15 (mean +/- SD) msec in healthy individuals. About 1 msec of the residual latency is regarded as the time for neuromuscular transmission and the time to evoke muscle activities. Thus, the conduction delay at the distal motor axon was calculated as about 0.4 msec in healthy individuals. The residual latency was relatively constant in 29 diabetic patients without conduction delay across the carpal tunnel, which was defined by the latency difference (L-I) < or = 0.4 msec. Their sensory nerve conduction velocities (calculated from N latency) were always above 40 m/sec. On the other hand in diabetic patients with conduction delay across the carpal tunnel, which was defined by the latency difference (L-I) > 0.4 msec, the residual latency gradually increased as the sensory nerve conduction velocity decreased. Their sensory nerve conduction velocities were mostly less than 40 m/sec. The similar relationship was observed in patients with carpal tunnel syndrome without diabetes mellitus. We consider that the diabetic neuropathy alone doesn't cause the increase of the residual latency. Instead, severe conduction delay across the carpal tunnel decreases the N velocity and increases the residual latency. We can also regard the relationship between the latency difference (L-N) and N velocity as being in inverse proportion. Perhaps the increase of the residual latency was simply caused by the proportional decrease in the conduction velocity at the distal motor axon, not by the special mechanism concerning to the carpal tunnel syndrome. This paper presented the electrophysiological changes seen in the distal segment secondary to the proximal entrapment.     

Multiple measures of axonal excitability in peripheral sensory nerves: an in vivo rat model

Excitability measurements on human motor and sensory nerves have provided new insights into axonal membrane changes in peripheral nerve disorders. The aim of this study was to establish an in vivo rat preparation suitable for threshold tracking of sensory nerve action potentials (SNAPs) to model clinical sensory nerve excitability studies. In Sprague-Dawley rats anesthetized with ketamine and xylazine, current stimuli were applied to the base of the tail and SNAPs recorded from distal needle electrodes. Multiple excitability data were obtained as previously described for human nerves and compared to recordings from the motor tail axons and to sensory recordings from human median and ulnar nerves. The pattern of excitability changes in rats was broadly similar to that in humans, although some parameters differed significantly. Individual recordings were stable for at least 3 h. These data show that the rat tail enables excitability properties of sensory as well as motor axons to be studied experimentally, e.g., in models of nerve disease and during pharmacological interventions.     

Clinical validation of antidromic stimulation of the ring finger in early electrodiagnosis of mild carpal tunnel syndrome.

Median and ulnar sensory distal latencies were measured antidromically on the fourth finger in 158 patients (224 hands) with suspected carpal tunnel syndrome (CTS), in 60 normal subjects (100 hands), and in 30 patients (30 hands) who suffered from paresthesiae due to a cervical spondylotic radiculopathy (CSR). The difference between these 2 latencies was less than 0.4 msec in all normals and patients with CSR, while in all of the patients with CTS it was more than 0.5 msec. Median sensory nerve conduction was significantly slower for the fourth than for the second finger in the CTS group, but not in controls. The difference between median and ulnar sensory distal latencies on the fourth finger proved to be the most sensitive of the tested parameters and was the only abnormal one in 20% of the clinically affected hands. The ring finger technique is a quick and easy procedure, which should be recommended in the early diagnosis of mild CTS.     

Ulnar sensory nerve impairment at the wrist in carpal tunnel syndrome

In previous studies, changes in impulse transmission of ulnar motor axons have been documented in patients with carpal tunnel syndrome (CTS). We examined ulnar sensory conduction in 144 CTS hands. In particular, conduction parameters of the dorsal ulnar cutaneous branch (DUC) running outside Guyon's canal were compared with those of the superficial sensory branches (U4 and U5) passing through the canal. U4 and U5 response amplitudes and U5 conduction velocity were significantly lower than in controls. Conduction parameters of the DUC were similar in both groups. Patients with more severely impaired median conduction had smaller ulnar sensory action potentials. We propose that the ulnar nerve may be subject to compression in Guyon's canal as a consequence of high pressure in the carpal tunnel of CTS patients. This may provide insights into the mechanisms underlying extra-median spread of sensory symptoms in CTS patients.     

