Strokes mimicking peripheral nerve lesions

A scoping review on examination approaches for identifying tactile deficits at the upper extremity in individuals with stroke

PURPOSE

Accurate perception of tactile stimuli is essential for performing and learning activities of daily living. Through this scoping review, we sought to summarize existing examination approaches for identifying tactile deficits at the upper extremity in individuals with stroke. The goal was to identify current limitations and future research needs for designing more comprehensive examination tools.

METHODS

A scoping review was conducted in accordance with the Joanna Briggs Institute methodological framework and the PRISMA for Scoping Reviews (PRISMA-ScR) guidelines. A database search for tactile examination approaches at the upper extremity of individuals with stroke was conducted using Medline (Ovid), The Cochrane Library (Wiley), CINAHL Plus with Full Text (Ebsco), Scopus (Elsevier), PsycInfo (Ebsco), and Proquest Dissertations and Theses Global. Original research and review articles that involved adults (18 years or older) with stroke, and performed tactile examinations at the upper extremity were eligible for inclusion. Data items extracted from the selected articles included: if the examination was behavioral in nature and involved neuroimaging, the extent to which the arm participated during the examination, the number of possible outcomes of the examination, the type(s) of tactile stimulation equipment used, the location(s) along the arm examined, the peripheral nerves targeted for examination, and if any comparison was made with the non-paretic arm or with the arms of individuals who are neurotypical.

RESULTS

Twenty-two articles met the inclusion criteria and were accepted in this review. Most examination approaches were behavioral in nature and involved self-reporting of whether a tactile stimulus was felt while the arm remained passive (i.e., no volitional muscle activity). Typically, the number of possible outcomes with these behavioral approaches were limited (2-3), whereas the neuroimaging approaches had many more possible outcomes ( > 15 ). Tactile examinations were conducted mostly at the distal locations along the arm (finger or hand) without targeting any specific peripheral nerve. Although a majority of articles compared paretic and non-paretic arms, most did not compare outcomes to a control group of individuals who are neurotypical.

DISCUSSION

Our findings noted that most upper extremity tactile examinations are behavioral approaches, which are subjective in nature, lack adequate resolution, and are insufficient to identify the underlying neural mechanisms of tactile deficits. Also, most examinations are administered at distal locations of the upper extremity when the examinee's arm is relaxed (passive). Further research is needed to develop better tactile examination tools that combine behavioral responses and neurophysiological outcomes, and allow volitional tactile exploration. Approaches that include testing of multiple body locations/nerves along the upper extremity, provide higher resolution of outcomes, and consider normative comparisons with individuals who are neurotypical may provide a more comprehensive understanding of the tactile deficits occurring following a stroke.

Dissociative pseudo-ulnar sensory loss in a patient with a focal haemorrhage secondary to cerebral venous thrombosis - A case report

INTRODUCTION

Small cortical strokes can mimic weakness of peripheral nerve lesions. However, isolated sensory deficits involving the fingers due to cortical lesions are rare.

METHODS

We present a case of a 46 year old man with cerebral venous thrombosis, and a haemorrhage restricted to the postcentral gyrus, who reported numbness in an ulnar neuropathy-like distribution. Testing of somatosensory (SSEP) and pain-related evoked potential (PREP) was done, and the lesion location was mapped to the template brain.

RESULTS

The patient had impaired touch and pain but preserved proprioception. He had a normal SSEP response but a prolonged PREP. The lesion was mapped to Broadmann areas 1 and 3b of the postcentral gyrus.

DISCUSSION

Sensory cortical representation is such that, the ulnar fingers are medial, and the radial ones are lateral. Also, modality-specific organization is noted with tactile sensation being mapped to areas 1 and 3b, and proprioceptive sensation to area 3a and 2. Thus focal lesions involving the post central gyrus can have selective sensory loss over some fingers and can have selective impairment of some modalities.

CONCLUSIONS

We highlight the rare finding of an ulnar-like sensory loss in a patient with cerebral venous thrombosis and the dissociate nature of the sensory loss in isolated cortical lesions.

