False Positive Hoover's Sign in Apraxia

Functional Neurological Disorder: Diagnostic Pitfalls and Differential Diagnostic Considerations

Functional neurologic disorder (FND) is a "rule-in" diagnosis, characterized by positive examination signs or semiological features. Similar to other clinical diagnoses, providers should ideally see robustly present features, including if possible the identification of multiple features consistent with FND for the diagnosis to be made with a high degree of certainty. Diagnostic pitfalls need to be guarded against and vary depending on FND symptom subtype and the specific patient presentation. This perspective article aims to review pitfalls based on an FND symptom subtype, as well as discuss differential diagnostic considerations with respect to both neurologic and psychiatric entities.

Lessons from a Neurologist After 25 Years of Functional Neurological Disorder Subspeciality Practice

The idea that a neurologist would do an 'FND clinic' or that functional neurological disorder (FND) could be a subspecialty of neurology would have been outlandish even 20 years ago but has become a reality in many places around the world. In this personal review, I reflect on 25 years of being a neurologist with an interest in FND, initially as a research fellow and later as a consultant/attending. I review lessons from diagnosis and management in the hope that they may assist other neurologists embarking on a similar career as well as other health professionals whose roles overlap.

Weak gluteus maximus and weak iliopsoas with normal gluteus maximus: Two complementary new signs to diagnose lower limb functional weakness

BACKGROUND AND PURPOSE

The diagnosis of functional neurological disorder should be actively made based on the neurological signs. We described two new complementary signs to diagnose functional weakness of the lower limb, "weak gluteus maximus (weak GM)" and "weak Iliopsoas with normal gluteus maximus (weak iliopsoas with normal GM)," and tested their validity.

METHODS

The tests comprised Medical Research Council (MRC) examinations of the iliopsoas and GM in the supine position. We retrospectively enrolled patients with functional weakness (FW) or structural weakness (SW) who presented with weakness of either iliopsoas or GM, or both. Weak GM means that the MRC score of GM is 4 or less. Its complementary sign, weak ilopsoas with normal GM, means that the MRC score of ilopsoas is 4 or less, whereas that of GM is 5.

RESULTS

Thirty-one patients with FW and 72 patients with SW were enrolled. The weak GM sign was positive in all 31 patients with FW and in 11 patients with SW, that is, 100% sensitivity and 85% specificity. Therefore, the complementary sign, weak iliopsoas with normal GM, was 100% specific for SW.

DISCUSSION

Although 100% should be discounted considering limitations of this study, these signs will likely be helpful in differentiating between FW and SW in the general neurology setting. Downward pressing of the lower limb to the bed in the supine position is interpreted by the patient as an active movement exerted with an effort and might be preferentially impaired in FW.

Functional neurological symptoms as initial presentation of Creutzfeldt-Jakob disease: case series

BACKGROUND

Functional Neurological Disorders (FND) are common in clinical practice. It is recognized that FND may present at onset or during the course of other neurological diseases (functional comorbidity).

CASES

We report a clinical series of three patients who initially presented positive signs of a functional movement disorder (FMD) and were later diagnosed with a Creutzfeldt-Jakob disease (CJD). All patients presented with unilateral functional tremor, two patients also had functional limb weakness. All patients progressed to an asymmetric corticobasal syndrome, fulfilling clinical criteria of CJD. They had a rapid progression and died within 2-3 months.

CONCLUSIONS

FND may be the initial clinical presentation of neurodegenerative diseases reflecting a dysfunction across brain circuits that are involved in the pathophysiology of FND. A positive diagnosis of FND is essential as it is an adequate examination and a close follow-up of these patients in neurology clinics.