Spread of the radial SNAP: a pitfall in the diagnosis of carpal tunnel syndrome using standard orthodromic sensory conduction study.

OBJECTIVE: To investigate the occurrence of the spread of the radial sensory nerve action potential (SNAP) among patients with carpal tunnel syndrome (CTS) during standard median orthodromic sensory conduction study (SCS) using index finger stimulation. METHODS: We prospectively examined 74 hands in 56 CTS patients. We stimulated the index finger using ring electrodes. SNAPs were recorded at wrist over median and radial nerves. RESULTS: A spread of radial SNAP was clearly identified over the median nerve despite its small amplitude, in 72/74 hands during stimulation of the base of the index finger. In hands with delayed median SNAP, two peaks were observed; however in hands with absence of genuine median SNAP, only one peak of the spread was noticed. The proximal interphalangeal joint (PIP) stimulation still elicited an identifiable spread in 47/74 hands. CONCLUSION: This spread phenomenon is a previously undescribed pitfall during the standard median orthodromic SCS, frequently occurring in CTS patients. SIGNIFICANCE: In severe CTS cases, one may make wrong conclusion of normal median sensory latency if unaware of this pitfall.     

Effects of interelectrode separation in sensory nerve conduction studies]

Sensory nerve action potentials (SNAPs) obtained by conventional sensory nerve conduction studies are greatly influenced by the distance between exploring and reference electrodes. Changes in SNAPs were investigated in 12 healthy median nerves using the orthodromic and antidromic sensory nerve conduction studies with 1-cm, 2-cm, 3-cm, 4-cm, and 5-cm of interelectrode distances. Peak-to-peak (orthodromic) or baseline-to-peak (antidromic) amplitudes and durations between the positive peaks were measured and each value was expressed as a ratio to the recording of 1-cm of interelectrode distance. SNAPs with maximum amplitude were obtained by more than 3-cm of interelectrode distance. Duration of SNAP was increased by an increase of interelectrode distance. Change in amplitude along with the interelectrode distance was larger in the orthodromic method than in the antidromic method. Contrariwise, change in duration was larger in the antidromic method. SNAPs with long duration had a gently sloping configuration, and each peak tended to be indistinct. So, 3-cm of active and reference interelectrode separation should be recommended in performing sensory nerve conduction studies between wrist and finger, because maximum amplitude and clear visualization of peaks are available.     

Medial thenar recording in normal subjects and carpal tunnel syndrome.

OBJECTIVE: Since little is known about the involvement of median nerve fibres to the medial thenar eminence in CTS, we determine the consistency of a motor response derived from a medial thenar motor (MTM) site. We then compare sensitivity and specificity of this novel site with other nerve conduction parameters in supporting a diagnosis of CTS. METHODS: The motor responses over the MTM with ulnar and median stimulation were determined in healthy subjects and patients with CTS. Sensitivity and specificity of 4 motor techniques (Abductor Pollicis Brevis (APB) and median MTM latency, 2nd Lumbricales to Interossei latency difference (2-LINT), APB to Adductor Digiti Minimi (ADM) latency difference, median MTM to ulnar MTM latency difference) and the median sensory distal latency in confirming CTS were calculated using the ROC method. RESULTS: 132 hands (68 CTS, 64 controls) were examined. All but one median and ulnar nerve stimulation (both in patients with CTS) resulted in negative MTM compound muscle action potentials. Sensitivity and specificity in diagnosing CTS were 79/97% (APB) 90/98% (median MTM latency), 88/97% (2-LINT), 85/97% (APB to ADM latency difference) and 75/95% (median MTM to ulnar MTM latency difference). Median sensory latency showed 89% sensitivity and 97% specificity. CONCLUSIONS: Median and ulnar stimulation results in consistent motor responses at the medial thenar site. Median distal motor latency to MTM is frequently abnormal in CTS showing similar sensitivity and specificity to 2-LINT and median distal sensory latency. SIGNIFICANCE: The MTM site shows consistent responses to both median and ulnar stimulation. MTM distal latency can be considered a useful site for supporting a diagnosis of CTS.     