Open-loop and closed-loop control of posture: Stabilogram-diffusion analysis of center-of-pressure trajectories among people with stroke

Many people with stroke (PwS) demonstrate reduced balance and increased postural sway afterwards, which may ultimately lead to falls and injury. In this study, we aimed to better understand postural sway behavior and the mechanisms of balance control by examining balance in upright standing among PwS using methods from statistical mechanics i.e., the Stabilogram diffusion analysis (SDA). Center-of-pressure displacements while standing still were measured in 25 PwS and 11 healthy subjects. The traditional postural sway parameters were measured, and the SDA was used to characterize balance control in eyes-open and eyes-closed conditions. We found that PwS demonstrated significantly greater postural sway in the mediolateral and anterior-posterior directions and significantly higher SDA short-term diffusion coefficients and critical displacement in both eyes-open and eyes-closed conditions. There was also a significant group-by-condition interaction, whereas PwS demonstrated more sway in the eyes-closed condition. The SDA analysis revealed unstable behavior during short-term intervals, interpreted as larger distance of sway until closed-loop control took place. This significant group-by-condition interaction suggests that PwS have a significantly greater reliance on visual input compared with healthy subjects.

Pseudoperipheral palsy: a case of subcortical infarction imitating peripheral neuropathy

Background

Vascular damage in the central hand knob area can mimic peripheral motor nerve deficits.

Case presentation

We describe the case of a woman presenting with apparent peripheral neuropathy. Brain magnetic resonance imaging and computed tomography angiography revealed an infarct in the precentral hand knob area, with significant stenosis in the right proximal middle cerebral artery trunk. Subsequent 3-Tesla magnetic resonance imaging of the brain suggested cerebral angiitis. The patient experienced improved hand function following combined glucocorticoid and cyclophosphamide treatment.

Conclusion

Vascular damage in the hand knob area should be considered when evaluating peripheral motor nerve deficits in the presence of normal nerve conduction velocities. The diagnosis of cerebral angiitis remains a major challenge for clinicians.

Isolated hand paresis: a case series

BACKGROUND

Hand knob infarction is a well-known stroke entity. Based on very limited data, embolic stroke mechanism has been considered the most frequent cause; however, prognosis is considered good. We wanted to shed more light on this phenomenon by assessing a cohort of patients referred to a general hospital stroke unit.

METHODS

Every subject admitted to our stroke unit with an acute isolated hand paresis in the period from 2007 to 2012 was identified prospectively. Patients who had suffered from a stroke in the hand motor cortex or an adjacent area explaining the acute loss of hand function were included in the study. The Trial of Org 10172 in Acute Stroke Treatment criteria were used to classify subtypes of stroke according to etiology. The patients were followed up during autumn 2012.

RESULTS

Seventeen subjects were admitted, but in 2 of them symptoms were transitory and magnetic resonance imaging was negative. Two patients were excluded due to persisting sensory deficits. The remaining 13 (11 males and 2 females) patients with an average age of 62.9 (± 13.4) years were included, representing 1.5% of all ischemic strokes diagnosed at the stroke unit in the given period. All patients were right-handed, and the dominant hand was affected only in 4 (31%). The average Medical Research Council's scale score was 3.1 (± 1.4) on admission, and classified as bad. On follow-up, which occurred on average 29.8 (± 19.8) months after the stroke, the score was 4.6 (± 0.4) and was classified as fair to good. No patient experienced a new stroke. The outcome was good to excellent in 10 patients (77%). Two patients died (15%), 1 of probable cardiac arrest and 1 of unknown cause. One patient did not participate in the follow-up. The majority of patients had evidence of both small artery (77%) and large artery (85%) disease. On average, there were 1.6 (± 0.4) new ischemic lesions per patient. Six patients had a solitary lesion (46%). In 5 of them, small artery occlusion was considered the probable stroke mechanism. In 4 cases, the stroke was of undetermined etiology. Three patients had atrial fibrillation, and in 2 of them cardioembolism was the probable stroke mechanism. Two patients with definite large artery atherosclerosis underwent carotid endarterectomy, and 1 of them had comorbid atrial fibrillation.

CONCLUSION

Strokes causing isolated hand paresis seem to have a heterogeneous etiology. Prognosis regarding hand function is good, but long-term outcome depends on stroke etiology and secondary prophylaxis.