第二蚓状肌-骨间肌记录法在腕管综合征的诊断价值研究

目的探讨第二蚓状肌-骨间肌记录法在不同程度腕管综合征(carpal tunnel syndrome;CTS)中的诊断价值。方法以符合纳入标准的CTS患者44例(56只患手)为病例组,年龄、性别匹配的30例健康志愿者的非利手为对照组。表面电极刺激和记录,分别进行正中、尺神经的运动和感觉传导检测。主要参数包括,(1)掌-拇短展肌的末端运动潜伏时(DML)、腕-拇短展肌DML(APB-DML)、腕-掌段运动传导速度(wpMCV),以及腕-食指末端感觉潜伏时(DSL)、感觉传导速度(SCV);(2)腕-小指展肌DML、腕-第二骨间肌DML;(3)腕-环指正中/尺神经末端感觉潜伏时的差值(dDSL);(4)腕-第二蚓状肌DML(2L-DML)及其与腕-第二骨间肌DML的差值(2LI-DML)。根据腕-拇短展肌DML以及腕-食指SCV,将CTS患者分为轻、中和重度组。结果在44例患者56只患手中轻度CTS19肢,中度22肢,重度15肢;其中7例CTS患者合并下肢周围神经病。与对照组相比,3个病例组的APB-DML延长、wpMCV减慢、dDSL增大、2L-DML延长、2LI-DML增大,均有统计学差异(P0.01)。在轻度组以及中度组2LI-DML诊断的敏感性与APB-DML、wpM-CV、dDSL无明显差异(P0.05);在重度组,2LI-DML诊断的敏感性与APB-DML、wpMCV无差异(P0.05),与dDSL的差异有显著性(χ2=7.03,P0.05)。结论第二蚓状肌-骨间肌记录法可有效检出各种程度的CTS,在重度CTS尤其是合并多发性神经病者,则是很有价值的检测方法。     

Comparison of median and ulnar sensory nerve action potentials in the diagnosis of the carpal tunnel syndrome

Recording of median and ulnar digital sensory nerve action potentials in normal subjects showed that the ratio of the median (index finger) to ulnar (little finger) potential amplitude was consistently greater than one. In 15 patients with the carpal tunnel syndrome (seven bilateral) this ratio was found to be less than one for all but two of the 22 clinically affected hands, including three of the four hands with a normal motor latency to threshold stimulation and four of the five hands with a normal sensory conduction. It is concluded that the estimation of the ratio of the median to ulnar sensory potential amplitude is a sensitive test in the diagnosis of the carpal tunnel syndrome and is particularly useful in those patients who show a normal motor latency and sensory conduction.     

Ulnar nerve entrapment at wrist associated with carpal tunnel syndrome.

In this study, ulnar nerve entrapments at the wrist were investigated using nerve conduction studies in cases with established diagnosis of carpal tunnel syndrome (CTS). Cases with cervical radiculopathy and polyneuropathy as well as patients with ulnar nerve entrapment at elbow were excluded from the study. Fifty-three cases (46 females, seven males) whose ages ranged between 20 and 72 years (mean: 49.31 +/- 13.78) were evaluated. Among 53 cases, 12 (22.6%) bilateral and 41 (77.3%) unilateral CTS were detected. Totally 65 wrists evaluated and prolongation of median nerve wrist-3rd digit distal sensory latencies (DSL; N: 59; 90.7%) and wrist-abductor pollicis brevis distal motor latencies (N: 48; 73.8%) were seen. In six wrists, diagnoses were established with the detection of an increase in the differences between wrist-4th digit DSL of median and ulnar nerve. This test was used if other test results were in normal limits. Prolongation of ulnar nerve wrist-5th digit DSL were found in 12 wrists (18.4%) in cases with CTS. Among these 12 wrists mild (N: 2), moderate (N: 7) and severe (N: 3) CTS were detected. Ulnar nerve motor conduction studies provided normal results. In conclusion, we are in the opinion that for the detection of associated ulnar nerve wrist entrapments, ulnar nerve conduction studies paying special attention to DSL convey importance in established cases with CTS.     