Diagnostic approach to peripheral neuropathy

Peripheral neuropathy refers to disorders of the peripheral nervous system. They have numerous causes and diverse presentations; hence, a systematic and logical approach is needed for cost-effective diagnosis, especially of treatable neuropathies. A detailed history of symptoms, family and occupational history should be obtained. General and systemic examinations provide valuable clues. Neurological examinations investigating sensory, motor and autonomic signs help to define the topography and nature of neuropathy. Large fiber neuropathy manifests with the loss of joint position and vibration sense and sensory ataxia, whereas small fiber neuropathy manifests with the impairment of pain, temperature and autonomic functions. Electrodiagnostic (EDx) tests include sensory, motor nerve conduction, F response, H reflex and needle electromyography (EMG). EDx helps in documenting the extent of sensory motor deficits, categorizing demyelinating (prolonged terminal latency, slowing of nerve conduction velocity, dispersion and conduction block) and axonal (marginal slowing of nerve conduction and small compound muscle or sensory action potential and dennervation on EMG). Uniform demyelinating features are suggestive of hereditary demyelination, whereas difference between nerves and segments of the same nerve favor acquired demyelination. Finally, neuropathy is classified into mononeuropathy commonly due to entrapment or trauma; mononeuropathy multiplex commonly due to leprosy and vasculitis; and polyneuropathy due to systemic, metabolic or toxic etiology. Laboratory investigations are carried out as indicated and specialized tests such as biochemical, immunological, genetic studies, cerebrospinal fluid (CSF) examination and nerve biopsy are carried out in selected patients. Approximately 20% patients with neuropathy remain undiagnosed but the prognosis is not bad in them.

Diagnosis and neuroimaging of acute stroke producing distal arm monoparesis

Strokes which result in the isolated, pure motor weakness of an upper extremity are unusual and under-recognized cerebrovascular syndromes. Few reports in the literature describe the syndrome adequately or provide substantive clinical or anatomical correlation. Moreover, it may be misdiagnosed as a disorder of the peripheral nervous system because of the lack of pyramidal tract signs or the involvement of speech, the face, or lower limbs. We describe 35 patients who presented with sudden isolated pure motor weakness of an arm or hand caused by stroke, and provide clinical anatomic correlation of the lesion, stroke etiology, and outcome. Between December 1997 and November 2002, we prospectively identified 35 cases of distal arm monoparesis (DAMP) from among 4818 acute stroke and stroke related admissions to the Lehigh Valley Hospital. We included all patients with isolated weakness of one arm or hand unassociated with objective sensory, coordination, or language deficit, and no significant involvement of speech, the ipsilateral face, or leg. We examined clinical features, neuroimaging, etiology of stroke, and the prognosis of patients with the syndrome over a mean follow-up of 1.7 years. DAMP is an unusual form of cortical infarct which occurs in the parietal lobe or central sulcus region, comprising less than 1% of stroke cases. The infarcts are not caused by classical deep white matter lacunar infarctions, and are clearly delineated as superficial small cortical infarcts by magnetic resonance imaging (MRI)/diffusion-weighted imaging (DWI). Although the prognosis for recovery is uniformly good, the recurrent stroke risk was 14% over 1.7 year mean follow-up.

Isolated hand weakness in cortical infarctions

Isolated hand weakness due to stroke is infrequently observed, and often misdiagnosed as peripheral lesions. This study investigated the clinical and radiologic profiles in such patients. Five men and one woman were studied. All patients underwent cranial magnetic resonance imaging (MRI) to confirm the diagnosis. Four patients had uniform weakness and the other two had either differential radial or ulnar weakness, respectively. MRI showed acute infarctions involving the hand knob area of the primary motor cortex (M1) in five patients and the postcentral gyrus sparing the precentral gyrus in one patient. Two patients with uniform digit weakness had additional involvement of the inferior parietal lobule. These findings suggest that isolated or predominant hand weakness in patients with cerebral infarctions is not necessarily caused by lesions in the M1 knob area, and that the control center of hand movement is not limited to the knob area alone.

Isolated Weakness of Middle, Ring, and Little Fingers due to a Small Cortical Infarction in the Medial Precentral Gyrus

SMALL CORTICAL STROKES CAN PRODUCE PREDOMINANT ISOLATED WEAKNESS IN A PARTICULAR GROUP OF FINGERS: radial or ulnar. The traditional views are of point-to-point representations of each finger to neurons located in the precentral gyrus of the motor cortex such that the neurons of the radial fingers are located laterally and those of the ulnar fingers are located medially. We present a case of isolated weakness of middle, ring, and little fingers due to a small cortical infarction in the medial precentral gyrus.