Ulnar nerve impairment at the wrist does not contribute to extramedian sensory symptoms in carpal tunnel syndrome

ObjectiveExtramedian spread of sensory symptoms is frequent in carpal tunnel syndrome (CTS) but its mechanisms are unclear. We explored the possible role of subtle ulnar nerve abnormalities in the pathogenesis of extramedian symptoms.MethodsWe recruited 350 CTS patients. After selection, 143 patients (225 hands) were included. The hand symptoms distribution was graded with a diagram into median (MED) and extramedian (EXTRAMED) pattern. We tested the correlation of ulnar nerve conduction measures with the distribution and the severity of symptoms involving the ulnar territory. The clinical significance of ulnar nerve conduction findings was explored with quantitative sensory testing (QST).ResultsEXTRAMED distribution was found in 38.7% of hands. The ulnar neurographic measures were within normal values. Ulnar nerve sensory measures were significantly better in EXTRAMED vs MED hands and not significantly correlated to ulnar symptoms severity. Ulnar and median nerve sensory measures were significantly correlated. QST showed normal function of ulnar nerve Aβ-fibers.ConclusionsUlnar nerve sensory abnormalities do not contribute to the spread of sensory symptoms into the ulnar territory.SignificanceOur data favour the hypothesis that spinal and supraspinal neuroplastic changes may underlie extramedian spread of symptoms in CTS.     

Comparison of median and radial nerve sensory latencies in the electrophysiological diagnosis of carpal tunnel syndrome

An electrophysiological diagnosis of carpal tunnel syndrome (CTS) was made on the basis of the median sensory nerve action potential (SNAP) alone in 79 of 161 (49.1%) symptomatic hands without electrophysiological evidence of a generalised peripheral neuropathy. Comparison of distal sensory latencies (DSLs) for the median and radial nerves yielded abnormal results in 17 of the remaining hands with normal median nerve DSLs, increasing the electrodiagnostic yield to 59.6%. Carpal tunnel decompression has been performed in seven of these hands, with abnormal intraoperative findings reported in two, while all improved clinically following surgery, substantiating the diagnosis of CTS. Although the technique described here would not appear to increase the electrodiagnostic yield more than comparison of DSLs for the median and ulnar nerves, which has been reported previously, it remains an effective, quick and simple procedure for increasing the sensitivity of the nerve conduction studies.     

Patterns of sensory nerve conduction abnormalities in Fisher syndrome: More predominant involvement of group Ia afferents than skin afferents

ObjectiveTo elucidate the features of sensory nerve involvement in Fisher syndrome (FS), this study extensively investigated sensory electrophysiology.MethodsIn 47 consecutive FS patients, results of sensory nerve conduction studies in the median, ulnar and sural nerves, soleus H-reflexes, and median or tibial somatosensory-evoked potentials (SEP) were reviewed. Because of the large effects of age on amplitude of sensory nerve action potentials (SNAP), we strictly defined reduction of SNAP amplitudes by using a nomogram which age and amplitude obtained from 87normal subjects.ResultsIn routine nerve conduction studies, SNAP amplitude was reduced only in 32% of the patients, and conduction velocity was decreased in 2%. In contrast, soleus H-reflexes were frequently absent or reduced (67%). SEPs were abnormal only in 17%.ConclusionsIn FS, absent soleus H-reflexes are the most frequent electrophysiologic abnormalities, whereas SNAPs amplitudes are rarely affected. The pattern is characterized by predominant involvement of group Ia afferents with relatively preserved cutaneous afferents without evidence suggestive of demyelination.SignificanceThe major targets of immune attack by anti-GQ1b antibodies in FS appear to be group Ia neurons in the dorsal root ganglia, and this is presumably responsible for ataxia and areflexia in FS.